No bombshells in the new SAP

Dyfrig Hughes

So, the proposed update to SAP (SAP 2012) has at last been released by government. Well, having spent much of the past week pouring over the proposed changes, I have to say that there’s not a lot in there to get excited about. As hard as I tried, I could not find any bombshells for housebuilders. This is in stark contrast to SAP 2009 when builders discovered that they would need to insulate and seal party walls as well as start paying serious attention to non-repeating thermal bridges. Instead, the proposed SAP 2012 update is very much a tidying up operation with a bit of underpinning for key government policy areas such as carbon reduction and the Green Deal.

To discover the full remit of SAP 2012, read our 5 page summary of the changes:
SAP 2012 in a Nutshell

The most significant change, certainly from the perspective of the Assessors and the house builders, is around thermal bridging. This was the aspect of SAP 2009 that caused most grief as it involved significantly more work for Assessors and much more attention to detail for house builders. With SAP 2009, SAP Assessors had to become familiar with the various types of junction, learn to measure their lengths and figure out how to deal with features not explicitly addressed in the SAP 2009 document such as dormer windows. This also brought with it commercial challenges as it significantly increased the time taken to carry out a SAP assessment.

Well, SAP 2012 addresses some of these non commercial issues head on by dealing explicitly with things like dormer windows and roof rooms. It also introduces new junctions that were oddly missed out in SAP 2009, such as roof to roof junctions. However, it is unlikely to ease the commercial pressures.

One thing that’s easy to miss though, is that all mention of thermal bridging ‘confidence factors’ is gone from SAP 2012. These are the factors (+ 0.02 or x 25%) that were to be applied to psi values if there was no evidence of on-site quality assurance checks having been carried out. This suggests that the Accredited Construction Schemes that have been under discussion for the past 18 months or more might bite the dust when the Part L 2013 consultation comes out.

The shift in SAP 2012 to support government policy regarding greenhouse gas emissions is a change to the way average carbon emissions are calculated, most notably to include emissions associated with transportation of fuels. Then there is the output of both 3 year average figures and 15 year average figures, to support both short and long term carbon policy. Not to mention the additional output of methane and nitrous oxide, the other main greenhouse gases.

And then there is the Green Deal, where the key thing is to be better able to estimate fuel running costs and savings from installing energy saving measures. Here the emphasis is on improved calculations that take into account regional climate such as external temperatures and windspeed (for space heating) and solar radiation (for solar thermal and PV). However, these changes will not affect either Building Regulations or SAP ratings.  

To discover the full remit of SAP 2012, read our 5 page summary of the changes:

SAP 2012 in a Nutshell


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