25% rule

[bennettp23]

Hi,

I'm having to deal with the 25% glazing rule. My limit is 11.5m2 but I'm at 19m2...

I'm looking at the level of insulation in walls, floor and vaulted roof. We also have existing solar panels and solar water heating - do they help at all or don't they matter as they are existing?

Other things I'm considering is composite plasterboard (but looks very expensive?) and increasing existing loft insulation.

Any tips gratefully received.

Thanks,

Paul.

 

[Notch7]

Hi,

I'm having to deal with the 25% glazing rule. My limit is 11.5m2 but I'm at 19m2...

I'm looking at the level of insulation in walls, floor and vaulted roof. We also have existing solar panels and solar water heating - do they help at all or don't they matter as they are existing?

Other things I'm considering is composite plasterboard (but looks very expensive?) and increasing existing loft insulation.

Any tips gratefully received.

Thanks,

Paul.

Get a specialist to do a SAPS test for you.

There are a few tricks:

1. include any energy efficiency improvements you have done in say last 3 years as part of this project.

2. I am surprised all the lights in your house are old fashioned light bulbs and 50watt halogens in the kitchen....I suggest you replace them with LED

3. Don't forget, if the extension will mean the loss of a window or door - that is a poor thermal element that will count as part of the existing.

I used to use energy-test.co.uk they always got my stuff to pass

 

[tony1851]

Hi,

I'm having to deal with the 25% glazing rule. My limit is 11.5m2 but I'm at 19m2...

I'm looking at the level of insulation in walls, floor and vaulted roof. We also have existing solar panels and solar water heating - do they help at all or don't they matter as they are existing?

Other things I'm considering is composite plasterboard (but looks very expensive?) and increasing existing loft insulation.

Any tips gratefully received.

Thanks,

Paul.

As above, have you added the area of any doors or windows covered over or no longer existing because of the extension?

 

[bennettp23]

As above, have you added the area of any doors or windows covered over or no longer existing because of the extension?

Yes done that.

 

[tony1851]

If you need to add extra insulation, adding more in the roof is the most cost effective, though even there the law of diminishing returns kicks in.
As Notch suggested, get an assessor to do a SAP. If you insist that you must have a pass, they will fix the figures to 'prove' it to Building Control; no one in Building Control checks them.
TPTB who enact these ridiculous paper exercises (because that's all they are) don't live on Planet Earth.

 

[bennettp23]

If you need to add extra insulation, adding more in the roof is the most cost effective, though even there the law of diminishing returns kicks in.
As Notch suggested, get an assessor to do a SAP. If you insist that you must have a pass, they will fix the figures to 'prove' it to Building Control; no one in Building Control checks them.
TPTB who enact these ridiculous paper exercises (because that's all they are) don't live on Planet Earth.

Agreed