Party wall cavity?

[Geo]

Hope this is not too stupid a question - Is a party wall (1969 brick semi-detached house) single brick or cavity?

Geo

[Phil L]

It could be either or neither, it could be double skin but no cavity, there are no rules and all anyone in here can do is guess.

You can measure the brick panel outside, inbetween yours and next doors downstairs windows or doors (the bit that spans the party wall) then knock off the amount that belongs to you, plus the same amount that undoubtedly belongs to them, and what you are left with is the thickness of the party wall.

[Tony Bryer]

Could be either. If you look in the loft the brick bond should give you a very strong clue - all stretchers = cavity

[Weatherlawyer]

Can both parties agree to a test drilling into the brick? It should be fairly soft "common" brick. Or if you have a region you can clean the plaster off, the presence of "headers" will tell you it is a double brick solid wall.

In those days regulations were considerably more lax than modern dwellings are. A 5.5 mm masonry drill shouldn't do much damage. Though you might have to use a 7mm to get the depth.

Once you are in 4 inches you will know. If it is still drilling solid at 5" you have a single skinned double brick/ 9 inch wall.

[<me9]

Or single brick, My last house (of similar vintage) was. Soundproofing was one of the main reasons we moved.

[dg]

A semi from the 60's is most likely to have a cavity party wall. The party wall would normally be the same type as the external walls if these are traditional contruction

You can't rely on looking in the loft, as it was common to change from cavity to 9" or even 4 1/2" in the roofspace for simplicity and speed.

You could do a basic check by deducting the internal width from the external width, and deducting the external wall thicknesses, and if you have about 280mm you have a cavity and if you have less than 250mm its a solid wall. This assumes the party wall is not dry-lined.

dg

[Geo]

Looks like 4 1/2" in the loft. I had found this first but did not mention it in my original posting to avoid confusion.

Plaster on brick.

54" from windowsill end to next door's (windowsill end). 20" from approx same point internally to plaster so looks like about 13"-14" for the wall. Reason for asking was that we can hear nextdoors 13A plug being inserted - I supposes there could be a wall tie nearby conducting the sound.

At least all my rawlplugs wont be fighting with theirs'.

Thanks to all who replied for the suggestions.

Geo

[adder1969]

Isn't a wall that is as thick as a brick is long a "single brick" wall and one that is as thick as the brick is wide a "half brick" wall??