Party Wall requirement

hi if you look at the homebond book it will give you all the relevant information.Its available in most bookshops and comes in very handy.

@nai wrote:

Hi folks,

Just a quick question about an extension my neighbour and I are thinking about :

We hope to build an extension sharing a common wall along the party line but are just unsure whether we have to build either

a. Build a 4″ cavity wall with two leafs and 4″ cavity filled with insulation with batten/insulation/slab outside or

b. Build a 9″ solid wall (4″ blocks on flat) and the insulate outside using battens/insulation/slabs

We are concerned with 1. Complying with Building regs in relation to Fire and 2. Sound insulation

Can anyone outline what the regulation/standard practice is and what the best method for insulation would be ?

Thanks,
nai

Homebond isn’t that hard to find. I bought a updated version less than a year ago. Keep looking, it will come in useful in the building of your extension.

But regards to your question. In terms of sound, The solid 215mm (9″) wall gives a better sound transmitance resistance. It is easy to think that a cavity wall would give better results bcause sound would find it difficult to travel across the gap. But this slight advantage is countered by the fact that the walls are separate they are less stiff and so less resistant than solid walls.
To get the same resistance in a cavity wall as a solid wall, a denser block must be used. With regards the insulation. In a cavity situation. Board type insulation would actually lower the resistance. A quilt type would help, but fixing is a problem.

As for fire, a one hour rating can be achieved easily with either type wall, as it will be plastered on both sides. And for reference, wet plaster direct to the wall gives better fire protection than standard slabs on battens.

http://www.buy4now.ie/eason/shopping.aspx?loc=C&catid=A_NHBGS

you can buy it at buy 4 now.ie in the easons bookshop for 45euro
its a bible!