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.

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.

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 – Configuring Costs

Hello BIMfans,
After ensuring that my I have as much information possible about my managed assets, I think it is time to cost up my preventative maintenance schedule.  To do so, I have enlisted the help of Jonathan from Hewitt Consult Ltd. who has kindly offered to undertake the cost estimating on my behalf.

This cost exercise as bean a long time coming….

So, the first question I asked was:

“What do you need from me?”

To assist with the cost estimation, I wanted to ensure that the information I was providing was as suitable as possible.  I initially offered my IFC files, but I was told by Jonathan that while CostX could import IFC, they advise that the most optimal file format is DWF or DXFx.  As a further (subtle) hint, I was also given a copy of the CostX Drawing File Optimization Guide.  This document outlines how my information should be structured to ensure the information can be imported into CostX correctly covering the following areas:

Export Settings

The preferred export format into CostX is a multi-sheet DWFx.  This is done by setting up a 3D view which includes all of the required objects ensuring that there is a sufficient level of detail applied to the view.    In addition, they recommend that the view’s graphics are set to hidden line.


Optimization required?  New view created A-Zz_70_05-M-CostX

Project Units

Because CostX calculates quantities using the exported base values, all project units need to be sufficiently accurate (at least millimeter accurate).  If these values are rounded off then they will affect the exported quantities they support.  For example, my dining room at 3.46 x 3.56m would export an area of 12m² (3x4m) instead of 12.89m².  Luckily for me, I am already using a sufficient degree of accuracy.

Optimization required? None

Family Naming

As CostX sorts objects according to their family names, it advises that descriptive family naming is used.  Thankfully, as you’ve seen from Naming Omnibus I have adopted the BS 8541-1 and ISO 4157-1 naming conventions I have quite descriptive names already.

Heisenberg “Say my IfcName”

Optimization required? None.

System Assemblies

When assemblies, such as floor, walls, and roofs are exported into DWFx, they appear as a single homogenous object.  To resolve this, CostX suggests that further detail is provided within the objects’ description, additional information is provided through detail sections, or Revit’s parts function is used.  However, as we are producing a maintenance schedule, this level of granularity shouldn’t be required.

Optimization required? None.


To ensure that room information is exported, CostX advises that rooms are represented within the native model and that the setting “Rooms and Areas in a separate boundary layer” is checked to export this information.  As my native model already has rooms, I just need to ensure that this setting is correctly selected.

Optimization required? Export setting “Rooms and Areas in a separate boundary layer” to be checked.

Shared Parameters

To further optimize the sorting of information, CostX advises that the additional parameters QSID and ELEMENT CODE may be included.  However, as I have not been asked by Jonathan to include and populate these parameters, I haven’t.  In addition, CostX advises that parameters should generally be added as instance level but as this would affect how my IFC files are produced, I will not be changing this.

Optimization required? None (due to awkwardness).

Once I exported the DWFx, I checked it within Design Review.  The file appears to contain all the information I expected.  So, the next step is finding out what Jonathan thinks of it, as well as whether or not he is able to use the information within to cost my preventative maintenance schedule.


You can access the DWFx from here


And there we have it.  By using the guidance I was given on how to optimize my information, I now have a container ready to be exchanged for costing.  By listening to Jonathan’s needs, I have (hopefully) managed to produce suitably configured information in the best possible container.

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 updated my components, it’s time to bring all my information together and complete my preventative maintenance schedule…

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

PLQ 3-3 – Kitchen Konundrum

Hello BIMfans,
Recently, I came to the realization that as I never received any product information about my kitchen when I bought the house, my information model is missing some details.  So, I decided to see what information I could find using my whits and a little ingenuity.

First things first, I needed to work out who produced my kitchen.  After failing to find the range comparing materials on Google Images or checking Pinterest, I decided to use my detective skills and carefully inspect my kitchen units for hints.  While inspecting, my keen detective senses alerted me to a clue.

Detective Level:  Maximum

Ok…now that I know it is a Howden’s Kitchen, I thought that the hard part was over; oh no.  After struggling to find contact details for Howden’s Kitchens, I rang my local branch who informed me that as I was not the account holder (the previous owner the house is) they could not provide ANY information (Harumph!)  So, I did what any person would do in this situation, moan on social media I tried Google to see what I could find.  NOTE:  Typing “inurl:pdf” into Google makes this kind of search A LOT easier.

While looking through the myriad of links Google provided, I found a Howden’s trade catalog.  Within, it included everything I needed.  While it appears that some of my components have been discontinued, I could find equivalents to be included within my information model.

NOTE:  As the purpose of the information is to deal with replacement, or maintenance and repair, using information about an equivalent product seemed much more practical than sourcing information about discontinued products.

Some might say this blog has sinked to new lows…

So, all I that was left was updating my information model…

Work Surfaces

In my home, I have two 38mm bullnose matt walnut block laminate work surfaces. Luckily, my graphical model already included work surfaces with the correct thickness and profile but had mislabelled the laminate as Iroko as opposed to Walnut (Idiot!).  I have now updated my material information to suit.



In my home, I have 1.5 bowl sink.  Looking into the Howden’s trade catalog, I found the closest equivalent, the Lamona standard 1.5 bowl sink (Model reference: SNK5131).  In addition, I also found an equivalent mixer tap (Model reference:  AP4805).   In this situation I have teated my tap like I would ironmongery and instead of giving it it’s own component have referenced it within it’s ‘parent’.  Here you can see I used the Type.constituents COBie property associated to my sink component to capture the tap model reference.



In my home, I have a Lamona single fan assisted oven (Model reference: LAM3301), Lamona gas hob (Model reference: LAM1001), black enamel supports (Model reference: LAM1003), and the Lamona standard chimney extractor (Model reference: LMS2400). While updating this information I thought it also prudent up give their graphical representations a spring clean while keeping the detail low in line with my BIM Execution Plan.


If only my kitchen always looked this clean


Finally, I have a series of kitchen units I have originally named BBH_Furniture_KitchenUnit.  However, now that I know they were produced by Howden’s Kitchens, I can update their file, type, and component names to suit.  In addition, as the catalog has done I have split their names into base units and wall units to give me:

  • Howdens_Furniture_BaseUnit
    • BaseUnitType
      • BaseUnit
  • Howdens_Furniture_WallUnit
    • WallUnitType
      • WallUnit

Synthesizing all of this information together has vastly improved the quality of information I maintain about my kitchen.  So much so that I was able to produce a kitchen assembly drawing using this information.

Full-size drawing can be accessed here.

And there we have it.  By using my keen (cough) detective skills, I have now properly identified all of the components in my kitchen.  This means I should now have all of the information I need to apply costs to my preventative maintenance schedule; fantastic!

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 updated my components, it’s time to bring all my information together and complete my preventative maintenance schedule…

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

Size Doesn’t Matter

Hello BIMfans,
As you know, I am currently using the Asset Information Model I produced during this blog to manage my home.  So far my information model has been used to support day-to-day operation, minor works such as getting my gutters and fascia replaced, as well as product registration and replacement, in line with my  Model Purposes and Data Requirements.  But has it been worth it?  Well, let’s try and work it out (don’t worry, I’ll do the sums).


Well, first thing’s first, how much did my information model cost? Well, because I did it myself, there isn’t really a figure I can apply.  However, as it has taken a while to produce, instead, I decided to use a different form of currency; minutes instead of pounds (after all, time is money!).

Quite often when talking about the blog I am asked “How long did it take to model all that!?”, and while it has taken over a year to produce, it was done in my spare time, with a lot of trial and error.  If I lost all of this information (please, please, NEVER let this happen!) I believe I could reproduce everything within four working days (1800 minutes).  This aligns with a New Zealand case study that took three days to model and write-up social houses.  So the real question is:

How long will it take for my information model to save me 1800 minutes?

My plan has always been for my information model to be useful, so I am confident that there is a return on investment; I just need to work out how long it is.  When I wrote my Model Purposes and Data Requirements, I decided that I would use my information model for the registration, operation, maintenance, repair, and replacements.  So let’s see how it has helped in those areas.


While trying to write this post, I discovered that I have registered a surprising number of components.  Excluding loose furniture, I have registered 104 (yes, 104) manageable components and assessed their condition.

Traditionally to keep track of the condition of these components, frequent property condition surveys would have been needed.  While I can find examples from several housing associations who undertake annual condition surveys, I have decided to instead follow Cardiff Council‘s own Asset Management Plan; using their conservative 2-3 year programme.  Having done surveying in a past life, I’m confident that to survey and capture all the relevant COBie information for these 104 components would take a day and a half (average of 6 minutes per component), whereas updating my information model would only take me half a day.

Having this information as the basis really speeds up the surveying of my home.

This results in a saving of 450 minutes every 2.5 years, or an annual saving of 180 minutes. (This alone would provide a return on investment within 10 years)

Operation, Maintenance, and Repair

Working for BRE, I’m sure you won’t be surprised to hear that I want to reduce my home’s carbon footprint.  A goal of mine is to improve my home’s EPC score from a D (65) to a B (86).  To do so, I am going to need some tradesmen every now again (but never again from Rated People, grrrrr).

My information model has been great for solving operational problems.  For example, when I had my gutters and fascia replaced, the quoting tradesmen raised an issue.  I live in a thin terrace house, with no external access to the garden.  After quoting for the work, they each wanted to re-visit and check whether their six metre scaffold pipes could get through the house.  I didn’t want to book another half-day off work, so I instead used my information model to demonstrate that it was possible.


Once I proved this, I was happy to accept accountability that the scaffold would fit, and saved myself from having to book a half-day off work.

If I assume I’d get tradesmen in every two years, this results in a saving of 225 minutes every two years or an annual saving of 112 minutes. (This alone would provide a return on investment within 17 years)


As I’ve mentioned, I have 104 manageable components, each of which will ultimately fail and need to be replaced (What Asset Managers would call a ‘trigger-related event’).  So I have done some research and calculated my components’ service lives.  For example, my two extract fans, have a pitiful service life of 10 years, while my internal doors have an impressive 100+ years.  Whenever I need to replace any of these components, I will be saving time.

Picture this scenario, while I am out shopping I suddenly receive a call.  My wife has rung to say that on her way out she noticed a bulb had blown in the living room, and asked if I could buy a new one on my way home.  There is just one problem, I cannot remember whether my living room pendant takes an Edison (E27) or a screw fix (E14) bulb.  So I have two options:

  • Option 1:  I drive home (30 minutes), grab a chair and check the bulb (2 minutes, working from height), drive to B&Q (30 minutes, other hardware stores are available), buy the new bulb (5 minutes), drive home (30 minutes), and then install the new bulb (2 minutes, working from height) for a total of 99 minutes.
  • Option 2: I check my information model on my phone and confirm the bulb type (2 minutes), buy the new bulb (5 minutes), drive home via B&Q (30 minutes, other hardware stores are available), and then install the new bulb (2 minutes, working from height) for a total of 39 minutes.
The Value of Asset Capture
Oh look, my pendant has an E14 to E27 adapter on it, that means I could have bought either!

So by referring to my information model each time I replace a component and purchasing replacement on my way home, I am saving myself 60 minutes and halving the amount of time I am working from height.  While an hour might seem excessive, this is quite conservative compared to the case study on the BIM Task Group Website from Manchester City Council, where the Bulb Replacement Case Study reports a saving of 8 hours (480 minutes) per replacement.


Based on available service life figures I found online, I produced this table which groups components by their IFC type, and shows an annual saving of 205 minutes. (This alone would provide a return on investment in under 9 years).


Having looked at my various Model Purposes, I have come up with the following annual return on investment thanks to the efficiencies I have gained through using my information model.

Registration = 180 minutes
Operation = 112 minutes
Replacement = 205 minutes
Total = 497 minutes

Which, when compared to a production time of 1800 minutes, gives a return on investment in 3.62 years.

And there we have it, by using conservative figures a reasonable return on investment could be calculated.  When you consider that this excludes all loose furniture, and does not factor in any accidental damage, my information model will have saved more time than that it took to produce in little over three and a half years; Fantastic!

Note:  If you have any comments regarding other efficiencies I could factor in, or the figures I have used to calculate my ROI, then please let me know either on Twitter, or by commenting below.

PLQ 3.2 – Classical Conditioning

Hello BIMfans,
When I made my information model I didn’t want it to be just for show, it wanted it to be a (useful) tool to manage my home. That is why I was very pedantic fussy particular about what information I needed by forming several Plain Language Questions, my Model Purposes, and my Data Requirements. Since this blog’s outset, one clear output I had in mind was to use the information model to manage any repair or replacement work needed within my home. To do so, I will need to form a preventative maintenance schedule; time for some Classical Conditioning!

I’m no Pavlov but I am known to drool over good information.

When I first wrote my Data Requirements, I was keen to incorporate a way to capture the condition of each of my components. The problem was, I needed a way to record this consistently; luckily for me, there is a way to do this.  BS 1192-4, the British Standard for COBie, includes some additional attributes under table 14, which are also included as part of IFC4 Schema, under the Pset_Condition property set.

AssessmentDate, when the assessment was completed YYYY-MM-DD;
AssessmentDescription, qualiative description of the assessment; and
AssessmentCondition, the condition:  Very Poor, Poor, Adequate, Good, or AsNew.

So, a plan was formed.  When I produced my components, each of these attributes were added to the one I intended to manage. As a result, this information appears in each of my graphical models, IFC exports, and COBie files (the joy of a single source of truth).  As the majority of these components were assessed when Chris John undertook a (very thorough) property condition survey before we bought the home, there isn’t much additional information to be collected.  The only exception being new items such as my Nest thermostat and Philips Hue bulbs that have been installed since.

As you can see, this window was surveyed August 2015, as part of the property condition survey, and it’s in a pretty good condition.

Using these assessment attributes, I can manage each of these components and develop my preventative maintenance schedule. For example, using the AssessmentCondition attribute, I can filter and identify any Very Poor or Poor components. Of the 100+ manageable components I have in my home, I can use Revit‘s scheduling function to filter this information down to just those components and form a manageable schedule.

NOTE: I could have done this using my COBie file, but I won’t.  COBie isn’t a data management tool. Until I acquire an asset management system, using the information embedded in my graphical models, as I have done, is the best solution.

By federating my models, I can create a single schedule showing all of the Very Poor and Poor components in my home.

And there we have it.  By using the information that I have already populated within my information model I was able to create a preventative maintenance schedule highlighting what components need to be repaired or replaced. This means that PLQ3.2 is complete; Woohoo!

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 what needs doing around my home, I wonder how much it’ll cost to fix…