Improving U value of house walls and Part L

wavetrain · 12 Apr 2009

I am considering adding internal insualtion to a house with 9" solid brick outer walls on a room by room basis as I decorate. But on some parts of the house eg the outside wall where the stairs run, I would have to compromise at 25mm (extratherm etc), otherwise the stairs would become too narrow to use.

Does part L require any improvement to insualtion of a wall to comply with current requirements for new build?

jeds · 12 Apr 2009

There is no regulation requiring you to upgrade existing walls. The sensible approach is to add as much insulation as reasonably practical -and economical.

If it's new build then you must comply with Part L and that means insulation must be fully designed to satisfy SAP 2005.

noseall · 12 Apr 2009

EXTERNAL WALLS:

"Where 25% or more of an external wall is re-rendered, re-clad or re-plastered or re-lined internally or where 25% or more of the external leaf of a wall is re-built then regulations would normally apply."

wavetrain · 12 Apr 2009

noseall said:
EXTERNAL WALLS:

"Where 25% or more of an external wall is re-rendered, re-clad or re-plastered or re-lined internally or where 25% or more of the external leaf of a wall is re-built then regulations would normally apply."

Does this mean if all of the outside of the house it stripped of render (roughcast) and then freshly rendered the U value of the walls would then need to meet current regs?

noseall · 12 Apr 2009

wavetrain said:
noseall said:

EXTERNAL WALLS:

"Where 25% or more of an external wall is re-rendered, re-clad or re-plastered or re-lined internally or where 25% or more of the external leaf of a wall is re-built then regulations would normally apply."

Click to expand...

Does this mean if all of the outside of the house it stripped of render (roughcast) and then freshly rendered the U value of the walls would then need to meet current regs?

Yes.

chappers · 12 Apr 2009

I thought BC were only concerned if you stripped the inner face of the wall.
However in your situation I know you want to improve the insulation in your home, but as BC need be none the wiser, just do what is practicable.

This came straight from the horses mouth, here in Oxford, with regards to a re-roof. "we are not bothered and wouldn't enforce, unless the job was part of a project we were involved in"

noseall · 12 Apr 2009

I thought BC were only concerned if you stripped the inner face of the wall.

I received a letter only on Thursday from b.c. specifying or detailing controlled work regards "External walls roofs and floors" . Even ceilings are involved. ffs

This came straight from the horses mouth, here in Oxford, with regards to a re-roof. "we are not bothered and wouldn't enforce, unless the job was part of a project we were involved in"

Common sense prevails, but they do get involved believe me.

Shytalkz · 12 Apr 2009

This came straight from the horses mouth, here in Oxford, with regards to a re-roof. "we are not bothered and wouldn't enforce, unless the job was part of a project we were involved in"

Obviously not bcsurveyor's patch then

^woody^ · 12 Apr 2009

There is a big debate on at the moment within building control circles regarding Part L, and the different opinions and interpretations and lack of enthusiasm for enforcing this particular part of the regs.

It is so onerous, but so understated that it is often ignored. And if the BCO's were to actively enforce Part L then their work load would increase uncomfortably.

If you consider that most BCO's are not even bothered with unauthorised extensions, alterations or structural issues, then what are the chances of them being interested when someone chops off 26% of their render?

wavetrain · 12 Apr 2009

Energy Performance Certificate

An Energy Performance Certificate is part of a Home Information Pack.The certificates are commissioned by the seller of the property (or their agent) from an accredited Energy Assessor, who visits the property to collect the relevant data and creates the certificate.

This data includes the date, construction and location of the house and relevant fittings (heating systems, insulation or double glazing, for example).

Assuming the above is correct, it would make a property more valuable if full account was made of the improvements to insulation that had been made by myself over a period.

How is the accredited energy assessor to to know what the U value of various improved walls are unless they were to take my word over the insulation I had fitted, and that those dg units really are argon filled with a soft coat low-e inner pane?

noseall · 12 Apr 2009

wavetrain";p="1194085 said:
How is the accredited energy assessor to to know what the U value of various improved walls are unless they were to take my word over the insulation I had fitted, and that those dg units really are argon filled with a soft coat low-e inner pane?

Click to expand...

Precisely.

You would be encouraged insulate your own home for selfish reasons and not particularly to satisfy reg's.

But, the government that would like to see all homes energy efficient for reasons that will be relevant long after we are gone. In other words it is in everyone's interest to spend money making homes more efficient now, so people can benefit for the entire lifespan of the building and not necessarily the lifetime of the occupant.

For those of you who are not contributing to the longevity of your genes i.e. having kids, then say stuff it to reg's.

wavetrain · 12 Apr 2009

Sorry Noseall, but I in fact do not knows all, and I do not know the answer to my question.

Is there any way that the improvement made to the insulation of the house be recognised at time of sale?

noseall · 12 Apr 2009

wavetrain said:
Is there any way that the improvement made to the insulation of the house be recognised at time of sale?

Yes, get it signed off by building control.

wavetrain · 12 Apr 2009

noseall said:
wavetrain said:

Is there any way that the improvement made to the insulation of the house be recognised at time of sale?

Click to expand...

Yes, get it signed off by building control.

But then are'nt we going to be back to the problem of BC requiring any renovation work to make an improved wall meet the current regs and as I explained before, if I insualte the wall with more than 25mm celotex which is next to the stairs, then the stair width would be too narrow...

chessspy · 12 Apr 2009

Hi, All, (and my old friend nose(all))
I've been retired from the biz for a few years now, and I don't want to get involved in the building regs/recognition of this discussion, but it seems to me that a few years ago there was a 'thinsulate' sheet that came out that looked like quilted bacofoil and was about 1/4" thick and was supposed to give the insulsation value of 2" of regular stuff.
My personal view is that wallpapering horizontally with expanded polystyrene lining 'paper' and blown vinyl over will do the trick.
And don't forget under the floors, (ground floor obviously), 4" of fluff inbetween the joists (supported on garden twine stapled to the underside of the joists at 12" distances) will do more good than most things. In most old houses, there is only 20mm of timber between you and the outside world, (temperaturewise) Doesn't matter in the summer ofcourse, but oh boy see your heating bills shrink in the winter.
I heat my house with a candle.

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Improving U value of house walls and Part L

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