Loft firewall construction

[Dave N]

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

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 =A3150 + labour) or a timber stud wall with fire retardant plasterboard cladding (materials would be about =A3150 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]

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.

NT

[Andrew Gabriel]

Would need to be a glue that didn't let-go in a fire.

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.

[DIYer]

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]

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.

[george [dicegeorge]]

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]

+

[Hugo Nebula]

This is correct (unless you have a really awkward BC section).

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.

[Dave N]

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)...

[Hugo Nebula]

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.