Nigel Lewis
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spaceandstyle.bsky.social
Nigel Lewis
@spaceandstyle.bsky.social
Architectural designer and serial upcycler.

Find me at www.spaceandstyle.co.uk/
It makes no difference whether the insulation is applied to the inside of a building or the outside. When on the inside the only issue is possible cold bridging where internal walls or partitions meet the external walls. If your "efficiency" expert does not understand that he/she is not an expert.
August 27, 2025 at 1:31 PM
I am a bit rusty on this issue, but even in the diagram 5.3 It makes it clear that if the cavity is completely filled with insulation a cavity closer is not required at the top of the wall. As it states "Close cavity at top of wall (unless cavity is totally
filled with insulation)".
July 14, 2025 at 11:29 AM
Page 138 of the Merged ADs (page 54 Part B) states where cavity barriers are needed. Unless your builder has an integral garage or more than 2 storeys, he doesn't have Compartment walls.
assets.publishing.service.gov.uk/media/6717d2...
assets.publishing.service.gov.uk
July 14, 2025 at 9:00 AM
Other northern European countries manage to build & #retrofit houses to high standards. But here with an unskilled workforce barely reading plans or manufacturer's instructions, scam spray foam installers & the media running scare stories of heat pumps that don't work, it is an uphill struggle.
May 22, 2025 at 12:59 PM
The rafters sitting on the ceiling joists is very unusual. Usually the rafters sit on the same wall plate as the ceiling joists, or a pole plate above the the ceiling joists. Importantly, you will get a good level of insulation over the old wall even if reduced to 70mm near the external insulation.
May 21, 2025 at 9:09 AM
You actually have a much better situation than the majority of UK houses. By having the rafters cantilevered beyond the wall like that, you won't end up with the roof insulation being heavily reduced / squeezed at the eaves.

The airtightness of the ceiling meets the inner face of the wall.
May 20, 2025 at 8:43 PM
Because, it is a political issue.

Policy sets the direction of travel, regulations coerce builders, installers and manufacturers and incentives encourage home owners. Those things cannot happen without a political will.
May 9, 2025 at 2:15 PM
I like a lot of what you say, but sadly what a lot of people will take away from your article is that heat pumps are nonsense.

To me the crux of the issue is that UK homes are generally poorly insulated, that is what should be the full focus of Government policy.
May 9, 2025 at 10:36 AM