Adoption of BIM for house builders requires a unique approach, says Nigel Walley, founder of proptech start-up Chimni.
House building is arguably the BIM industry’s most notable failure to date, with only those parts exposed to public sector procurement having made significant progress.
During 2014, I was involved in setting up the BIM4Housing working group. As part of the scoping process, the founding group travelled round the UK holding seminars and workshops with house builders and contractors looking at the issues of adopting BIM.
What became clear from these sessions was that developers and contractors felt that home building was different to many other construction sectors in its exposure to BIM, and there were hurdles to adoption that would need a unique approach.
The first issue raised was lack of scale. The house builders felt that BIM came into its own with projects of significant scale, but benefits were harder to realise for smaller-scale projects. While the UK has a small number of very large house builders, housing is in large part an SME Industry. Outside of the top 10 housing companies, the average size, and number of units built annually, plummets.
A second issue, related to the issue of scale, was standardisation. Our participants felt that BIM’s advantages were greater where the multiple use of standard designs could allow BIM to be part of a broader standardisation and automation process.
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While the larger house builders where able to achieve this, it was more common for small and medium-sized home builders to be dealing with fragmented and irregular land banks with a need for greater variations in design layouts. This was also an issue for innovation around offsite and modular construction.
The participants also flagged up the difficulty in ensuring that the final built home conformed exactly to the CAD or BIM models they were based on. House builders spoke about the leeway they have to give to their onsite teams in procurement and final build decisions.
Often the freedom to source materials locally if necessary, or respond to site conditions dynamically mean that the CAD model is treated as a statement of intent rather than a rigid construction guide. The idea that a BIM model would be incorporated into a digitised construction process for these developers was fanciful.
Finally, the lack of a fourth stage for BIM was highlighted as a problem. One of the key benefits of the transition to BIM, and one of the client drivers to architects and contractors investing, is the ability to hand BIM data and models over to owners at the end of the construction stage.
In housing, the benefits of this stage are hard to pin down. In structured, social housing there are FM models emerging that can use BIM output. However, the wider housing culture has yet to address this potential source of benefits. It means that, for housing, there is almost no client pressure towards the adoption of BIM.
Once again a related issue was the slow progress in creating BIM objects for domestic building materials and products. Because of the lack of pressure from owners and FMs, it was felt that the manufacturers aiming their products at the residential market had done the least to create new information models and BIM data for their products.
None of the issues cited were intended as reasons to avoid adopting BIM. The respondents were clear in their broad intentions to evolve, but were facing commercial and operational barriers that currently seemed too high. More seriously, the house builders saw nothing in the BIM revolution that would help them improve productivity.
This is the reality for the vast majority of small and medium housing developers and the BIM industry needs to address these issues if we are to get the residential industry to catch up with other construction sectors taking a lead in field.
Housing clients need to find a unique approach to digitisation to achieve speedy and frictionless delivery. But we may have to accept that while BIM will be part of this, it may not be core to it as it is in other sectors.