Hi, I want a small extension to accommodate a 2x1m bathroom (internal area) and a 1.5x1m service area. I'd like an external brickwork, in terms of appearance, to blend with the rest of the house (cavity wall from 1970).
What is the U-value requirement for the new external walls, please?
Am I looking at the right document below (doc L, vol 1: Dwellings, 2021 w/ 2023 amendments)?
www.gov.uk
On page 35, table 4.2 says the requirement is 0.18 W/(m2·K) U value, which would require 400mm-ish thick walls. Is my understanding correct?
Isn't it too much for an extra bathroom and service area?
It also says:
"If meeting such a standard would reduce the internal floor area of the room bounded by the wall by more than 5%, a lesser provision may be appropriate"
Ok, but what constitutes a lesser provision?
It doesn't point to any explanation. Can I consider as appropriate whatever U-value I want?
Is this what we pay tax for? For them to create difficult, unclear regulations? Gosh!!!
It's a side extension and I want to leave a foot passage to the backyard, therefore I'm trying to make the extension as narrow as it can be.
In the worst-case scenario, I think about accessing it via an external door, despite being an adjoining extension, just to be considered a non-habitable space and lessen the requirements, etc.. but only if necessary and if it makes sense.
I appreciate any help, please.
Thanks.
What is the U-value requirement for the new external walls, please?
Am I looking at the right document below (doc L, vol 1: Dwellings, 2021 w/ 2023 amendments)?
Conservation of fuel and power: Approved Document L
Building regulation in England setting standards for the energy performance of new and existing buildings.
On page 35, table 4.2 says the requirement is 0.18 W/(m2·K) U value, which would require 400mm-ish thick walls. Is my understanding correct?
Isn't it too much for an extra bathroom and service area?
It also says:
"If meeting such a standard would reduce the internal floor area of the room bounded by the wall by more than 5%, a lesser provision may be appropriate"
Ok, but what constitutes a lesser provision?
It doesn't point to any explanation. Can I consider as appropriate whatever U-value I want?
Is this what we pay tax for? For them to create difficult, unclear regulations? Gosh!!!
It's a side extension and I want to leave a foot passage to the backyard, therefore I'm trying to make the extension as narrow as it can be.
In the worst-case scenario, I think about accessing it via an external door, despite being an adjoining extension, just to be considered a non-habitable space and lessen the requirements, etc.. but only if necessary and if it makes sense.
I appreciate any help, please.
Thanks.
