Wall Chase Maximum Depth

Joined
26 Aug 2016
Messages
6,581
Reaction score
927
Country
United Kingdom
Our cinder block 2 inch walls fall apart as soon as you get a drill or chisel anywhere near. A scutch chisel seemed to be the best way. But I dug out loads of 35mm sockets and nothing collapsed yet! So common sense as well as regs apply!
 
Last edited:
Joined
26 Aug 2016
Messages
6,581
Reaction score
927
Country
United Kingdom
oh yeah sorry Steve auto correct strikes again!! Can I employ you as my auto correct in future ;)
 
Joined
8 Sep 2011
Messages
4,637
Reaction score
590
Location
Warwickshire
Country
United Kingdom
As John has suggested, I think some boxing might be the way to go, the cheapest no mess solution really. Just need to build it and make good.

There are more destructive ways of doing it, that would involve re-doing the entire wall, but that seems a bit out of the realms of practicality.
 
Joined
29 Aug 2013
Messages
60
Reaction score
5
Location
Cheshire
Country
United Kingdom
Hi Folks, thanks for all your brilliant replies.
I've decided to chase only 12mm out of the brick and put the wires in oval conduit rather than round.
I've been reading up on these 'lounge plates' for sat\TV\FM and it seems they only need 2 lengths of coax not the 4 thought was needed and was puzzeling about how to fit in the wall. So no need for the 25mm round.

With only 2 I can fit 2 coax and a network cable to the plate, and the chase will only be 12mm thick to get it below the surface of the brick.

I've done a trial cut and used a (borrowed) chaser which seemed the least destructive given the fragility of the brick.
Top tip with the scutch chisel in the back of the chase, works a treat with very little force needed to nibble away the strip isolated by the chaser.

I've decided to scrap one of the accessories and fit everything into one 2 gang backbox, so that I don't have to worry about the long horizontal 'chase' at the bottom of the wall.

I'll try and post some photos later.
 
Joined
29 Aug 2013
Messages
60
Reaction score
5
Location
Cheshire
Country
United Kingdom
I experimented a bit and it seems it is much easier to re-thread through 25mm oval conduit than 20mm round anyway, and almost half the chase required, only about 12mm to completely recess the oval in the block(to ease any future order from on high to replaster).

The 35mm back boxes are in the block 25mm, and I managed to do this carefully without smashing the back of the block out. I've a feeling that the metal backbox is as strong as the brick I've removed, but I've left a big gap between the AV wall plate and the next back box to ensure that I haven't compromised the inner wall.

I'm just deciding now weather to fill the small gaps behind and around the wall plate with cement for strength or plaster board adhesive. Both seem pretty strong though.

I managed to use three vacuum cleaners to catch the dust from the chaser, one connected to the chaser and the other two held wither side by some reluctant volunteers! This kept the dust to a minimum, although dust sheets were still needed over everything.

Anther tip was using a 2kg SDS with a scutch chisel. My only experience before was with a 5kg SDS and my feeling was that this would destroy the wall, but with the 2kg and scutch I could finish off the chase and backbox detail without much effort, lighter too!

The wall chase chisel for the SDS didn't seem much help and had a tendency to dive in. Without the grooves already cut by the wall chaser, the chase chisel would have also been really difficult to use, as the profile is curved and the inside corners of the chase would still have needed lots of work. Maybe the more expensive square section chisel would have been better, but in the brittle block, the scutch would work easily as well for both the sides and the back.

Thanks again for all your help. I'll post a photo or two when I find my camera in all masonry dust!
 
Joined
11 Jan 2004
Messages
38,380
Reaction score
1,789
Country
United Kingdom
Excuse me for butting in....

I am going to install 2x BG 8EM8 boxes in the bedroom.

They are 50mm deep.

They are going in a cavity wall with brick on the side where the boxes are being recessed.

This will exceed the maximum depth, no?
 
Joined
26 Aug 2016
Messages
6,581
Reaction score
927
Country
United Kingdom
Depends if you class that as a chase. If so, you can remove a whole brick without a lintel, so you're fine if the width is less than a brick. Even if it were a chase, you might have thick enough plaster anyway if you're lucky!
Put them above each other if you're really worried.
 
Sponsored Links
Top