Regs for floor and roof insulation?

[d000hg]

I never said it was all about insulation, I'm not sure why you're harping on about that still. I said insulation was a major contributor to thermal efficiency, because it is. It's what the building control guy said was his biggest concern too when we described the project.

 

[d000hg]

Is the construction solid log lap? Thats what Im asking.

Its possible to get log lap cladding, then the construction can be timber frame, but look the same.

Yes, the walls are constructed of interlocking 70mm thick logs/planks.

 

[Notch7]

BTW, SAP is only for domestic properties

Thats correct.
My apologies to the OP for misleading.

If its classed as a new commercial building would a SBEM not apply?

In order to demonstrate compliance with Approved Document L2A you must provide your Building Control Officer with a SBEM calculation for each new commercial building

https://energy-test.co.uk/sbem-calculation/

 

[d000hg]

In a bit of a jump, what exactly is the point of regulations, to go to basics? The guy we talked to today from the council pretty much said (maybe he shouldn't) that they are really only relevant when it comes to selling a property, and that you don't have to have them signed off before you can use the building or anything.

Is that true, because I thought the council would come chasing us to check any new building was compliant and penalise us if it wasn't. Not that we don't want to meet regulations, but is that true?

 

[d000hg]

Thats correct.
My apologies to the OP for misleading.

If its classed as a new commercial building would a SBEM not apply?

In order to demonstrate compliance with Approved Document L2A you must provide your Building Control Officer with a SBEM calculation for each new commercial building

https://energy-test.co.uk/sbem-calculation/

Ah yes that was it. The BC guy mentioned this but said he has no preference how we classify it. He seemed quite helpful which is perhaps not what I had anticipated, I'd thought he'd be finding things to pick at.

It's within our curtilage, a structure we will build in our garden, but may then allow a company to operate out of. Does that make it a commercial or residential property (there are no bedrooms)? Or both? It could later be used for something else. That said, the guy said the overall process for regs is quite similar, with small details different.

He also said we do not HAVE to get SAP (for residential), that's just one option. The way he described it, these are something you can provide to help BC make their recommendations. He said we could also provide weighted average, elemental calculations, or anything else reasonable. It all seemed kind of subjective.

 

[Notch7]

Is that true, because I thought the council would come chasing us to check any new building was compliant and penalise us if it wasn't. Not that we don't want to meet regulations, but is that true?

nobody checks a construction gets a building regs certificate -it only gets picked up during a sale.
Some private building inspectors will threaten to cancel if the job drags on and they cant release the final cert -I don't know if the LA have a time limit

Generally where a project is built by a builder, the householder would chase the builder to get the final certificate -sometimes the project will have a final payment or a retention that wont be released until the final cert is released, so it puts pressure on the builder to make sure the job gets signed off.

strictly speaking buildings insurance would be invalid if the construction had no certificate.

 

[Notch7]

It all seemed kind of subjective.

Not really.

Building regulations dont dictate how something should be built, only that ultimately it should comply to the regulations.

There are various ways to calculate thermal efficiency, the most basic is just to specify each part, floor, walls, roof etc. But modern houses may not fit within those parameters, so other methods of calculating the overall efficency may be used -most common with orangeries which have more glass than the 25% rule.

 

[Leofric]

So this is basically the same sort of inputs I've done in my noddy spreadsheet - but then the actual calculations are much more involved, presumably using actual modelling of some sort (air flow, etc?) rather than just averaging the U values from each element? Is that form ALL someone would need to do the SAP test or just the starting point? I was surprised it doesn't ask how many windows and what size, for instance.
And, is the test entirely analytical and deterministic i.e. if I gave the exact same information to two people would I get the same answer, or is there some human subjectivity? Put another way when you pay someone £300 - which is not a lot of an architect's time, and I can see people charging MUCH less - are they poring over calculations or do they stick it in a computer and press a button, or is knowing how to get the information into the software correctly the skilled part in the same way that using CAD or Photoshop is? Looking at some of the prices I can see advertised, those guys cannot be doing much work at all - but maybe one SAP is NOT the same as another?

If you already have a SAP calculation/certificate, does that mean the building regs inspector will accept it for part L or does it only inform their decision?

Oh and - is the overall output of all this to determine your actual energy use, or your emissions, or your energy cost (like EPC)?

this could go on for some time .

 

[JP_]

have you tried using https://www.uvalue-calculator.co.uk/calculator/floors/ground floor/
this will give a U value for floor, wall, roof. If each is in line with regs, then that should be OK, I guess.
Personally, I'd always go above regs if it was something I was planning to live in for a long time. Insulation may be expensive today, but it won't be as expensive as gas / electric over the next 50 years...

 

[d000hg]

this could go on for some time .

You said to ask questions. Here are some specific questions for which I'm certain someone with your experience can very easily give answers.

 

[Leofric]

LOL - three pages and its still just about insulation it could go on a lot longer yet.

BTW, SAP is only for domestic properties

yes it is but I thought a possible future dwelling was now being discussed.As somebody has said SBEM for commercial,SAP for dwelling. That should put the cat among the pigeons

 

[d000hg]

have you tried using https://www.uvalue-calculator.co.uk/calculator/floors/ground floor/
this will give a U value for floor, wall, roof. If each is in line with regs, then that should be OK, I guess.
Personally, I'd always go above regs if it was something I was planning to live in for a long time. Insulation may be expensive today, but it won't be as expensive as gas / electric over the next 50 years...

And even then getting a definitive idea what the regs says on each line isn't something anyone here knows, or is at least willing to share.

I'll look but as I understand it, our walls definitely WON'T. So this whole thread started based on trying to figure out if I could adequately insulate the floor and roof to compensate since we don't want to clad our walls and lose their character. Hence the little spreadsheet to try and guess a building U value ballpark figure to be working from. The BC guy we chatted to reckoned each individual wall must have U<.7 for reasons of condensation which would suggest it's problematic, but even then he didn't say it was impossible. If he said said "you can't" that might be preferable in a way!

 

[Leofric]

You said to ask questions. Here are some specific questions for which I'm certain someone with your experience can very easily give answers.

I was joking,but you are starting to sound sarcastic .You ask too many questions,just get somebody to make a building regulations application for you. I have never heard such a load of waffle about a building regulations approval for a relatively small building.

 

[Leofric]

insulate the floor and roof

what is the proposed floor and roof construction , does anybody know don't think it will be a 'timber raft' unless it is floating on water

 

[Leofric]

Oh and - is the overall output of all this to determine your actual energy use, or your emissions, or your energy cost (like EPC)?

Have you read the SAP information? Thought you might have given in by now