SAPS and accredited construction drawings.

[Big Jimbo]

So you want to build a new house. You would like to do slightly better than Wimpey Homes. Before the new 2022 part L came into force, you could get details of how to improve your many thermal bridges from sources such as BRE, Labc. Energy saving trust, planning portal. They had best practice, drawings and calculations that were accredited, and gave improved psi values that a saps assessor could use to bring up your saps score rather than using the default values for all your leaky areas, such as around your windows, floor to wall junction etc. Since the introduction of the new 2022 part L, these have been withdrawn. So if you now want to make improvements there are no accredited details to follow and you are expected to get thermal modelling done on these area. Even if you do that, they wont be accredited, so cant be used in your saps calcs. 

 

Today i spoke to 3 different saps assessors who all told me that until some new accredited details are approved and done that everybody is just going with cramming a load of solar on the roof. What happened to fabric first ?

So like most on here, trying to do a bit better. Looking carefully at all your rubbish thermal junctions. It would appear to be a waste of time in relation to your saps score.

Therefore, should i just build to crappy standards, and stick some extra solar on like the big boys seem to have started doing. I will get a better looking saps ticket.

Are we starting to go backwards ?

[JohnMo]

I assume you know your build method?

 

Read up on passivhaus build standards to get an appreciation of what is good or bad.

 

 

[nod]

You need to treat the sap report as a guide Whilst building control will do what they can to check that you are following everything that is in the Sap 

Quite a lot is on trust Especially if your above the bare minimum that’s required 

 

It well documented that my wife and myself hate PV panels on a roof 

Unlike this time planners were insistent that we installed them 

Estimated cost 7-9 k Estimated Annual saving per year £250-300 

Instslling PV added 2 points to our sap score installing MVRH took 2 points away We ignored planners and didn’t install PV and spent the saving on extra installation 

 

The new home sites that I work on in my day job Tend to score 2 in airtightness test It’s about 4 years since I’ve seen one being carried out 

There meant to do 1-7 But most seem to be done as a desktop study 

I would image there Sap reports are the same 

[Big Jimbo]

I'm no expert, but i have been around the building industry for 30 years. Interested in the process of building since i was about 10. I'd like to think i know, although not claiming to be an expert, about attention to detail, thermal bridging  etc. The point i was trying to get across was that if you are not going to get any credit for "doing better" than why bother. I'm not talking about the self builder on this forum. Move the small or large developer, chucking up houses to sell to the poor general public. I believe @nod is currently marketing for sale One of his previous self builds. From memory the only thing people were interested in were the kitchen tap, and hob.  Sad, after the effort he made to do "better". If the big boys are not going to get any credit for spending extra money on improving thermal junctions, they will opt for the cheapest things to get the best saps score, which might not be the fabric first approach

[ADLIan]

Following last changes to the Regs many manufacturers have introduced their own psi-values that can be used in the SAP process in place of the old ACDs. Elmhurst keep a register of these companies that assessors may use. Available to Elmhurst assessors - copy attached. Remember under the new Regs photo evidence is required to show the exact detail has been followed on site

Elmhurst Thermal Bridging Scheme List v3.xlsx

[nod]

10 hours ago, Big Jimbo said:

I'm no expert, but i have been around the building industry for 30 years. Interested in the process of building since i was about 10. I'd like to think i know, although not claiming to be an expert, about attention to detail, thermal bridging  etc. The point i was trying to get across was that if you are not going to get any credit for "doing better" than why bother. I'm not talking about the self builder on this forum. Move the small or large developer, chucking up houses to sell to the poor general public. I believe @nod is currently marketing for sale One of his previous self builds. From memory the only thing people were interested in were the kitchen tap, and hob.  Sad, after the effort he made to do "better". If the big boys are not going to get any credit for spending extra money on improving thermal junctions, they will opt for the cheapest things to get the best saps score, which might not be the fabric first approach

You are correct Jim 

Weve have 14 viewings All are professional Doctors and consultants 

One conveyancing solicitor also 

none have asked about levels of insulation Let alone Sap rating or air test scores 

Yep boiling tap and German kitchen One has been back with a builder who checked that I’d self installed the treatment plant and asked to see the foundation drawing and talked about extending the back of the house 

I pointed out the great lengths I’d gone to to prevent thermal bridging 

He replied Ooook I think he was interested but didn’t show it 

Not one has even asked if the boiler is A rated 

 

Being a couple of miles away from a hospital I pretty much expected meds to be our core market and while I didn’t expect to besieged by Echo warriors I am convinced that had we built to passive standard The response would have been the same 

 

[Big Jimbo]

Thanks @ADLIan i will take a look later.

[Dave Jones]

heres a couple

 

https://www.labc.co.uk/professionals/registration-schemes/registered-construction-details

 

https://tools.bregroup.com/certifiedthermalproducts/

 

[Big Jimbo]

The Labc construction details are not to be used after 2021.It say that on the link @Dave Jones

[Big Jimbo]

@Dave Jones i will ring BRE in the morning. from my reading today, i'm not sure there details are still in use. The problem with some of the manufacturers published psi values are not full solutions for whole elements, but rather specific products. I will also speak to my saps bloke . One of my issues for instance is that due to my cladding on the top half, i can't get my windows 30mm into the insulation, due to the depth of cills available. Therefore, even though i have a method to counter this, unless i have my solution thermally modelled by somebody who will be accepted by saps assessors (prob BRE) Then i will get no sap calc benefit, and will have to put up with the default element. In view of @nod experience, i think i might just save my money, and spend it on a boiler water tap. I have spent most of today reading on a lot of forums about saps, some of them with contributions for sap assessors. The general thoughts are that even the new sap 10.2 are not fit for purpose.

[nod]

1 minute ago, Big Jimbo said:

@Dave Jones i will ring BRE in the morning. from my reading today, i'm not sure there details are still in use. The problem with some of the manufacturers published psi values are not full solutions for whole elements, but rather specific products. I will also speak to my saps bloke . One of my issues for instance is that due to my cladding on the top half, i can't get my windows 30mm into the insulation, due to the depth of cills available. Therefore, even though i have a method to counter this, unless i have my solution thermally modelled by somebody who will be accepted by saps assessors (prob BRE) Then i will get no sap calc benefit, and will have to put up with the default element. In view of @nod experience, i think i might just save my money, and spend it on a boiler water tap. I have spent most of today reading on a lot of forums about saps, some of them with contributions for sap assessors. The general thoughts are that even the new sap 10.2 are not fit for purpose.

Unfortunately You are right 

They are simply not policed and the final as built sap is a joke It is all based on what you tell them 

They accepted estimates as proof of U values for windows and doors 

[Big Jimbo]

Just now, nod said:

Unfortunately You are right 

They are simply not policed and the final as built sap is a joke It is all based on what you tell them 

They accepted estimates as proof of U values for windows and doors 

I think i will simply do what i need, to get the required pass. spend my money on sexing up the visuals. As i have 3phase, i might have a look at putting a quick electric charging point in (car charger is a condition) That might get an oooooooooh. 😂

[ADLIan]

Manufacturers offering psi-values will obviously promote their own products. The 2D thermal modeling of the junctions is time consuming and complex - I undertake them for the insulation company I work for as part of our technical and sales package. The problem with some current psi-values is to be acceptable under the current Building Regs and SAP 10 they must be done to the 2nd edition of BR497. Many older values were to the 1st edition and these can only be used for the previous Regs and SAP 2012.

Note photo evidence is now required for many aspects of the build so the Regs have tried to close this loophole. I cannot say how successful this is or will be as I'm no longer an accredited SAP assessor. I baled out as I would be spending too much time chasing for these photos and other evidence and then being cast as the bad guy when they're not available (which is a BR failure!) or show a different insulation/thickness, etc, etc and the 'as built' potentially fails.

[Big Jimbo]

@ADLIan No i understand that it will be costly. It's just a shame, as previously there were various drawings available, that if you followed you would get some credit for. seems a great shame that they did away with them, and now there is basically nothing that has replaced it.  I wouldn't expect manufacturers to have to produce the drawings that show there products in 20 different uses combined with other peoples products. I don't think it is unreasonable for someone like BRE to have a set of standardised drawings that can be followed. I have got 5 drawings for details of thermal bridging. I shall follow them anyway, but seems a shame that because they are not accredited junction details that will make a big difference to my thermal losses, they effectively are worthless. I am going to speak to BRE today to find out how much it will cost for me to have them looked at and accredited. I shall report back.

[ADLIan]

The BRE is a commercial body and will want payment for a new set of Accredited Construction Details - I doubt the Govt is minded to fund this sort of work. There is no need to be 'accredited' or 'approved' to undertake psi-values - the requirement is simply to be 'competent' - a discussion to have with your BCO (if he knows what a psi-value is!).

 

Will be interesting to see what the BRE have to say.