Wall firepeoofing quesion.

[ProDave]

I thought I had seen just about every form of house construction, but here is a new one for me.

Terraced ex LA house, been stripped bare for major refurb and rewire.

In the kitchen, the party wall between this and next door appears to be just a timber frame, with 3 layers of plasterboard on the frame (presumably the same next door on the other side of the frame)

Customer wants sockets on that wall. There were none before, in fact there are no electrics on the party walls at all.

I can't go cutting holes in the 3 layers of plasterboard without compromising the fire rating.

The only solution I can see is leave the 3 layers alone, batten it to make a service void and then a 4th layer of plasterboard. He will have to accept the room shrinking a little.

Anyone encountered this before?

 

[Sharpend]

You have to maintain the fire barrier, you will need to put the fire putty into the back box if you cut into the wall. 

https://www.firesealsdirect.co.uk/acoustic-intumescent-putty-pads.html?

 

[ProDave]

The problem as I see it is not just the back boxes. To get the cabes to the boxes I will need to cross the studs so that's more holes in the tripple plasterboard.

I just hope the customer agrees to the service void idea then I can leave the tripple plasterboard alone untouched.

 

[Sharpend]

The simple answer to that is cut out with holesaw, then keep the circles and repatch then back in with some plaster skim. 

 

[Murdoch]

I don't think you are allowed sockets in such a wall .....................but why I think that I can't remember.

On an estate near me, some of the homes are built with the "party wall" which has one layer of plasterboard each side ...........................I did a rewire in one a couple of years ago and refused to put any sockets in the "party" wall

 

[Sharpend]

Sockets are permitted, they are not allowed to be back to back, there must be a fire barrier maintained therefore the need to install the fire putty.

if it is a new build scenario then you’d put the fire putty behind the back box, the putty would need to extend approx an 1” past box to all sides. 

Alterantively you can put the fire putty inside the back box wrapped to cover all metal, I find this method a little messy though. 

Altenative options are available to the putty such as intumescent pads that expand on heat. These are stuck into the rear of back box. 

 

[Murdoch]

Sockets are permitted, they are not allowed to be back to back, there must be a fire barrier maintained therefore the need to install the fire putty.

if it is a new build scenario then you’d put the fire putty behind the back box, the putty would need to extend approx an 1” past box to all sides. 

Alterantively you can put the fire putty inside the back box wrapped to cover all metal, I find this method a little messy though. 

Altenative options are available to the putty such as intumescent pads that expand on heat. These are stuck into the rear of back box. 

Any chance you can add a link to such guidance ?

 

[ProDave]

My point is there are so many hoops to maintain the fire rating if you fit the sockets IN the fireproof wall. So I am suggesting leaving the fireproof wall alone, putting vertical battens on the wall following the studs to create a service void then an extra layer of plasterboard.

I will be suggesting this to the customer on Monday. It means the room will shrink by about 40mm

 

[Murdoch]

^^ sounds like a good old dose of common sense applied . 

Like it

 

[Geoff1946]

Could you offer surface wiring as an alternative, using a skirting system.?

 

[Adrian]

My point is there are so many hoops to maintain the fire rating if you fit the sockets IN the fireproof wall. So I am suggesting leaving the fireproof wall alone, putting vertical battens on the wall following the studs to create a service void then an extra layer of plasterboard.

I will be suggesting this to the customer on Monday. It means the room will shrink by about 40mm

I would go with that plan I  have done the same thing a few times. If it's the kitchen wall add nogging in to support the wall units 

 

[Sharpend]

Any chance you can add a link to such guidance ?

This is a detail of the requirement 

https://www.checkmate.uk.com/TechMan/rightcontent.asp?

http://www.british-gypsum.com/~/media/Files/British-Gypsum/WHITE-BOOK-Sector-Guides/WBHRMO/WBHRMO-3-Timber-Frame-Solutions-1501.pdf

I’ll look for a reg link later. 

 

[binky]

could you not just fill back void behind socket with fire rated expanding foam?

 

[Tony S]

This really is a question to put to the fire brigade. You’re well away from LFB so you should get a sensible answer.

My only dealings with fire proofing cable runs was in industrial runs. Luckily we had two retained firemen on site, they got the local station officer to come in and give advice. Fire proof walls are one thing, I got roped in to a job with blast proof walls. What a bloody headache!

 

[ProDave]

The customer has agreed to the stud and service void solution. That's both easier for me and avoids disturbing the fire rating of the wall.

This is only the second time I have encountered terraced houses without a brick or stone wall between them as a party wall (and the first one I only discovered when I knocked a hole through to next door, but that's an old story)

 

[Sharpend]

I'm all for an easier life Dave so well done- ever considered sales as a profession?