On Sun, 30 Dec 2007 15:12:50 -0800 (PST), a particular chimpanzee,
Richard randomly hit the keyboard and
produced:

Hi, I'm about to embark on boarding out my loft for light storage, and
felt that it would be a good time to also remedy the lack of fire
breaks in my mid terrace house. I cant seem to find any advice about
firebreak specifications or building regs so would be grateful if I
could be shown in the correct direction. I cannot decide whether to
build up the tops of the dividing walls (visible) with block and
mortar (if so is there a specific specification? I was thinking
fixing firfix to the dividing chimneys for e.g.) or with stud and
plasterboard (again what is the spec). I feel the latter would be
easier but the former may be more sturdy/soundproof. Any advice on
which to choose and how to go about it would be gratefully received.
How do you fix to the roof if the rafters dont line with the wall -
can you use noggins in wood? Many Thanks, Richard.

Are you doing this in conjunction with your neighbours? If not it's
at least best to warn them what you're doing. Strange knocking noises
directly above their bedroom ceilings may get you complaints via
Environmental Health and Building Control. It's also going to be a
lot easier and more effective if you can get to both sides of your new
party wall.

So long as you're not making the situation any worse in terms of
structure or fire safety than before, the work is not subject to
Building Regulations. The Party Wall Act may have a bearing on what
you're doing, but this is a civil matter between you and your
neighbour(s).

Masonry is obviously easier to do from one side, is more robust, and
will resist sound transmission better. Lay your blocks flat rather
than trying to lay two leaves, make sure that they are well mortared
to avoid air paths, and fill the space between the wall and the
felt/covering in Rockwool.

If you want a party wall in studwork that will form an effective sound
barrier, it needs to be done as two separate stud walls, each
independent of the other, lined with 2 layers of 12mm plasterboard on
each side. A single stud could be used, but it wouldn't form any
serious impediment to noise. It would also not help you very much if
there was a fire in your neighbours unless you could plasterboard
their side of the stud wall (if they have a fire, the timber on their
side is unprotected and would burn through, collapsing the stud wall).
As you say, you can noggin between the rafters, but fill the space
over the top with Rockwool.

If it's just life safety you're worried about, a third option could be
a 'cavity barrier' such as Rockwool Fire Blanket
(http://www.rockwool.co.uk/sw55784.asp).
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"

Many thanks for your helpful reply - heres the answers inline..

Are you doing this in conjunction with your neighbours?

Yes

Masonry is obviously easier to do from one side, is more robust, and
will resist sound transmission better. *Lay your blocks flat rather
than trying to lay two leaves, make sure that they are well mortared
to avoid air paths, and fill the space between the wall and the
felt/covering in Rockwool.

The party wall is likely 4in single skin brick (possibly 9in although
unlikely), so I'd be building ontop of this if that changes opinion. I
would therefore imagine blocking on edge as per usual, but with single
skin? Would you fix to the chimneys with wall ties to increase
strength?

Is there a more effective way to seal to the slopes of the roof than
rockwool - would you bother cutting angled blocks to fit the spaces,
or is this overkill?

If you want a party wall in studwork that will form an effective sound
barrier, it needs to be done as two separate stud walls, each
independent of the other, lined with 2 layers of 12mm plasterboard on
each side. *A single stud could be used, but it wouldn't form any
serious impediment to noise. *It would also not help you very much if
there was a fire in your neighbours unless you could plasterboard
their side of the stud wall (if they have a fire, the timber on their
side is unprotected and would burn through, collapsing the stud wall).
As you say, you can noggin between the rafters, but fill the space
over the top with Rockwool.

As someone else pointed out, I dont really need soundproofing come to
think of it - just the physical barrier for security and the
fireproofing, so I guess fireproof plasterboard on both sides of a
single skin stud would be effective. Would you bother installing
anything into the stud cavity??

What would your personal choice be in this situation - stud or block?
Which spec blocks would you use btw.

Are there any alternatives to heavy chipboard panels for the floor -
stronger but lighter would be the ideal (whilst still reasonably
priced of course!)

Many thanks for all your help..

Richard wrote:

As someone else pointed out, I dont really need soundproofing come to
think of it - just the physical barrier for security and the
fireproofing, so I guess fireproof plasterboard on both sides of a
single skin stud would be effective.

I wouldn't... you say security is a concern: if you consider that
there's a risk of a scrote breaking into your neighbour's house and
climbing up into his roofspace in order to enter your house, do you
think a couple of sheets of plasterboard will impede his progress for
more than a few seconds?!

Also, I don't know how big your loft hatch is but that might well be an
issue when it comes to taking sheets of plasterboard up there; at least
you're going to be restricted to using small bits only.

David

"Lobster" wrote in message
...
Richard wrote:

As someone else pointed out, I dont really need soundproofing come to
think of it - just the physical barrier for security and the
fireproofing, so I guess fireproof plasterboard on both sides of a
single skin stud would be effective.

I wouldn't... you say security is a concern: if you consider that there's
a risk of a scrote breaking into your neighbour's house and climbing up
into his roofspace in order to enter your house, do you think a couple of
sheets of plasterboard will impede his progress for more than a few
seconds?!

Yes.

Also, I don't know how big your loft hatch is but that might well be an
issue when it comes to taking sheets of plasterboard up there; at least
you're going to be restricted to using small bits only.

Good point. Probaly best to use blocks if they can be eaily taken up.

Doctor Drivel wrote:

"Lobster" wrote in message
...
Richard wrote:

As someone else pointed out, I dont really need soundproofing come to
think of it - just the physical barrier for security and the
fireproofing, so I guess fireproof plasterboard on both sides of a
single skin stud would be effective.

I wouldn't... you say security is a concern: if you consider that
there's a risk of a scrote breaking into your neighbour's house and
climbing up into his roofspace in order to enter your house, do you
think a couple of sheets of plasterboard will impede his progress for
more than a few seconds?!

Yes.

I remember enlisting the help of one of my sons with a renovation
project a few years ago, and set him on to demolishing a stud partition.
He was able to climb through it in a matter of minutes - mind you, he
was only 9 at the time.

David

"Lobster" wrote in message
...
Doctor Drivel wrote:

"Lobster" wrote in message
...
Richard wrote:

As someone else pointed out, I dont really need soundproofing come to
think of it - just the physical barrier for security and the
fireproofing, so I guess fireproof plasterboard on both sides of a
single skin stud would be effective.

I wouldn't... you say security is a concern: if you consider that
there's a risk of a scrote breaking into your neighbour's house and
climbing up into his roofspace in order to enter your house, do you
think a couple of sheets of plasterboard will impede his progress for
more than a few seconds?!

Yes.

I remember enlisting the help of one of my sons with a renovation project
a few years ago, and set him on to demolishing a stud partition. He was
able to climb through it in a matter of minutes - mind you, he was only 9
at the time.

To climb into a loft then through a stud wall and then down into the house
below you must have something worth getting. If it is that valuable then it
shouldn't be in the house.

I wouldn't... you say security is a concern: if you consider that
there's a risk of a scrote breaking into your neighbour's house and
climbing up into his roofspace in order to enter your house, do you
think a couple of sheets of plasterboard will impede his progress for
more than a few seconds?!

Really more a privacy than full on security issue then I guess.

Also, I don't know how big your loft hatch is but that might well be an
issue when it comes to taking sheets of plasterboard up there; at least
you're going to be restricted to using small bits only.

Hatch is about 2.5ft square so pretty big by all accounts I guess.
Thanks.