Party wall construction not done with brick or concrete

Kace2022 · 4 May 2022 at 6:13PM

Hey folks,

We're looking at an end of terrace plot (new build) and discovered during conveyancing that the party wall shared between the house and neighbour is not separated by brick or concrete block. This is essentially the wall between our living room and theirs. Not entirely sure this is standard and we should worry about a fire breaking out next door that blitzes our house?

The material is 2x layers 12.5mm soundblock board to insulated timber frame with 9mm sheathing board, fully insulated cavity, insulated timber frame with 9mm sheathing board , faced with 2 x 12.5mm soundblock.

Cheers

andy444 · 4 May 2022 at 7:51PM

This is fairly standard. Although timber frame construction isn't widespread in this country (unlike Scandinavia and America), it is gaining popularity here and there's nothing particularly unusual in that wall composition.

You could argue that one layer of FireLine plasterboard could be placed either side of the wall to fully prevent the spread of fire but the wall as it's currently designed will probably prevent a fire entering into the next house for over an hour which should be enough time for a fire engine to arrive.

Ramouth · 4 May 2022 at 8:01PM

2 layers of 12.5mm sound block on a twin frame should give you around 90 min fire resistance. Assuming the house is fairly modern as it is timber framed, then the party wall construction will have been approved by building control so it’s not something to worry about.

Kace2022 · 4 May 2022 at 9:22PM

The Mrs is naturally very worried that there's no block cement in between us and the neighbour. Block cement would provide a much longer duration of fire resistance I'd presume?

user1977 · 4 May 2022 at 9:47PM

How long does she think she needs?

ProDave · 4 May 2022 at 9:50PM

Seen houses like that up here, except it was 3 layers of plasterboard each side and another feature was no penetrations in those plasterboard layers so no sockets on that party wall. I guess if they do put sockets or switches there they would need to be in metal fire rated back boxes with the itumescent pad in the back.

andy444 · 4 May 2022 at 9:54PM

There will be little significant difference. Your main concern should be about sound transmission through a timber frame wall rather than about fire. As stated above, it's a standard party wall construction technique nowadays.