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Loft firewall construction
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Dave N
Oct 21, 2011, 5:42:12 AM10/21/11
to
Finished my house renovation in August and fortunately have (fingers
crossed) managed to get a quick sale. Readers with long memories may
remember my efforts at replacing the staircase - see
http://groups.google.com/group/uk.d-i-y/browse_thread/thread/76a2dda864730efd
Anyway, the buyer's survey report's come back - I understand the
surveyor was generally happy but with one exception - the house is a
Victorian mid-terrace and there is no party firewall in the loft on
one side (a pretty common observation since in most areas building
regs didn't insist on one at the time of construction). The bank has
put a retention on the mortgage offer that is way out of proportion
with the cost of the work, so I guess they really want me to do
something about it! The existing party wall is 4.5" single thickness
up to first floor ceiling height.
Obvious solutions are to build a breeze block wall (about 10 sq m of
blocks plus aggregates, so about £150 + labour) or a timber stud wall
with fire retardant plasterboard cladding (materials would be about
£150 too). Have talked to our local building control folks who advise
that either method would conform to current regs if properly done,
with the caveats that the gaps at the top of a block wall should be
filled with foam and I need to check whether the plasterboard needs
skimming to achieve its specified fire rating (as far as I can see
from the British Gypsum White Book it doesn't if the cladding is on
both sides).
Anyway, to conclude the essay...what experience do contributors have
of building a firewall? Which method did you use and how easy/
difficult was it? And, finally, did you need to use the Party Wall
etc. Act notice? Next door is rented and the landlord may take some
time to trace, hence my interest in this.
crossed) managed to get a quick sale. Readers with long memories may
remember my efforts at replacing the staircase - see
http://groups.google.com/group/uk.d-i-y/browse_thread/thread/76a2dda864730efd
Anyway, the buyer's survey report's come back - I understand the
surveyor was generally happy but with one exception - the house is a
Victorian mid-terrace and there is no party firewall in the loft on
one side (a pretty common observation since in most areas building
regs didn't insist on one at the time of construction). The bank has
put a retention on the mortgage offer that is way out of proportion
with the cost of the work, so I guess they really want me to do
something about it! The existing party wall is 4.5" single thickness
up to first floor ceiling height.
Obvious solutions are to build a breeze block wall (about 10 sq m of
blocks plus aggregates, so about £150 + labour) or a timber stud wall
with fire retardant plasterboard cladding (materials would be about
£150 too). Have talked to our local building control folks who advise
that either method would conform to current regs if properly done,
with the caveats that the gaps at the top of a block wall should be
filled with foam and I need to check whether the plasterboard needs
skimming to achieve its specified fire rating (as far as I can see
from the British Gypsum White Book it doesn't if the cladding is on
both sides).
Anyway, to conclude the essay...what experience do contributors have
of building a firewall? Which method did you use and how easy/
difficult was it? And, finally, did you need to use the Party Wall
etc. Act notice? Next door is rented and the landlord may take some
time to trace, hence my interest in this.
NT
Oct 21, 2011, 6:47:43 AM10/21/11
to
On Oct 21, 10:42 am, Dave N <dneale...@yahoo.co.uk> wrote:
> Finished my house renovation in August and fortunately have (fingers
> crossed) managed to get a quick sale. Readers with long memories may
> remember my efforts at replacing the staircase - seehttp://groups.google.com/group/uk.d-i-y/browse_thread/thread/76a2dda8...
> Finished my house renovation in August and fortunately have (fingers
> crossed) managed to get a quick sale. Readers with long memories may
>
> Anyway, the buyer's survey report's come back - I understand the
> surveyor was generally happy but with one exception - the house is a
> Victorian mid-terrace and there is no party firewall in the loft on
> one side (a pretty common observation since in most areas building
> regs didn't insist on one at the time of construction). The bank has
> put a retention on the mortgage offer that is way out of proportion
> with the cost of the work, so I guess they really want me to do
> something about it! The existing party wall is 4.5" single thickness
> up to first floor ceiling height.
>
> Obvious solutions are to build a breeze block wall (about 10 sq m of
> blocks plus aggregates, so about £150 + labour) or a timber stud wall
> with fire retardant plasterboard cladding (materials would be about
> £150 too). Have talked to our local building control folks who advise
> that either method would conform to current regs if properly done,
> with the caveats that the gaps at the top of a block wall should be
> filled with foam and I need to check whether the plasterboard needs
> skimming to achieve its specified fire rating (as far as I can see
> from the British Gypsum White Book it doesn't if the cladding is on
> both sides).
>
> Anyway, to conclude the essay...what experience do contributors have
> of building a firewall? Which method did you use and how easy/
> difficult was it? And, finally, did you need to use the Party Wall
> etc. Act notice? Next door is rented and the landlord may take some
> time to trace, hence my interest in this.
IIRC you can build it without permission as long as its on your side.
> Anyway, the buyer's survey report's come back - I understand the
> surveyor was generally happy but with one exception - the house is a
> Victorian mid-terrace and there is no party firewall in the loft on
> one side (a pretty common observation since in most areas building
> regs didn't insist on one at the time of construction). The bank has
> put a retention on the mortgage offer that is way out of proportion
> with the cost of the work, so I guess they really want me to do
> something about it! The existing party wall is 4.5" single thickness
> up to first floor ceiling height.
>
> Obvious solutions are to build a breeze block wall (about 10 sq m of
> blocks plus aggregates, so about £150 + labour) or a timber stud wall
> with fire retardant plasterboard cladding (materials would be about
> £150 too). Have talked to our local building control folks who advise
> that either method would conform to current regs if properly done,
> with the caveats that the gaps at the top of a block wall should be
> filled with foam and I need to check whether the plasterboard needs
> skimming to achieve its specified fire rating (as far as I can see
> from the British Gypsum White Book it doesn't if the cladding is on
> both sides).
>
> Anyway, to conclude the essay...what experience do contributors have
> of building a firewall? Which method did you use and how easy/
> difficult was it? And, finally, did you need to use the Party Wall
> etc. Act notice? Next door is rented and the landlord may take some
> time to trace, hence my interest in this.
Lightweight block is going to be far easier as you dont need next door
access to clad.
NT
NT
Oct 21, 2011, 7:31:10 AM10/21/11
to
Would it be possible to screw a few little blocks of wood to the last
bit of neighbour's side PB, and pull it into position after putting
glue on the frame? If by some miracle its doable, then it would be a
good bit quicker than a block wall. One layer of PB doesnt give a lot
of fire resistance time though.
NT
Andrew Gabriel
Oct 21, 2011, 7:49:03 AM10/21/11
to
In article <4cbc234a-6a12-46fa...@11g2000yqu.googlegroups.com>,
Another option might be to build the timber frame out of position,
fix the board to the neighbour's side, move and fix partition into
position, and then fix board to your side.
One thought - I would make sure the plasterboard doesn't contact
the sarking, as it may end up wicking water through. If the party
wall doesn't line up with a rafter (mine doesn't), then you probably
want something waterproof along the top of the partition to prevent
the plasterboard touching the sarking.
Getting sheets of plasterboard into the loft without breaking into
small pieces might be a challenge in some cases.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
NT <meow...@care2.com> writes:
> I've never tried this, and probably wouldnt, just a crazy thought...
> Would it be possible to screw a few little blocks of wood to the last
> bit of neighbour's side PB, and pull it into position after putting
> glue on the frame? If by some miracle its doable, then it would be a
> good bit quicker than a block wall. One layer of PB doesnt give a lot
> of fire resistance time though.
Would need to be a glue that didn't let-go in a fire.
> I've never tried this, and probably wouldnt, just a crazy thought...
> Would it be possible to screw a few little blocks of wood to the last
> bit of neighbour's side PB, and pull it into position after putting
> glue on the frame? If by some miracle its doable, then it would be a
> good bit quicker than a block wall. One layer of PB doesnt give a lot
> of fire resistance time though.
Another option might be to build the timber frame out of position,
fix the board to the neighbour's side, move and fix partition into
position, and then fix board to your side.
One thought - I would make sure the plasterboard doesn't contact
the sarking, as it may end up wicking water through. If the party
wall doesn't line up with a rafter (mine doesn't), then you probably
want something waterproof along the top of the partition to prevent
the plasterboard touching the sarking.
Getting sheets of plasterboard into the loft without breaking into
small pieces might be a challenge in some cases.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
DIYer
Oct 21, 2011, 7:49:22 AM10/21/11
to
"Dave N" <dnea...@yahoo.co.uk> wrote in message
news:6b4b646e-9b42-41a8...@t10g2000yqd.googlegroups.com...
Finished my house renovation in August and fortunately have (fingers
crossed) managed to get a quick sale. Readers with long memories may
remember my efforts at replacing the staircase - see
http://groups.google.com/group/uk.d-i-y/browse_thread/thread/76a2dda864730efd
...And, finally, did you need to use the Party Wall etc. Act notice?
crossed) managed to get a quick sale. Readers with long memories may
remember my efforts at replacing the staircase - see
http://groups.google.com/group/uk.d-i-y/browse_thread/thread/76a2dda864730efd
You're effectively raising the height of a party wall, so, yes the Act will
apply. What this means is that you have a legal duty to give notice to your
neighbour, in writing, of the work you intend to carry out. If your
neighbour 'consents' to the work, then that is as far as the Act applies.
Since the fire break will benefit them as well, then, hopefully, commonsense
will prevail. They might also be willing to contribute to the cost (the Act
might actually provide for this).
If your neighbour 'dissents' (say, because you don't like each other) then
that won't stop you doing the work but the Act provides for the appointment
of Party Wall Surveyors. That's when it will start to cost you money.
DIYer
Oct 21, 2011, 7:52:27 AM10/21/11
to
"Dave N" <dnea...@yahoo.co.uk> wrote in message
news:6b4b646e-9b42-41a8...@t10g2000yqd.googlegroups.com...
Finished my house renovation in August and fortunately have (fingers
crossed) managed to get a quick sale. Readers with long memories may
remember my efforts at replacing the staircase - see
http://groups.google.com/group/uk.d-i-y/browse_thread/thread/76a2dda864730efd
crossed) managed to get a quick sale. Readers with long memories may
remember my efforts at replacing the staircase - see
http://groups.google.com/group/uk.d-i-y/browse_thread/thread/76a2dda864730efd
![george [dicegeorge]'s profile photo](http://lh3.googleusercontent.com/a-/ALV-UjVy3egmWxdo6kgdNwXDn-6EE54MDMuR9kO5wF-DhVhewlzxjNY=s40-c)
george [dicegeorge]
Oct 21, 2011, 9:34:39 AM10/21/11
to
What to do at the top of the new firewall?
Should a gap be left for ventilation?
use of plastic to stop moisture from roof wicking down?
and have you got a long enough loft hatch to get plasterboard up there?
]g]
+
Should a gap be left for ventilation?
use of plastic to stop moisture from roof wicking down?
and have you got a long enough loft hatch to get plasterboard up there?
]g]
Dave N
Oct 21, 2011, 1:35:20 PM10/21/11
to
Thanks to everyone for suggestions. I've got a friendly builder
looking at it on Monday with a view to building a block wall - if he
can't fit it in quickly (or really doesn't like the job!) I'll
probably go down the DIY route with a stud wall.
The hatch is 55cm square but the roof void is quite high and spacious
(about 2.4m high at the apex x 7.0m from front to back) so it shoud be
possible to get 2.4 x 1.2m boards in diagonally if I cut them in half
to 0.6m wide. Realistically the firewall will have to sit on top of
the existing party wall, so I expect to need permission from next
door.
I visited the managing agents this afternoon and it turns out that
next door is owned by them. I hope to return tomorrow with a party
wall agreement to sign. They will probably want to get it checked by
their solicitor first but say this should only take a couple of days.
As for the top - I guess the last thing you'd want in a firewall is a
gap. The roof covering is quite new and there is plenty of
ventilation (there was no evidence of dampness, even in winter), so
hopefully moisture wouldn't be a problem.
The idea of building the frame first and cladding the neighbour's side
is interesting, but there are some small obstructions so it would be
difficult to push the structure into place. I could build a stud
wall, clad nearly all the neighbour's side (provided they don't mind)
then fix a couple of battens to the last piece of plasterboard (to act
as fixing brackets) and screw the battens to the studwork, rather than
glue. It will probably be awkward to feed the last piece of
plasterboard through the studwork and pull it back into place, but we
all need a challenge! Just need to be sure that there are no gaps, I
guess?
Finally (for now at least!), I believe the work isn't notifiable to
Building Control if the property was built without a firewall (our
local building control people didn't seem to show much interest but I
didn't ask them outright as I was inquiring about materials). Am I
correct?
looking at it on Monday with a view to building a block wall - if he
can't fit it in quickly (or really doesn't like the job!) I'll
probably go down the DIY route with a stud wall.
The hatch is 55cm square but the roof void is quite high and spacious
(about 2.4m high at the apex x 7.0m from front to back) so it shoud be
possible to get 2.4 x 1.2m boards in diagonally if I cut them in half
to 0.6m wide. Realistically the firewall will have to sit on top of
the existing party wall, so I expect to need permission from next
door.
I visited the managing agents this afternoon and it turns out that
next door is owned by them. I hope to return tomorrow with a party
wall agreement to sign. They will probably want to get it checked by
their solicitor first but say this should only take a couple of days.
As for the top - I guess the last thing you'd want in a firewall is a
gap. The roof covering is quite new and there is plenty of
ventilation (there was no evidence of dampness, even in winter), so
hopefully moisture wouldn't be a problem.
The idea of building the frame first and cladding the neighbour's side
is interesting, but there are some small obstructions so it would be
difficult to push the structure into place. I could build a stud
wall, clad nearly all the neighbour's side (provided they don't mind)
then fix a couple of battens to the last piece of plasterboard (to act
as fixing brackets) and screw the battens to the studwork, rather than
glue. It will probably be awkward to feed the last piece of
plasterboard through the studwork and pull it back into place, but we
all need a challenge! Just need to be sure that there are no gaps, I
guess?
Finally (for now at least!), I believe the work isn't notifiable to
Building Control if the property was built without a firewall (our
local building control people didn't seem to show much interest but I
didn't ask them outright as I was inquiring about materials). Am I
correct?
Hugo Nebula
Oct 21, 2011, 4:00:57 PM10/21/11
to
[Default] On Fri, 21 Oct 2011 10:35:20 -0700 (PDT), a certain
chimpanzee, Dave N <dnea...@yahoo.co.uk>, randomly hit the keyboard
The work would be a material alteration only if it _adversely_ affects
a 'relevant' requirement. The 'relevant' requirements in this case are
structure and fire safety. I can see a hypothetical argument that
adding a masonry wall could put additional loads on the foundations,
but I've never had it applied for any such work. A stud and
plasterboard wall will add virtually no weight to the foundations so
is less likely to fall foul of that requirement.
Perhaps you should take the hint from the lack of interest and assume
that they wouldn't be looking for an application for the work. 90% of
unauthorised works come to light as a result of neighbours complaints,
so if you've got them on board, there's very little likelihood of
Building Control being aware of it. Once your house is sold it's no
longer your problem.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have I strayed"?
chimpanzee, Dave N <dnea...@yahoo.co.uk>, randomly hit the keyboard
and wrote:
>Finally (for now at least!), I believe the work isn't notifiable to
>Building Control if the property was built without a firewall (our
>local building control people didn't seem to show much interest but I
>didn't ask them outright as I was inquiring about materials). Am I
>correct?
This is correct (unless you have a really awkward BC section).
>Finally (for now at least!), I believe the work isn't notifiable to
>Building Control if the property was built without a firewall (our
>local building control people didn't seem to show much interest but I
>didn't ask them outright as I was inquiring about materials). Am I
>correct?
The work would be a material alteration only if it _adversely_ affects
a 'relevant' requirement. The 'relevant' requirements in this case are
structure and fire safety. I can see a hypothetical argument that
adding a masonry wall could put additional loads on the foundations,
but I've never had it applied for any such work. A stud and
plasterboard wall will add virtually no weight to the foundations so
is less likely to fall foul of that requirement.
Perhaps you should take the hint from the lack of interest and assume
that they wouldn't be looking for an application for the work. 90% of
unauthorised works come to light as a result of neighbours complaints,
so if you've got them on board, there's very little likelihood of
Building Control being aware of it. Once your house is sold it's no
longer your problem.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have I strayed"?
Dave N
Oct 21, 2011, 6:14:07 PM10/21/11
to
Thanks, Hugo - I thought that might be the case. The only concern I
have is that I might be pressed for a BC certificate by the bank's
appointed surveyor (either instead of an re-inspection or in
addition). I guess that if most BC departments take the view that an
application isn't required the surveyor would agree with this (I must
add at this point that I had a chat with the surveyor I originally
employed when I bought the house and he said the work would be
notifiable - but, of course, I suspect he was covering his @rse and
being cautious - my only concern is whether another surveyor would say
the same)...
have is that I might be pressed for a BC certificate by the bank's
appointed surveyor (either instead of an re-inspection or in
addition). I guess that if most BC departments take the view that an
application isn't required the surveyor would agree with this (I must
add at this point that I had a chat with the surveyor I originally
employed when I bought the house and he said the work would be
notifiable - but, of course, I suspect he was covering his @rse and
being cautious - my only concern is whether another surveyor would say
the same)...
Hugo Nebula
Oct 22, 2011, 6:10:33 AM10/22/11
to
[Default] On Fri, 21 Oct 2011 15:14:07 -0700 (PDT), a certain
I suggest then that you ring your local authority up and, without
giving your address, ask whether an application would be required. If
the answer is no, then write or email (including your address), asking
the same question. You will then get a reply in writing saying that
the work does not require an application.
giving your address, ask whether an application would be required. If
the answer is no, then write or email (including your address), asking
the same question. You will then get a reply in writing saying that
the work does not require an application.
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