From Newsgroup: uk.d-i-y
On 06/08/2026 09:50, Tricky Dicky wrote:
RJH <patchmoney@gmx.com> wrote:
On 5 Aug 2026 at 14:44:39 BST, Tricky Dicky wrote:
Just over two weeks in the new bungalow and starting to find all the bodge >>> jobs. TodayrCOs issue is back boxes, the bungalow has two bedrooms in the >>> loft with four double sockets between them mounted in the dwarf walls which >>> are of unusual construction in that it is the first time I have seen this. >>> What I thought was PB turns out to be 25mm thick PIR boards lined both
sides with paper rather than foil with the facing side skimmed with
plaster.
https://www.dropbox.com/sc/9qljl6sg8o7fqjd/AABBtsjoIbllmpjrs9TTTlVva
Now for the bodge! Went to disconnect a small strip light dangling from its >>> wire just above a socket. I removed the socket to find an undersized hole >>> cut in the PIR, on the left an extra long screw was driven through the PIR >>> with the dry lining box on the back its lugs removed and the screw driven >>> through the back of the box. On the right the screw completely missed the >>> box and simply held the front on by the PIR. Another socket looks like it >>> is held on loosely in a similar way and I suspect all four are the same. >>> SodrCOs Law of course the light was not wired into the socket which only has
one cable coming into it so somewhere in the void is a junction box.
https://www.dropbox.com/scl/fi/s53jyum346cyj1sd9ues8/2026-08-05-13.02.34.jpg?rlkey=7ln7lrf3kzn6byrwqe65520y7&st=92dvuohn&dl=0
Now for the fix. I just need a quick and dirty way to get the sockets
safely back into use for now, long term I want to increase the number of >>> sockets and restoring the ring main in the process. For now I plan to open >>> out the holes and insert Tower 47mm dry line boxes which according to SF >>> will fit board thicknesses up to 42mm can anyone confirm this before I
order them?
IIUC you're trying to fix a socket/backbox to 25mm PIR.
I wouldn't bother - the quick fit types need decent support at the sides. The
backbox supported need support at the back.
Using PIR in this way is asking for trouble - fire/sound/fixing pixtures etc.
- just thumping it might crack the skim. What were the builders thinking - >> wouldn't have taken long to use PB when they were putting the partition in. >> And is the PIR on an external wall? If not it's pretty pointless anyway.
As a temporary safe fix I'd screw surface mounted boxes/sockets and fix at a >> noggin/stud. In the possibly misplaced hope there's a conveniently sited stud.
Or you could try fixing some ply at the back of the PIR (as per John's post) >> and hope it stays fixed - maybe partially screw the backbox to the ply before
threading it through the hole, then screw it tight once in. Then let the glue
go off. Then fix th socket.
Longer term I'd face the PIR with plasterboard. Or you might as well take the
PIR out if it's only on interior walls and reclaim the interior space.
Then use drylining boxes, or proper backboxes fixed to studs/noggins and/or >> new supporting timber.
Rob the bungalow was built in 1991 so PIR was around but I do not recall
ever seeing the sort of insulated PB around you see today, still as you say they could have insulated between the studs and overboarded with PB.
Although I have never seen this type of insulation before skimmed with plaster, I have seen exterior walls of PIR rendered the last one being an extension on a school and I always wondered how that would fare over time.
My eldest daughter bought a new build semi about 10 years ago and the party wall in the loft terminates just above ceiling level in the loft and the remainder is divided off with PIR.
The long term plan for the sockets in the upper bedrooms is to insert
noggins between the studs and attach metal back boxes to them if required I may overboard with PB and skim with plaster as well as take the opportunity to insulate the dwarf walls between the studs. For now I just need to get
the sockets functioning, I have 47mm dry line boxes arriving today and see how I fare with them @ -u1.49 each it is worth a punt to get things working until I have time to work on a more permanent solution.
The voids behind provide quite considerable long term storage space one is already floored and the plan is to do the same for the rest. At the maximum height the space is over 1200mm high so a very comfortable crawl space even for my old bones but I would not want to include the space into a room so
the walls will remain but likely improved and maybe additional openings provided to avoid having to crawl the full length to get to things.
It looks the wrong colour for PIR. Are you sure it isn't some sort of compressed fibre material ?. Office buildings have de-mountable
partitions made of similar stuff.
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