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.

Trigger’s Gutter

Hello BIMfans,
After the best part of a year using sites like Rated People (which found me a dodgy builder), and (which found me a good one), I have finally had some work done to Ty Crempog!!

Due to the terrible join between my square gutters and the neighbours OG gutters, the getter leaks whenever it rains (which as you can imagine, is quite a lot of the time in South Wales!).  This leak soaks our party garden wall, causing damp in both of our dining rooms.  In addition, there was a similar poor join out the front and insufficient ventilation to the attic space.  So to resolve these issues, I formed a plan to replace the fascias and guttering, introduce a ventilated fascias, and resolve these details.  With the work now complete, I have to complete a Trigger-related event to update my asset information.

According to the BRE BIM Terminology tool, a Trigger-related event is:

Response to a trigger and the reflection of the altered state of the asset in the AIM

In a previous post on GUIDs, I discussed Trigger-related events, detailed in PAS 1192-3, and what to do about them in my information model, creating what I called the ‘Sticker Rule‘.  This sticker rule dealt with my own version of the Trigger’s Broom paradox, where I wondered if when I replaced a part of Ty Crempog, should it get a new globally unique identifier or GUID.  I decided that new components need new GUIDs.

If the reference is lost (especially if you aren’t British), watch this YouTube clip.

So then, by following the sticker rule and my Employer’s Information Requirements, I needed to update my graphical model by deleting the existing fascias and gutters and create new instances for their replacements.  But what were they replaced with?

This led to a practical BIM problem:

How do I get my builder (who has never even heard of BIM) to give me good quality information to input into my information model?

Simple, I just asked them.

Now it would have been much easier if South West Fascias had provided me with a Product Data Sheet for the products being used.  A product data sheet, such as those from goBIM by Cobuilder, would have provided me with all the information I needed in either an Excel or COBie format.  A key advantage of product data sheets is that instead of me searching for this information (and being liable for its accuracy), the information could have been provided by the supplier, saving time and reducing my risk.

Look at all those lovely fields of information I could have had access to

Anyway, as this was not something that could be provided, I asked South West Fascias for the product details for what was installed.  They then provided me with details of the merchants and products that were used (AAC Weston for the eaves protection system, fascias, gutters and downpipes, and Travis Perkins for the dry verge system). This information was enough for me to find the products, and extract from these websites the relevant product information I needed.

Principally four sets of products were used along with their associated fixing and accessories:

  • Eaves Protection System
  • Fascia Board
  • Dry Verge
  • Guttering & down pipes

Eaves Protection System

To resolve the lack of clear ventilation in my attic, I opted for an Eaves Protection System (EPS).  The EPS coupled with some boarding will allow me to preserve the attics ventilation strategy when I increase the insulation (to be seen in a future post!). Now the EPS is fairly cheap (£2.45 per unit) and small enough that I wouldn’t bother modelling it.  Partly because of its value, as well as the fact that it wouldn’t really be seen at 1:50.  So, to include information about the EPS without modelling it, I have added some simple product information to my roof’s ‘features’ property.

Through a variation of the BS 8541-1 naming convention, I have included the supplier, type, product, and supplier’s reference in a single field.


Fascia Board

While I was having the work done I opted to have my timber fascia boards removed and replaced with new plastic fascias.  At roof level, these were 150mm Fascia Boards, and around my bay 175mm Fascia Boards.  I updated my fascia profiles in the graphical model to suit, and have included some basic information such as acquisition date, URL, and cost.

Note:  I would have liked to include more information, but due to the way that system families work in Revit, many of the properties that are applied to the families wouldn’t appear.  Luckily for me, these objects aren’t maintainable, so they don’t appear in COBie.

Dry Verge System

Part of the work was also to resolve an issue I was having with my verge, to resolve the poor detailing.  The solution we agreed was to install a dry verge system.  The system chosen was the Easyverge system, a series of interlocks pieces to create a watertight dry verge system as shown.

Dry Verge.jpg
My roof is so happy, you can see it has shed a tear.

Now you would expect a system like this to be difficult to model (and it would have been). However, as my Responsibility Matrix within my BIM Execution Plan only requires a Level of Detail of 3, I am able to represent the system with a fairly modest profile.

See, so much easier when I cheat use appropriate levels of detail.

Guttering & Down pipes

Finally, I needed up remove my existing guttering and down pipes from the graphical model and create new instances for their replacements.  They were replaced with 68mm black round system to match other nearby houses.  As my down pipes are not system families I was able to include much more information including South West Fascias guarantee information, and contact details.

Much better, and more importantly, full of information

And there we have it.  By having work done to my home, I have caused a trigger-related event to occur which has led me to update the asset information model that I maintain.  This means that as my home is modified to suit my needs, I continue to have accurate information at my disposal to be able to make the right decisions about what to do next; Excellent.

Note:  If you have any comments regarding how I represented these new products, then please let me know either on Twitter, or by commenting below.