First decent article I’ve read on why new builds are cold ...

[Bitpipe]

Highlights poor airtightness, dot and dab plastering  and bodged tests - all issues we’ve been highlighting here for ever.

 

https://www.theguardian.com/money/2019/feb/02/new-build-homes-why-some-owners-are-left-feeling-the-cold

 

 

[joe90]

Very interesting particularly:-

 

that most of the houses built before 1900 were more airtight than expected, and in some cases better than required by the 2006 building regulations,

[ProDave]

I bought a new house in 1986, moving into that from the 1930's familly home, expecting it to be warm.  It was anything but.  I now know the dot and dab plasterboard was probably the main reason why.

 

Up here you will find a building technique that's like "dot and dab on steroids"  Old stone cottages (croft houses) are rarely left as bare stone. They are almost always lined with a thin timber frame (often just 2 by 2) and boarded over. Originally this would have been lath and plaster, now more commonly you find plasterboard.  But it is rare to find any insulation behind this. Instead you have a large irregular sized gap open to the loft space.  As an electrician, if I have to remove a switch or a socket, I can almost guarantee I will be met with an icy howling gale coming out of the hole.

[Declan52]

So the moral of the story is wet plaster on block work.  Can't hide anything like happens with dot and dab where you rely on the plasterer doing it right and if he hasn't then you don't know as it's hidden. 

Any one relying on a few tubes of caulk around their skirting to keep the draughts out really have been badly informed. 

 

[PeterW]

The new gun foam system instead of dot and dab is very good as it removes the air gap behind the boards too. A bead at the top also seals the boards on and stops draughts. It also gives a more solid feel as the boards are tight against the blockwork but does need clean walls with no snots. 

[Jeremy Harris]

Nice to see Paul Buckingham getting some well-deserved attention at last.  I've posted links to his papers on this before, but they are well-worth a read: https://www.aecb.net/still-taking-disgraceful-approach-build-quality-waving-goodbye-energy-savings/

[Declan52]

I think if I had bought one of them houses I would now be a resident of maghaberry prison.  It doesn't really take much of an effort to seal a house up or put insulation in and put it in right.  

[TerryE]

What I find interesting about the FIR images in the Guardian article is that -- to me at least -- they underline the whole issue of where the air tightness is achieved if at all: you can have a airtight(ish) living space but if there is free convective circulation within the dot-and-dab (or service) voids interchanging with external air, then this can act as an active heat pump dumping heat out of the house.  The airtightness should be achieved and verified before boarding out.

[Mr Punter]

Good point @TerryE but how would this work in a cold loft house, where it seems like the top floor ceiling plasterboard is the airtight layer?

[scottishjohn]

43 minutes ago, TerryE said:

What I find interesting about the FIR images in the Guardian article is that -- to me at least -- they underline the whole issue of where the air tightness is achieved if at all: you can have a airtight(ish) living space but if there is free convective circulation within the dot-and-dab (or service) voids interchanging with external air, then this can act as an active heat pump dumping heat out of the house.  The airtightness should be achieved and verified before boarding out.

totally agreed.

dry lining is a finish system not part of the shell of the house .

and that is what must be air tight .--the outer shell.

can anybody see them altering the regs to make air testing before drylining ,as obvious as it is that that is when it should be done.

when will that will happen? 

NEVER 

[ProDave]

48 minutes ago, TerryE said:

  The airtightness should be achieved and verified before boarding out.

Of course it is on a well built house with an air tight membrane then  a service void, as many of us have built.

 

It is this simple, and not expensive step that the main stream builders choose not to implement.