Failed SAP

[Maria]

Hello all,

 

I have completed my self build, and paid the builders 100% for the works.

 

The building control wouldn't issue the completion certificate without SAP and air pressure test. 

 

I got a call yesterday from the SAP assessor saying the the building failed to achieve the required min.

He said I was ~16% under with the insulation and ~3% under  carbon emissions. 

 

He hasn't issued yet the official report.  He asked me if I wanted him to issue a report. Now thinking about it - do reports get logged in the official register somewhere? Does it make any difference if I have a report or not at this stage?

 

Then he assessor said that my options are either to replace double glazing with triple and put 3kwh PV or put extra insulation in the dormer and 1kwh PV.

The house is completely decorated  painted and the flooring put in.

 

I have no money left at all, and ended up borrowing more just to get to this stage.

 

I didn't have SAP as designed.  Nobody asked about it, and I didn't know.

So I am annoyed that the builders proceeded to build without ever questioning anything, and the BC never flagged it up. I am not a professional developer,  so feel that people who get paid to build and inspect have failed me. I probably wouldn't get anywhere by trying to hold the builders and building control responsible. But would you say I should try to?

 

Any ideas how to get a pass on a budget? Any tips and assistance would be really appreciated. 

 

Many thanks 

[nod]

Ye Pay a £150 to a online company 

and they get you through I’ve said many times before Sap and air testing are a joke and need changing 

I’m not saying you should But if you where to tell the As built Sap accessor that you had upgraded the the insulation He or she has to go off the information that you give him 

He will ask for boiler cert windows etc 

I only had a window quote with the u values on

In fact  I had three so could have used any 

[Jilly]

I feel for you, I've had a lot of those retrospective moments too. I had a design SAP done early on after reading about them and it turns out conversions don't even need one (when I did mine at any rate). Go figure, but that doesn't help you.   Developers often put a PV on the roof without even connecting it up to get the SAP calc correct. 

 

[nod]

I’ll give you an example now 

The area you are looking at is down for 80 mill of insulation the 47 mil insulated plasterboard I’ve gone 80 mil insulation Superfoil another stud 80 mil insulation Then insulated PB 

The sap guy can only take my word that the whole house insulation has been up rated 

[Alan Ambrose]

They do get logged on a .gov site - you can look-up the current sap for any building that has one.

[Alan Ambrose]

Are there any ‘assumed’ values in the current calc - they will generally assume ‘conservatively’ i.e. not to your gain.

 

On a similar note I would double check all their input data. Stuff as simple as GIA can be substantially out. SAP calcs are fairly cheap and therefore often it’s a fairly careless procedure.

Edited July 22, 2023 by Alan Ambrose

[ProDave]

6 hours ago, Maria said:

Hello all,

 

I have completed my self build, and paid the builders 100% for the works.

 

The building control wouldn't issue the completion certificate without SAP and air pressure test. 

 

I got a call yesterday from the SAP assessor saying the the building failed to achieve the required min.

He said I was ~16% under with the insulation and ~3% under  carbon emissions. 

 

He hasn't issued yet the official report.  He asked me if I wanted him to issue a report. Now thinking about it - do reports get logged in the official register somewhere? Does it make any difference if I have a report or not at this stage?

 

Then he assessor said that my options are either to replace double glazing with triple and put 3kwh PV or put extra insulation in the dormer and 1kwh PV.

The house is completely decorated  painted and the flooring put in.

 

I have no money left at all, and ended up borrowing more just to get to this stage.

Fit 4kW PV on roof.  Least intrusive addition and it should get you "over the line"  Not only that, it will reduce your electricity bills for the foreseeable future.

 

DON'T go anywhere near an MCS supplier for the PV.  You just need a roofer to fit the brackets and an electrician to fit the panels and connect it.  I fitted my own for under £2K in parts cost.

 

It is a great shame you did not ask the forum at design stage, we could have given lots of suggestions for how to build a good house.  Sadly it looks as though you will have ended up with something akin to a mass produced developer house, the very minimum insulation and air tightness they can get away with and slap on just enough solar PV to scrape through.  such a house will have higher ongoing heating costs but the developer does not care because 99% of buyers don't care or don't know.  If you are self building you have a chance at the start to do it properly and get something better.

[Maria]

6 hours ago, nod said:

Ye Pay a £150 to a online company 

and they get you through I’ve said many times before Sap and air testing are a joke and need changing 

I’m not saying you should But if you where to tell the As built Sap accessor that you had upgraded the the insulation He or she has to go off the information that you give him 

He will ask for boiler cert windows etc 

I only had a window quote with the u values on

In fact  I had three so could have used any 

An online SAP assessor? Would i still need to provide the specs info that meet the requirements?

What about the air pressure test? Would this need to be taken into account?

Or is this something separate?

Is it possible that a "bad" air pressure test result will be a giveaway of the incorrectly provided specs info?

Hope it makes sense.

 

[Maria]

3 hours ago, Alan Ambrose said:

Are there any ‘assumed’ values in the current calc - they will generally assume ‘conservatively’ i.e. not to your gain.

 

On a similar note I would double check all their input data. Stuff as simple as GIA can be substantially out. SAP calcs are fairly cheap and therefore often it’s a fairly careless procedure.

I haven't seen the report yet. We just discussed it over the phone. I just emailed him to say not to produce the report yet, just in case I go down the route of trying to get someone else doing the report.

Apologies,  what is GIA?

I have a feeling that I mostly failed due to double glazing.

 

[nod]

10 minutes ago, Maria said:

An online SAP assessor? Would i still need to provide the specs info that meet the requirements?

What about the air pressure test? Would this need to be taken into account?

Or is this something separate?

Is it possible that a "bad" air pressure test result will be a giveaway of the incorrectly provided specs info?

Hope it makes sense.

 

Yes they will ask for air test etc 

Most of the companies I work for achieve 2 Which is good considering I haven’t seen an air test being carried out for about five years 

 

The as built final sap is totally reliant on the info you give 

[Maria]

1 hour ago, ProDave said:

Fit 4kW PV on roof.  Least intrusive addition and it should get you "over the line"  Not only that, it will reduce your electricity bills for the foreseeable future.

 

DON'T go anywhere near an MCS supplier for the PV.  You just need a roofer to fit the brackets and an electrician to fit the panels and connect it.  I fitted my own for under £2K in parts cost.

 

It is a great shame you did not ask the forum at design stage, we could have given lots of suggestions for how to build a good house.  

 

 

I, obviously, don't know much about insulation,  but what's been installed didn't seem too bad. 

I double checked with the builder,  and he provided the following;

 

 

1.Walls - 6” timber frame inner leaf with 140 mm timber frame cavity bats insulation, 4” blockwork external leaf with 2 coat sand and cement render, internally vapour barrier and skimmed plasterboard finish.

 

2. Floor – block and beam flooring covered with 1200 gauge radon barrier, topped with 100mm celotex and 22mm moisture resistant flooring.

 

3. Roof - 200mm deep factory made Truss system topped with breathable felt, batten and slate, internally 150mm celotex insulation between the rafters allowing for 50mm airflow between the insulation and the felt, 50mm insulation backed plasterboard to the underside of the rafters with skim finish.

 

Would you expect to see a lot more than this?

Edited July 22, 2023 by Maria

[Declan52]

Did you get a result for an air test??

A better score here isn't hard to achieve with some sealant and a few hours hard work.

 

[ProDave]

This thread shows a real deficiency in English building regulations system, that it is possible to build a house that does not meet the standards, but not find out it has failed to meet the standards until it is finished.

 

The Scottish system is much better.  You have to have a design SAP done before you can get a building warrant.  And then you know if you build the house to what the agreed plans say, it WILL pass the as built SAP, no nasty surprises.

[Maria]

1 hour ago, Declan52 said:

Did you get a result for an air test??

A better score here isn't hard to achieve with some sealant and a few hours hard work.

 

No air pressure test done yet. Will crack on with taping then, and then hopefully,  will get a good result

[saveasteading]

14 minutes ago, Maria said:

Will crack on with taping

And before the air test, close off fan extracts (polythene and masking tape), and close any other vents and gaps. 

And be there during the test. The tester is likely to ask what number your are hoping for, so may  be more helpful if it doesn't quite get there.

 

10 hours ago, Maria said:

to replace double glazing with triple

No that sounds like a bad idea.

 

10 hours ago, Maria said:

feel that people who get paid to build and inspect have failed me

 

Sorry you feel like that, but that doesn't help and probably isn't so. Nobody had overall responsibility but you, so best just get this sorted now.

 

There is lots of knowledge here so keep asking.

 

 

Have you any more info on the input numbers? The advice above is good. Your house is probably much better than many mass development units, but they know the tricks and have influence.

There are lots of tick boxes in the sap assessment where one conservative assumption makes a big difference.

 

I think my next move would be to chat to the assessor again. The windows are not going o be changed. What can be done free or more cost effectively? are there any assumptions you have had to

make that could be looked at again? 

What Air change target am I after?

 

Everyone, does anyone happen to know?.  The suggestion by @ProDave is especially good if this can be fitted later...perhaps very much later.

[Maria]

8 hours ago, saveasteading said:

 

And be there during the test. The tester is likely to ask what number your are hoping for, so may  be more helpful if it doesn't quite get there.

 

Have you any more info on the input numbers? 

There are lots of tick boxes in the sap assessment where one conservative assumption makes a big difference.

 

What Air change target am I after?

 

Everyone, does anyone happen to know?.  The suggestion by @ProDave is especially good if this can be fitted later...perhaps very much later.

And what number should I try to achieve? Or is this what I should ask the SAP assessor?

 

Is air change target the same as air pressure test results?

 

Do you mean advice about the PV? To be honest,  that's one modification I am quite accepting of. At the end of the day, it will only help to make the place more energy efficient and is least evasive.

[Conor]

If the assessor has assumed a worst case airtightness, and you get a much better result, you may well pass.

 

There are lots of people to blame for this, but none fully responsible. It's the embedded culture of "that'll do", "not my problem" and a system that is rigged by developers .

 

PV is a no-brainer regardless of the air test.

[eandg]

48 minutes ago, Conor said:

If the assessor has assumed a worst case airtightness, and you get a much better result, you may well pass.

 

There are lots of people to blame for this, but none fully responsible. It's the embedded culture of "that'll do", "not my problem" and a system that is rigged by developers .

 

PV is a no-brainer regardless of the air test.

I can't find any info on the impact of airtightness on SAP - our as designed SAP is 91B presuming an ACH of 2.5. I think we subsequently upspecced the insulation but would an improved ACH (say to 1-1.5) boost the SAP a few points into an A in any case?

[saveasteading]

1 hour ago, Maria said:

air change target the same as air pressure test results?

 

No.

The former is to give occupants fresh air to breathe, in a controlled manner. The latter is to avoid uncontrolled draughts, and so save energy.

[Dave Jones]

20 hours ago, nod said:

I’ll give you an example now 

The area you are looking at is down for 80 mill of insulation the 47 mil insulated plasterboard I’ve gone 80 mil insulation Superfoil another stud 80 mil insulation Then insulated PB 

The sap guy can only take my word that the whole house insulation has been up rated 

 

not any more.

 

new regs. every cold bridge, insulation detail etc has to be photographed with geo tag to prove its all been done.

[nod]

29 minutes ago, Dave Jones said:

 

not any more.

 

new regs. every cold bridge, insulation detail etc has to be photographed with geo tag to prove its all been done.in reality 

Tgere not

[Huckleberrys]

What sort of heating system do you have? Is there chance for an upgrade there to something more SAP friendly?

[Maria]

On 23/07/2023 at 12:02, nod said:

On 23/07/2023 at 11:32, Dave Jones said:

 

not any more.

 

new regs. every cold bridge, insulation detail etc has to be photographed with geo tag to prove its all been done.in reality 

Tgere not

Expand  

I think it's for the building regs submitted after 1st June 2022.

[Maria]

On 24/07/2023 at 06:47, Huckleberrys said:

What sort of heating system do you have? Is there chance for an upgrade there to something more SAP friendly?

Mains gas, combi boiler and thermostat rads

[saveasteading]

14 minutes ago, Maria said:

Mains gas, combi boiler and thermostat rads

I vaguely remember the inputs and tickboxes for boiler and controls make a big difference.