Hello BIMfans,
As I wrote in the Prologue, the idea for There’s No BIM Like Home was born when my wife and I were buying our first house. During this purchase, I quickly realized that we were given an awful lot of paperwork to manage but no way to manage it.

The Master File
I’d have been in real trouble if this went missing, but no longer!

As a Chartered Architectural Technologist who specializes in information management using Building Information Modelling (BIM), I set out to produce and manage an information model of Tŷ Crempog.  The aim was to collect enough information to satisfy the Model Purposes I had identified:

  • Register
  • Operations
  • Maintenance and Repair
  • Replacements

To ensure these purposes where met, I undertook both verification and validation activities of the information I produced.

Verification:  Verification came from two sources. Principally from you, the readers, who would spot errors and inconsistencies (thank you, and keep those corrections coming). In addition, a key verification milestone was when John Ford took my COBie and verified it using the COBie QC Reporter.

Validation:  Validation on other hand came from my physical testing of this information, which I do on a daily basis, showing that Size Doesn’t Matter when it comes to BIM. I also validated information when it could be used to answer a Plain Language Question.

During this journey I’ve answered these all of these questions, having produced over 60 blog posts, which have had over 50000 unique views in 130 different countries. With these views came recognition in the form of positive reviews from you, the readers, as well as Testimonials from key BIM professionals such as Nick Nisbet and David Philp.

Wow, thank you guys so much!! I’m sure VPNs had no influence on this whatsoever…

However, the work of There’s No BIM Like Home is far from over.

The most popular blog posts I’ve written is BIM Explainer, my plain language post; telling me that there are still issues around BIM education and communication. In addition, my other popular posts have been related to the practical application of standards such as:

Showing that there is a real appetite for practical demonstrations that show how these standards, methods, and procedures can be applied. As such, I plan to maintain the posts on this blog to ensure they align with industry developments and reflect good practice; for example, when ISO 19650-1 and ISO 19650-2 are published, when other standards are updated, or when new technologies are available.

So, please continue to visit this blog to keep up-to-date with good practice standards, methods, and procedures related to the use of information management using Building Information Modelling (BIM). Remember, while there may be some great mega-projects out there, There’s No BIM Like Home.


Note:  If you have any comments regarding my epilogue or want to let me know your thoughts about this blog, then please let me know either on Twitter or by commenting below.

PLQ 3.4 – Inspired Improvements

Hello BIMfans,
By writing PLQ 3.4 – EPConclusion, I was able to complete the calculations for my Energy Performance Certificate (EPC) Rating.  Having made this information readily available, I issued a challenge to see what thermal improvements you would suggest.  I’m glad to say I received a plethora of suggestions (thank you everyone!) and have included the most detailed suggestions below.

NOTE:  To ensure that these suggestions were as realistic as possible, I have aimed to achieve the minimum requirements set out in the Welsh Approved Documents.  While I could have considered a higher benchmark such as enerPHit, I wanted to ensure that I could afford and justify the improvements described below, so they might actually be implemented.

Floors and Roofs (+5 SAP points):

This suggestion came from Craig Hardingham of MLM, who felt I would benefit from insulating between by floors and roof joists using a product like Rockwool.

Regulations:  According to the Welsh Approved Document L1b, I need to achieve a maximum u-value of 0.25W/m²K if I upgraded the thermal performance of my floor and 0.16W/m²K if I upgraded the performance of my roof.  While there are plenty of high-performance insulation materials, Rockwool is an excellent suggestion for two reasons:

  1. It is a mineral fibre, so if I use it between my joists it would keep the assembly breathable and the Rockwool can accommodate any warping or shape variation;
  2. Rockwool are good Welsh firm!

For my floor, I have chosen ROCKWOOL FLEXI.  Using my graphical model, I am able to calculate the perimeter and area of my floor to determine a P/A Ratio of 1.2, which means I need 140mm of ROCKWOOL FLEXI to achieve the desired U-value.

For my roof, I have chosen ROCKWOOL Roll, Twin Roll and Rollbatt.  If I cross-layer the insulation I would need a total of 270mm to achieve the desired U-value.

Modelling:  To undertake both of these calculation, I don’t need to edit my geometry, but I do need to add new properties to capture the thickness of my insulation. I couldn’t find an ideal property within the IFC Data Schema, so I have made my own:


NOTE:  I used -thickness because of xBIM doesn’t export properties with -Width, -Height, -Length suffixes to prevent duplication of information between different worksheets.

By placing this property onto my levels, I was able to get it into COBie to form part of my calculations without altering the exclusion list.


SAP:  For SAP Calculations, floor U-values (28a) are calculated based on a bespoke formula.  With an assumed thermal conductivity of 0.035 W/mK, the Rf value of my floor would increase to 4 instead of my default 0.2.  In addition, I would also seal my floor reducing the floor infiltration rate (12).  For my roof U-value (30) a new figure of 0.16 W/m²K is taken from table S9.

Based on the above, upgrading the insulation in my ground floor suspended timber floor and roof would improve my SAP score by an impressive five points.

Walls (+6 SAP points):

This suggestion came from John Hefford of Thermal Economics, who felt I would benefit from thermal dry-lining using Alrefelx Platinum while Emma Hooper of Bond Bryan Digital felt I would benefit from using Properla’s Masonry Creme.

Regulations:  According to the Welsh Approved Document L1b, I need to achieve a maximum u-value of 0.30W/m²K if I upgraded the thermal performance of my external walls.  To be honest, I hadn’t considered dry-lining however, due to my solid walls and flush fascia, cavity-fill and external wall insulation (EWI) systems are not feasible. Luckily, as John suggested a high-performance dry-lining system, I would only need 75mm to achieve the desired U-value.  Also, thanks to Emma’s suggestion by combining Alrefelx Platinum with Properla Masonry Creme, I would (in theory) only need 65mm.  This is because, while they have no BBA certificate demonstrating this, Properla has shown to improve the thermal conductivity of masonry to 0.355K (w/mK).

Modelling:  Post-installation, someone like  Thermal Economics could do a U-value test to provide to the SAP Assessor.  Otherwise the SAP Assessor would assume a much worse U-value of 0.6W/m²K.  This value would be place on my wall elements, but they would not appear in COBie, as such I would instead reference the test results and manually input this information.

NOTE:  I could cheat and place a property like ‘WallThermalConductivity’ onto the house, but this defeats the object of having a schema.  I’d like to remind you all that documents are not taboo in BIM!

SAP:  For SAP Calculations, the Wall U-value (29a) would use a new figure of 0.3W/m²K, and the walls heat capacity (29a) would also need to be updated to 9 kJ/m²K.  In addition I would need to remove 0.517m² from the ground floor area (1b) and 0.788m² from the first floor area (1c).

Being a mid-terrace home makes internal insulation much more efficient

Based on the above, treating and dry-lining my external walls would improve my SAP score by six points.

Windows (+2.5 SAP Points):

This suggestion came from Natasha Jayne Vermeulen of Whittam Cox Architects, who felt I would benefit from upgrading my windows using FORMAPLUS from Rationel.

Look at it, it’s like a work of art!

Regulations:  According to the Welsh Approved Document L1b, I need to achieve a u-value no worse than 0.16W/m²K when upgrading my existing windows.  Luckily, FORMAPLUS provides a U-value of 1.29W/m²K; making it an ideal solution.  Also, I love the look of wooden windows with an aluminium facade!

Modelling:  I discovered that Rationel have their windows on BIM Object.  However, these objects are quite frankly useless.  For example, the object I chose included a property called ‘U-value’ (should be ThermalTransmittance) which is formatted as text, instead of a number.  Meaning that it’s value ‘0,8’ (note the comma) doesn’t respond to project units, cannot be used for analytics and breaks my SAP Calculations!  So, I just used my own objects instead and added the properties I’ve previously discussed.

With objects like these, who needs enemies!

SAP: For SAP Calculations, now that I have updated the properties in my model, I am able to update my window U-values (27) to reduce heat loss and their G-values and Frame factors (74-82) to adjust solar gain.

Based on the above, replacing my windows with Rationel  FORMAPLUS would improve my SAP score by two and a half points.

Boiler (+4 SAP Points):

This suggestion came from Darryn Marrs of Jonathan-Rhind Architects, who felt I would benefit from upgrading my boiler to biomass or a high-efficiency gas boiler.

Darryn was kind enough to make a suggestion but unfortunately didn’t suggest a product.  So, I decided to have a look at the Building Energy Performance Assessment support website, which includes the relevant product data to inform my SAP Calculations.  Using this site I was able to select the Worcester, Greenstar CDiNote:  I have a Worcester Greenstar, so (in theory) choosing another Greenstar should ease this process.


Regulations:  As I am not intending to move my flue or change the position of my boiler, I do not believe there are any regulatory issues I need to consider. (Phew!)

Modelling:  I couldn’t find a BIM object for this boiler, so I used my current boiler family and increased the boilers size to suit and updated OperationalEfficiency to 90.

To be honest, I still think my boiler’s geometry is too complex

SAP:  Now that I’ve updated my model, Boiler efficiency (206) and (216) are significantly improved  to 90 and my boiler’s electric load (230c) has been reduced down to 30kW/year.

Based on the above, replacing my boiler with a Worcester Greenstar CDi would improve my SAP score by four points.

Sum Total:

Amazingly, if I did all of the improvement works identified above, my SAP Calculations would go from 66 to 81.5.  This is a 15.5 improvement, bringing  Tŷ Crempog from an EPC of D to B!!  Note:  Those of you who kept count would have noticed that my improvements add up to 17.5, not 15.5.  This is because improvement to my external floor, wall and roof insulation mitigates the gains from a more efficient boiler; improvements need to be considered holistically.

Jump Crempog, Jump to a more sustainable home!

And there we have it.  With these inspired improvements based on my SAP Calculations, I now know what work can be undertaken and have enough information to collect quotations.  This means that my final Plain Language Question, PLQ 3.4 is complete!

Operation and Maintenance

  • 3.1 What are the sizes and condition of the windows & doors?
  • 3.2 What assets are in a poor condition?
  • 3.3 What costs can be attributed to my assets?
  • 3.4 What are the most cost effective thermal improvements that could be undertaken?

Now that all of my Plain Language Questions have been completed, I should probably look to undertake some of these improvements…

Note:  If you have any comments regarding these inspired improvements, then please let me know either on Twitter, or by commenting below.

Is It Smart? – Conexis L1

Hello BIMfans,
Welcome to ‘Is It Smart?’, the blog series where I have a look at the smart technology installed within Tŷ Crempog to explore the power of BIM Level 2, PropTech, and the Internet of Things (IOT).  This week, I take a look at the Conexis L1.

Those of you who follow me on Twitter will know that I have recently had Yale‘s Conexis L1, a keyless smart lock, installed.  I have always liked the idea of having a keyless home, so when I arranged for BWM Ltd to install my new back door, I thought it was the perfect opportunity to have them also install the Conexis L1.

What is it?

The Yale Conexis L1 is a keyless smart lock, suitable for multipoint locks, which meets PAS 24 and can be managed entirely from the Yale app.

I could say more, but I think this advert sums up what the Conexis L1 is nicely.


How does it work?

A key by any other name…

Instead of keys, the Conexis L1 uses the Yale app to register fobs, key cards, tags or smartphones to gain access through a combination of RFID and Bluetooth.  Because these access methods are managed through the Yale app it means that access can be revoked if any of these devices are lost.  Otherwise, the Conexis L1 works just like a hotel door lock.

How Did I Model it?

I haven’t (well at least not properly).

Because the Conexis L1 is a part of my front door, the modelling options are quite limited.  I could have used something like IfcSwitchingDevice, IfcDiscreteAccessory or (when in doubt) IfcProxyElement.  However, because of the way Revit works, ironmongery, like handles and locks, are typically nested onto their host objects.  This means that if I put any information onto this object, none of it would be exported into IFC or COBie.  However, I have already modelled a door handle, so I have modified this object to reflect my new smart lock t improve the accuracy of my doors geometry.

This locks like an information rick object; but it isn’t…

Is It Smart?

The Conexis L1 ticks some of the right boxes to be considered smart.

  • Data In:  The Conexis L1 maintains a list of devices that can be used for access as well as a history of devices that have locked/unlocked the door and when.  All of this information is available through the Yale app (which is probably the worst app I have ever used!).  Otherwise, the lock itself collects no other information.
  • Data Out:  Unfortunately, this is where the Conexis L1 really falls short.  As far as I can tell, there is no method of exporting any information.
  • Connectivity:  The Conexis L1 cannot connect to other devices as standard, but using a Z-wave Module, its connectivity can be expanded to connect to the Yale Smart Living Home App and third-party devices like the Samsung Smart Things Hub.  However, this connectivity comes at a cost as there are ways that the Z-wave module can be hacked (Thank you Rene for sending me this).  Luckily for me, I don’t have a Z-wave Module, so my lock is safe and sound!

The Potential

One thing I wish the Conexis L1 did was to confirm whether the door was currently locked or not.  However, without internet access, or a Z-wave Module, this wouldn’t be possible.  Otherwise, there isn’t much more I can expect a smart lock to do!

One thing I will say is that the smartphone unlock is terrible!  Using Bluetooth instead of RFID is takes ages to unlock and the “Twist and Go” gesture is quite unreliable.  It would work so much better if it used RFID.  While there might be security issues, RFID is used for contactless payment, so I’m sure there are solutions.  For now, I’ve now placed a key card in my phone case so I can bump my phone against the lock and instantly open my door as it if was RFID controlled.  A man can dream…

The Verdict

Is It Smart? The answer is sort-of, with a mediocre IQ of 100!


Out of the box, the Yale Conexis L1 isn’t particularly smart.  However, by using a Z-wave Module the lock becomes much much smarter; capable being controlled by voice and through IFTTT.  Once connected, the Conexis L1 provides all of the functionality you would expect from a smart lock.  However, gaining a direct connection to Google Home or Google Assistant (and a decent amount of development work on the app!) would help make the Conexis L1that much smarter.

And there you have it.  This week my Conexis L1 proved to sort-of smart.  Tune in next time where we take a look at another piece of smart technology and ask one simple question; Is It Smart?

PLQ 3.4 – EPConclusion

Hello BIMfans,
After previously considering my Overall Dimensions, Heating Requirements and Internal Gains, I am now able to complete my Standard Assessment Procedure (SAP) calculations by looking at my final three categories:  9a_Energy Requirements, 10_Fuel Costs, and 11_SAP Rating.

Go on Crempog, climb those ratings!

Energy Requirements

  1. Space Heating (211).  To calculate the amount of energy needed to heat Tŷ Crempog, SAP requires the previously calculated monthly space heating requirements (98) as well as my boiler’s efficiency (206).  Using the SAP Product Database, I was able to find an efficiency rate of 76.1%.  As expected, my boiler’s efficiency has a significant effect on the energy needed for space heating (211).

    The SAP product database can be accessed from here.
  2. Total Electricity (services) (231).   In a similar vein, as my boiler was installed before 2013 I’ve had to use 120 kWh/year instead of an assumed 30 kWh/year.  This means that, in addition to any efficiency gains, I could quarter the energy use associated with my boiler by having a new one installed.
  3. Total delivered energy for all uses (238).  Each of the calculated energy uses were collated to calculate my total delivered energy.  Interestingly, SAP includes an opportunity to subtract renewable energy sources; making the addition of solar panel an option to consider.  However, as my roof faces east and west, this option might not be as attractive as it seems. 

My SAP calculations for energy requirements can be seen below:

Fuel Costs

  1. Total Energy Cost (255).  As I am not able to choose my fuel, there isn’t much I can do to influence this cost aside from reducing my energy requirements.

My SAP calculations for my fuel costs can be seen below:


SAP Rating

  1. SAP Rating (358).  After all of these calculations, I’ve come to a final value. Using the total energy cost (255) of Tŷ Crempog and total floor area (4), I am able to calculate the energy cost factor (357); allowing me to calculate my SAP rating (358).Months of calculations and tests have allowed me to arrive at a single number, 66.50.  My ‘official’ SAP rating you ask? 65 (Pretty damn close if you ask me!).

My SAP calculations for SAP Rating can be seen below:

To double-check these figures (and increase my level of confidence), I contacted BRE’s Energy Team, who were kind enough to review my calculations.  After a few exchanges, I believe we have managed to spot and correct most, if not all, of the errors to arrive at a pretty realistic SAP score.  This means that I am able to test scenarios and see the impact any improvements have on Tŷ Crempog.

Now that my calculations are complete, I am happy to share them:

Having these calculations in Google Sheets is great because I am able to share and test these results.

It is so easy, I am issuing a challenge:

What are the most cost-effective thermal improvements that could be undertaken?

Using the structured information provided in my Calculation Sheet and SAP Documentation, what improvements can you test and suggest back?  The best suggestions will feature in next month’s blog post!!!  For example:

  • Backdoor:  A new backdoor would improve (26a) from 3.00 to 1.4; increasing my SAP rating by (an unimpressive) 0.3.
  • Boiler:  A new boiler would improve (206) and (230c); increasing my SAP rating by up to six whole 6 points!

So, let your creativity flow, and see what solutions you can think of:

Answers in the comments section below or via social media, please!

And there we have it.  Having now completed my SAP Calculations using Tŷ Crempog‘s information model, I should now (with your help) be able to determine the most cost-effective thermal improvements that could be undertaken.  In doing so, PLQ 3.4 will be complete!

Operation and Maintenance

  • 3.1 What are the sizes and condition of the windows & doors?
  • 3.2 What assets are in a poor condition?
  • 3.3 What costs can be attributed to my assets?
  • 3.4 What are the most cost effective thermal improvements that could be undertaken?

Now that my SAP rating has been calculated, Let’s see what potential improvement works you lot have suggested…

Note:  If you have any comments regarding my use of SAP, then please let me know either on Twitter, or by commenting below.

PLQ 3.4 – No Pain No Gain

Hello BIMfans,
As you are aware from my Previous Posts, I am currently working my way through BRE‘s Standard Assessment Procedure (SAP) by importing structured information from Tŷ Crempog‘s information model.  As I covered ‘how’ during SAP Likes it Hot, I’ve opted to go for quantity and have completed the majority of my SAP calculations.  While there were some suspect values (at one point I had a negative utilization rate), I’m in no way confident that these issues have been resolved.

Me for most of these calculations…

For this post, I’ve managed to complete: 4 Water Heating, 5 Internal Gains, 6 Solar Gains, 7 Internal Temperature and 8 Space Heating.

  1. Total Hot Water Usage (44).  To calculate the amount of hot water used, SAP uses an assumed occupancy (42) based on the dwelling’s total floor area (4) and default cold water values.  As such, without changing Tŷ Crempog‘s floor area, there isn’t much I can do here!  Also, the energy content of my hot water (45) is shown on my EPC.  As I have calculated a value of 1522 compared to my ‘official’ 1543, I can be confident in my figures so far.  Note: 1543 is based on a Total Floor Area (4) of 81m² as opposed to my 78.3m².


  2. Energy Loss (55) As Tŷ Crempog has no water storage, this is an easy 0.  Can’t do better than nothing!
  3. Total Water Heating Output (64).  As water heating output is solely based on hot water usage, I cannot impact positively on this value through refurbishment work.

My SAP calculations for water heating can be seen below:

5 Internal Gains

  1. Total Internal Gains (73).  As you can imagine, there are a lot of internal heat sources within a dwelling.  However, metabolic, cooking gains and losses are calculated based on assumed occupancy (42) and appliance gains are based on total floor area (4); meaning no scope for improvements.  The exception is lighting gains.  Lighting gains take into account whether low energy bulbs are used (C1), window light transmittance (gl) and frame factor (FF).  I already have low energy bulbs throughout Tŷ Crempog, meaning that replacing windows is the only way to impact positively on these gains.

My SAP calculations for internal gains can be seen below:

6 Solar Gains

  1. Solar Gains (83).  Similar to my internal gains (73), solar gains depend on the window frame factor (FF), light transmittance and G-value (g1).  In preparation, I populated my architectural model with some additional properties.  Luckily for me, the properties I need are already within the IFC Schema:

    VisibleLightTransmittance; and

    I needed to produce new properties for the others.  So using the requirements for property naming within BS 8541-4 I settled on:

    SolarEnergyTransmittance; and

    Disappointingly,  as I cannot determine the exact products used, SAP states I have to resort to the default values.  Note:  This really annoyed me.  My installer appears to no longer be in business.  This shouldn’t have been an issue as I have a FENSA certificate with a BFRC reference.  However, it turns out the information about my windows hasn’t been retained by FENSA or BFCR.  Meaning my windows properties have been lost to the ages…  Once again, replacing windows is the only way to impact positively on these gains.

My SAP calculations for solar gains can be seen below:

7 Internal Temperature

  1. Mean internal temperature (92)Building on my previous calculations, mean internal temperature is calculated using Tŷ Crempog‘s total internal gains (84), thermal mass capacity (35) and heat loss parameter (39).  Meaning that the mean internal temperature would benefit from external wall, door and window thermal improvements.

My SAP calculations for internal temperature can be seen below:

8 Space Heating

  1. Space Heating (99).  All of the previous calculations help determine Tŷ Crempog‘s space heating requirements.  Using the default external temperature values (96) along with heat loss parameter (39), solar gains (83) and mean internal temperature (92), space heating (98) could (finally!) be calculated.  As another value that appears on my EPC, I have calculated 10531 against the official 10662; once again suggesting that my figures are correct.  By dividing this value by my dwelling volume (5), I get Space Heating (99).

My SAP calculations for space heating can be seen below:

And there we have it.  As I progress deeper into SAP using Tŷ Crempog‘s information model, I am beginning to discover what properties I should consider when planning refurbishment works.  Fantastic, PLQ 3.4 is almost complete!

Operation and Maintenance

  • 3.1 What are the sizes and condition of the windows & doors?
  • 3.2 What assets are in a poor condition?
  • 3.3 What costs can be attributed to my assets?
  • 3.4 What are the most cost effective thermal improvements that could be undertaken?

Now that space heating has been calculated, I now need to look at Ty Crempog‘s energy requirements and fuel costs to complete my SAP calculation…

Note:  If you have any comments regarding my use of SAP, then please let me know either on Twitter, or by commenting below.

PLQ 3.4 – SAP Likes It Hot

Hello BIMfans,
In my last post, I introduced BRE‘s Standard Assessment Procedure (SAP) and began my SAP Calculations by importing Tŷ Crempog‘s areas and dimensions from my Architectural COBie.  For this post, I’ve built on my initial calculations and have had a look at 2 Ventilation Rate and 3 Heat Loss.

As a Chartered Architectural Technologist, I’ve always tried to understand the science behind the built environment.  When working in practice I did my own thermal calculations, and have previously designed to meet Passivhaus.  This exercise has enabled me to rekindle that interest by combining thermal calculations, structured information, and information exchanges.

The built environment is often misunderstood even by boy wonders.

2 Ventilation Rates

  1. Infiltration Rate due to chimneys, flues, fans, PSVs (8).  As I have two intermittent fans within Tŷ Crempog, I needed to capture their Information. Luckily for me, as I used the naming convention within ISO 4157-1 as discussed in Naming Omnibus, I could extract the number of fans from my Electrical COBie using this Excel formula:

    =COUNTIF(importrange(, “Component!A:A”), “*Fan*”)

    Note:  Fan01 is my extraction hood with no external penetration.

    This means that I cannot improve this value through refurbishment work unless I invest in Bathroom Dehumidifiers.

  2. Infiltration rate (16).  The best way to calculate infiltration is through a pressurization test.  However,  SAP provides an alternative calculation method (saving me £300-ish).  This calculation is based on several default values as well the number of storeys (9), structural infiltration (11), floor infiltration (12), draft proofing (13) and window infiltration (15).  Of these, I need a new property to capture Tŷ Crempog‘s draft proofing.  After being unable to find a suitable property in the IFC schema, I created my own.
    After giving it some thought, I’ve settled on ‘HasDraftProofing’.

    ‘HasDraftProofing’ was chosen after reading BS 8541-4, which required I use CamelCase and indicating the data type expected.  Draft [sic] is used in other parts of the IFC schema so I kept it for consistency.  I used ‘Has’ over ‘Is’ as I am checking for draft proofing accessories, not checking the performance of the doors and windows (they could have draft proofing, but not be draft proof!).  This new property was added to information model and exchanged into my Architectural COBie.  Because all of my windows are doors are already draft proofed, sealing my floor or undertaking an air pressure test are the only ways to impact on infiltration rate.

  3. Effective air change rate (25).   Using default wind speeds along with infiltration rate (16), effective air change can be calculated.  If I want to take performance improvements seriously, it appears that a pressure test is a must.

My SAP calculations for ventilation rate can be seen below:

3 Heat Loss

  1. Area of external elements (12).  RdSAP included default areas for my door and windows.  To be honest, these assumed values put me at a disadvantage as windows are calculated as a factor of floor area.  Using my Door and Window Schedule, I know that I have ~12m² of windows.  However, RdSAP‘s assumptions provide:

     0.1220*TotalFloorArea + 6.875 = 16m²

    While the impact is small, every little helps.  Perhaps I need to check what values I can override if they are available.

  2. Average Heat loss Parameter (40) To calculate average heat loss, I discovered that U-values are a critical factor (D’uh).  As I have solid brick walls with no insulation, I’ve had to use the (pitiful) U-value of 1.55W/m²K.  Similarly, as I don’t know what’s under my floor, or what specific windows are installed I have to use the default values provided.  However, I do know what my front door is.  As such, I was able to use 1.4W/m²K instead of the default of 3W/m²K.  It seems that simply having this information available is half the battle.  From a quick test, insulating my external walls and floors would half my heat loss.  Clearly, upgrading external elements and solutions such as External Insulated Facade Systems (EIFS) will be worth considering.

My SAP calculations for heat loss can be seen below:

And there we have it.  As I progress deeper into SAP using Tŷ Crempog‘s information model, I am beginning to discover what properties I should consider when planning refurbishment works.  Fantastic, PLQ 3.4 is progressing well!

Operation and Maintenance

  • 3.1 What are the sizes and condition of the windows & doors?
  • 3.2 What assets are in a poor condition?
  • 3.3 What costs can be attributed to my assets?
  • 3.4 What are the most cost effective thermal improvements that could be undertaken?

Now that my ventilation and heat loss calculations have been completed, I now need to look at Ty Crempog‘s hot water supply, internal gains, and solar gains…

Note:  If you have any comments regarding my use of SAP, then please let me know either on Twitter, or by commenting below.

PLQ 3.4 – Frank SAPpa

Hello BIMfans,
Now that I’ve produced Tŷ Crempog‘s information model, it’s time (finally) to put it to practical use in answering my next and final Plain Langauge Question:

What are the most cost-effective thermal improvements that could be undertaken?

By answering this Plain Langauge Question, I am beginning to realize the true potential of Tŷ Crempog‘s information model by answering real questions that will impact on how I undertake any retrofit works.  To answer this question, I have turned to Standard Assessment Procedure (SAP).


SAP is Building Research Establishment (BRE)‘s procedure to calculate the energy rating of dwellings.  SAP is referenced in Approved Document L of the Welsh and English building regulations, adopted by the UK Government and is used to assess dwellings to produce their Energy Performance Certificate (EPC).  New dwellings use SAP in its entirety while, as of November 2017, existing dwellings like Tŷ Crempog (or Joe’s Garage) use the Reduced Data Standard Assessment Procedure (RdSAP) to support completing the SAP calculations.

The advantage of RdSAP is that it provides several permitted assumptions that can be used within the SAP calculations.  I plan on using Tŷ Crempog‘s information model to complete the hundreds of values required.  Now there are too many to do at once, so instead of having a Freak out! I am addressing each section at a time; using RdSAP to fill in the gaps.

Once my SAP calculations are complete, I will be able to manipulate the information to see what improvements will provide the greatest impact.  For example, would it be more cost effective to improve Tŷ Crempog‘s thermal performance, reduce the infiltration rate or improve the efficiency of my heating system?  Once complete, I will be able to test these scenario’s and inform future home improvements.

BIM, placing asset information into the palm of my hand


1 Overall Dimension

  1. Total Floor Area (4).  To determine the total floor area,  SAP asks for the areas of each floor, which is calculated using the internal dimensions and storey heights.  While my Architectural COBie has internal space areas, I didn’t have a value for the Gross Internal Area (GIA) or the average height of each storey (many of you will know my battle with Storey, Floor, Level).

    To resolve this, I did area calculations within my model, and placed those values onto two new properties:


    Once I had exported these properties to COBie, I could populate my calculations automatically (WhooHoo!).   This is because I have used Google Sheets which allows me to reference other external Google Sheets using formulas like:

    =SUM(importrange(“URL”, “Sheet!Range”))

    Which also means that any updated I do to my information model will be reflected in my SAP CalculationsNote: my EPC was calculated within a total floor area of 81m², this difference will likely affect other values as I proceed with my calculations.

  2. Dwelling Volume (5).  Once I had imported GrossPlannedArea and MeanStorey, calculating Tŷ Crempog‘s volume was straightforward.

My SAP calculations for overall dimensions can be seen below:

And there we have it.  While I have only just started, it seems possible to automate the population of SAP using Tŷ Crempog‘s information model, using COBie.  This fills me with a lot of confidence that I can use my information model to complete the other SAP sections.  Fantastic, PLQ 3.4 is underway!

Operation and Maintenance

  • 3.1 What are the sizes and condition of the windows & doors?
  • 3.2 What assets are in a poor condition?
  • 3.3 What costs can be attributed to my assets?
  • 3.4 What are the most cost effective thermal improvements that could be undertaken?

Now that my overall dimensions have been calculated, it is time to look at Ty Crempog‘s ventilation rate and heat loss…

Note:  If you have any comments regarding my use of SAP, then please let me know either on Twitter, or by commenting below.

Structured Safety

Hello BIMfans,
With the recent release of PAS 1192-6, the newest core BIM Level 2 publication, there is now a specified process on how to share structured health and safety information.  So, let’s try it out and see if we can deliver this information!

EIR Invocation:

First things first (ironically), If an Employer wants the project’s health and safety information structured as specified with PAS 1192-6, then they will need to say so in their Employer’s Information Requirements.  So, as PAS 1192-6 is now specified in my EIR, I guess I’ll have to follow it.

(open) BIM Usage:

According to PAS 1192-6, 4.3 because I am modelling Tŷ Crempog using BIM processes, clauses 9 (COBie) and 10 (IFC2X3) apply.

From reading this PAS, it is clear that health and safety knows no vendor.  To comply, information shall be shared in open standard structured formats.  Meaning that thanks to PAS 1192-6, IFC2X3 is now a normative BIM Level 2 requirement (Woohoo!).  Thankfully this doesn’t impact on the most important BIM file format…

Loving you is easy ’cause you’re…controlled by ISO/IEC 29500

Clause 10 (IFC):

As only maintainable objects should be captured in COBie, there needs to be a method of capturing risks about other objects; this is where PAS 1192-6, 10 comes in.  It specifies that all health and safety information being shared shall be captured using HS_Risk_UK, a new property set specified within PAS 1192-6, Appendix ANote:  During the final edit, the first column of this table was incorrectly given spaces.  To comply with BS 8541-4, the properties should be written in CamelCase.

Once corrected, I added this property set into my PSet Definition Text File and created Revit shared parameters to match.  Thanks to the changes to my IFC Export Process, my Electrical IFC File now captures this information and places it into the correct property set.



The ease of adding this information was a shocking revelation


Risks can also be non-object related. When this is the case, PAS 1192-6 says that annotation entities (a.k.a floating risk signs), should be used.  To know what these entities should look like, PAS 1192-6, 4.3.3 states that BS ISO 3864-3 should be used.  Note:  This isn’t correct, as BS ISO 3864-3 tells you to use the symbols within BS EN ISO 7010.  Unfortunately, beyond this, PAS 1192-6 provides no further guidance.

This presents a problem.  With only the example being a screenshot in the appendix; I’ve had to go it alone and have produced what I feel is a pragmatic solution.

They say every sign has a story; this looks more like a hare-brained scheme

Shown above is my Master Warning Annotation Entity which has been produced to include all* warnings as separate types (*Only electrical and fall warnings have been added so far).  I have made this entity 700x700mm, 10 times the sign size outlined in BS EN ISO 7010), with a 7mm simplified symbol that displays on drawing plans.  Note:  The symbol is simplified because Revit can’t do lines small than 0.8mm, stupid Revit.

Also, due to the lack details on how to produce annotation entities, I also used the following additional sources to help:

  • BS 1192.  My annotation entity is named ‘Z-PM_80_60_70-M_WarningSymbol‘ to comply with BS 1192Note:  You might have thought that I’d use BS 8541-1. However, this isn’t an object, it’s a symbol. BS 1192 covers the naming of containers with files (i.e. symbols).
  • BS EN ISO 7010.  I extracted the symbols I needed and recreated them using several solid extrusions.  For the sign colour, I used online tools to get the RGB code (243 200 30) and set it to 20% transparency so that the object wouldn’t be opaque.
  • Uniclass 2015Finally, I wanted to give this object a Uniclass 2015 classification.  After some thought I settled on ‘PM_80_60_70: Residual risk information’ as the while the nature of the risk might change, at least all of these objects would be grouped under the same classification.

I might be a little bias, but I think my annotation entity looks quite fancy in my Electrical Native Model FileNote:  The rabbit silhouette is technically not BS EN ISO 7010 compliant.

Now for the real question, will Crempog check the information model before he tries to chew my cables?


COBie, unfortunately, took a lot more effort.

While I had managed to export this information into IFC, after testing xBIMXplorer, the COBie Extension for Revit and BIMserver (Thank you Emma), I couldn’t get the issue sheet to populate.  This was because PAS 1192-6 introduced HS_Risk_UK and with it a new method of structuring risks.  Existing COBie export tools haven’t yet reacted to this new process.  Currently, COBie looks for approvals to populate its issue sheet, but it is now having to look for objects.  Note:  While PAS 1192-6 appears to go against IFC2X3, the authors have confirmed that HS_Risk_UK is a draft proposal for updating Pset_Risk so feedback on this process will be used to update the IFC Schema.

Luckily I had a plan.  As I know the members of xBIM Development Team, I could ask them to patch the exporter to comply with PAS 1192-6.  Looking at xBIM’s GitHub, I identified the problem and proposed a rough solution for them to test and implement.  After a few emails, some black magic and only a couple of hours, we had managed to successfully export COBie with the issue sheet being populated as intended.  Note:  To get the validation to work, I’ve had to expand my picklist further to capture the new enumerations.

Note:  This patch is now live, anyone using xBIMXplorer can now benefit from the fantastic work that the xBIM Development Team have done.  

Those of you who have been following this blog will know that xBIMXplorer is my go-to IFC/COBie tool.  While it isn’t perfect, it’s free, open-source and as I’ve shown in this post, able to quickly respond to user needs.  I highly recommend you try it for yourselves.

If however, you want to comply with PAS 1192-6 but don’t want to build xBIMXplorer, there is another way.  After I asked for help on Twitter,  Nick Nisbet of AEC3 volunteered his help and also managed to use the same IFC files to automate the export of PAS 1192-6 compliant information using AEC3 BimServices 2018.  If you need a bit of COBie support, I’m certain that Nick can help.

And there we have it.  Less than a week after PAS 1192-6 was released, the processes have been tested and successfully demonstrated.  I managed to test HS_Risk_UK myself and thanks to Nick Nisbet and the xBIM Development Team, we have shown that automated COBie population of the issue sheet is possible using more than one method; fantastic!

Note:  If you have any comments regarding my structured health and safety information or PAS 1192-6, then please let me know either on Twitter, or by commenting below.

Update:  The HS_Risk_UK property set was missing three properties (AssociatedProduct, AssociatedActivity and AssociatedSpace).  This was done intentionally to be automated during export into COBie, but my method is incorrect as they are mandatory fields.  They have now been included in the Pset Definition file, screenshot and downloadable files.  Thank you, Nick Nisbet.

PLQ 3.3 – Measured Maintenance

Hello BIMfans,

Now that my COBie has been validated during COBie Culmination, it is time to put that information to use.  When Configuring Costs, I mentioned Jonathan Hewitt of Hewitt Consult Limited had kindly offered to put my information into CostX to produce a preventative maintenance schedule.


Not only has he produced my schedule, but by dealing with the interoperability issues, I have managed to get some useful insights into how my cost information should be managed.  Included below are the steps taken to produce my preventative maintenance schedule.

Review of Pre-embedded Costs

When producing COBie, I made a point of including as much information as I could, which included Type.ReplacementCost.  However, there is a problem; costs change.  Using services like CamelCamelCamel, this becomes clear.

Camel camel camel camel camel … chameleon?

For example, over four years, the Nest Learning Thermostat’s price fluctuated from £312 to £99; who knows what the replacement cost will be in 15-20 years’ time?  Jonathan told me that Quantity Surveys/Estimators normally use schedules of rates when producing cost plans; typically agreed at the start of a project.  For the purposes of this exercise, Jonathan produced a schedule of rates using my replacement costs and uploaded it to CostX as a rate library.

Review of Uniclass

After I spent some time Understanding Uniclass, I applied Uniclass 2015 to all of my manageable assets.  I thought that this information would be useful when calculating my maintenance schedule, as the respective NRM3 codes could have been applied based on the Uniclass 2015.  However, we came across a problem, when the DWFX was exported it was missing my Uniclass 2015 classifications.


While my assessment information, BS 8541-1 aligned object names, IfcGUIDs and IfcNames were all exchanged without an issue, ClassificationForObjects was blank.  Now luckily, because I had named my objects following ISO 4157-1 as outlined in Naming Omnibus, Jonathan was able to work without Uniclass 2015 (Phew!).  This problem didn’t occur when we tested this afterward using my IFC files. Perhaps CostX should recommend IFC over DWFx instead?

Model Mapping

ModelMappingWhen I asked for this preventative maintenance schedule, I was quite clear that I wanted it structured by AssessmentCondition.  My plan is to deal with all poor items this year, and then move on to less critical elements over the next three to five years.  To do this, Jonathan had to apply model mapping, which he explained as:

 “[Model mapping is] a powerful tool that allows you to dictate what information is extracted from the model by creating “dimension groups”.  Using conditional formulas, I was able to sort information based on each of the possible assessment ratings:  Adequate, AsNew, Good, Poor or Very Poor.  This provided the breakdown required, and formed clear groupings that could be calculated independently.  This could only be achieved thanks to the consistency within Dan’s information, as the use of element GUIDs”

Jonathan stressed to me the importance of having a globally unique identifier (GUID) within CostX for each element to enable the use of rate libraries and systems.  As such, I asked that for the IfcGUID to be used.  However, this posed a problem initially as I had exported the DWFx before my IFC, meaning that some IfcGUIDs were missing (oops!).  Once I had resolved this, each element had a unique identifier.

Completing the workbook

Finally, now that the information had been structured, my preventative maintenance schedule could be produced.  Luckily, due to the efficient file sizes I maintain, this process took no time at all.  As you can see the information has been summarized based on the assessment rating and then itemized in full.

This document is exactly what I need to consider what maintenance to undertake first.  I really enjoyed working with Jonathan and apparently, he did too as I he was kind enough to leave me a Testimonial:


And there we have it.  Thanks to the help of Jonathan and Hewitt Consult Limited, I now have a fully costed preventative maintenance schedule.  This exercise has been really educational and has changed my perspective of how I plan to manage my graphical models.  Increasingly I have been putting more information in, but this isn’t the ideal solution.  For example, Jonathan told me that:

CostX is designed for Quantity Surveys/Estimators to do what they’ve always done; take off quantities and undertake cost planning using rates built up from first principles but in a quicker, digital way.  Through tools like CostX, rate libraries could be shared for benchmarking purposes.  Static cost information is OK when you have agreed a target cost on a project and you want to use it for valuing work done or negotiating change control. Those same static costs are useless later down the line when the asset is in operation; costs change!  If a dynamic cost link could be made, this would be useful and powerful for asset management”

If tools like CostX are being produced to empower estimators, then there isn’t much of a benefit in the exchange of static, and often out-of-date cost information.  So from now on when it comes to costs I will do what I always use to do, just leave it to the Quantity Surveys/Estimators!

Note:  As a result of this insight, I have now removed all cost information from my information model.

As you can see, as we have now attributed costs to my assets, I have completed another Plain Language Question.  Fantastic, PLQ 3.3 is complete!

Operation and Maintenance

  • 3.1 What are the sizes and condition of the windows & doors?
  • 3.2 What assets are in a poor condition?
  • 3.3 What costs can be attributed to my assets?
  • 3.4 What are the most cost effective thermal improvements that could be undertaken?

Now that my preventative maintenance schedule is complete, it is time to look at my final Plain Language Question, can I use this information to inform how to improve the energy efficiency of my home?

Note:  If you have any comments regarding my preventative maintenance schedule, then please let me know either on Twitter, or by commenting below.

PLQ 3.3 – COBie Culmination

Hello BIMfans,
Those of you who have been following this Blog will know that producing good COBie has been a persistent goal of mine.  This goal may sound simple, but it wasn’t.  Due to the current state of software, the delivery of well-structured information isn’t a one-click activity (one day we’ll have that magic COBie button…one day).  When producing information to manage my home, I have been careful to ensure that the properties and attributes I’ve used have been structured to suit the available British, European and International Standards which are:

Because of my allegiance to the Standards, I’m confident in the quality of my work.  However, I can’t be sure.  Most methods of producing COBie do not incorporate verification, a method of testing that the information has been formatted correctly.  Meaning that while it might save like COBie, and look like COBie, it isn’t necessarily COBie.  My process of using an IFC rendition to produce COBie through xBIM has this problem.  Thankfully, a follower came to the rescue; John Ford.

Look at this BIM model!

John is the senior business information development manager at Carillion Plc.  If the name seems familiar, it’s because he is quite active on Twitter and is one of the most active participants in the LinkedIn COBie forum.  One of  John‘s many key roles is the validation of COBie using Carillion‘s preferred COBie quality control plugin, the COBie QC ReporterJohn contacted me and kindly offered to verify my COBie (I think I nearly bit his hand off!).

Note:  Anyone (I mean anyone) is free to take files off this blog and use them for whatever purpose they like; they are on creative comms for a reason.  Please play with these files and let me know how to improve them.

John provided a series of reports created by the COBie QC Reporter, filled with useful information that tabulated the findings from each sheet, like the one shown below.  Reading these reports I discovered that my COBie had failed!


Full disclosure, I knew they would fail.

Back when I looked at my Data Security, I opted to use ‘redacted’ as my email address.  Because of this, I was producing an error each time my email address should have appeared.  However,  John also found a few other errors that I wasn’t expecting.

  • Email address.  I was also getting a second email related error.  The other was that I incorrectly used ‘n/a’ when I didn’t know the warranty guarantors of my components.  To resolve both of these used ‘redacted@bimblog.house’ and ‘unknown@bimblog.house’ respectively.
  • Model Number.  I didn’t realise that model number had to be a value other than ‘n/a’.  Because my home has a lot of missing information, I don’t know the model number for most components.  To resolve this I used ‘unknown’ instead.
  • Warranty Start date.  No components in my architecutal model had a warranty start date (ooops!). To resolve this I added the attribute as required.
  • Duplicate Types.   After exporting, duplicate types were appearing.  On investigation it turned out to be an issue with Revit and the way it handles instances.  Types were duplicated if their default height or their orientation had changed.  I have been in contact with Autodesk who have recognised the issue and are looking into it.
  • xBIM.  Due to my use of Revit to IFC to xBIM, some of the default cells were not being completed such as Attribute.Unit, Attribute.AllowedValues and Space.Floor.  In addition, some components would appear without their type, and vise-versa.  To resolve these I modified the information in post (shown in red).  I will be raising these issues with xBIM in the new year.
  • Assemblies.  My assemblies were not exporting as expected; causing validation issues.  To resolved this, I omitted them from the report.
  • Picklist.  To date I had been lazy and hadn’t written my own picklist.  As such it was causing some validation issues.  To resolve this I just sat down and wrote the damn thing.

Once I had resolved these issues,  John kindly re-verified my COBie through the COBie QC Reporter and found zero errors; woohoo!!  As you can imagine I was pretty chuffed and had to tweet about it:

You can access my validate COBie here:

I wasn’t the only one who was impressed; John was quite impressed too.  In fact, he was so impressed that he left this kind testimonial:


Note:  Other testimonials for this blog can be found here.

And there was have it.  Throughout my professional career, I have always valued third-party validation.  It’s one thing to say it, it’s another to have someone else prove it.  Thanks to the kind help of John, we’ve managed to prove that my COBie not only walks the walk; but also talks the talk; fantastic.

As you can see, it has taken a lot of effort to ensure that the information I have produced is correct, and this has only been for a small Victorian mid-terrace. My effort would pale in comparison to the effort needed to deliver COBie for a multi-million-pound central government BIM Level 2 project using today’s software.  If we expect ‘proper’ projects to do the same, the methods we use to produce COBie needs to improve.

Operation and Maintenance
3.1 What are the sizes and condition of the windows & doors?
3.2 What assets are in a poor condition?
3.3 What costs can be attributed to my assets?
3.4 What are the most cost effective thermal improvements that could be undertaken?

Now that I have perfected my COBie, it’s time to find an asset management system to export this information into…

Note:  If you have any comments regarding my COBie and the validation process, then please let me know either on Twitter, or by commenting below.