firewall in roofspace

[sue gazzard]

Hi, can anyone advise easiest/cheapest/lightest way to construct a suitable firewall in the roofspace of my building please? background is that it was originally constructed as one dwelling but has long been used as two and unfortunately I can't afford for it not to be; insurance and security demand that there is a firewall separating the two halves but I am concerned about a builders proposal to construct this as a plasterboarded stud wall with fibreglass insulation.....(but happy to be told I shouldn't worry if I shouldn't worry....) :? :?

 

[Penners]

The first house that my daughter bought was a new-build end-of-terrace (about 10 years ago). Its loft firewall was plasterboard on studwork, and presumably passed building control.

What's the construction of the house? If your firewall will be built on top of a load-bearing masonry wall, then it should have no trouble carrying the weight of a lightweight (ie: air-entrained) concrete block structure, if this is what you prefer (as I think I would!).

If you're listed, don't forget LBC.

 

[arthurw3]

I have used both a stud wall with 12mm plasterboard both sides, (gives 30min fire protection) and a celcon lightweight block wall off a brick wall.

 

[dandrew]

One option is to use a fire curtain hung from the ridgeboard. It is composed of lots of layers incorporating fire retardant, some silvery foil and lots of other things. The problem is that in a small cramped space it's a hellish job. The stuff wieghs a ton and you've got to screw it into place through angled aluminium (the sort used to make office partitions) . Definitely a 2 person job, but it will give you an hour's fire resistance.

May be worth looking into if space is not too problematic

 

[Penners]

Judging by your description, a lightweight block wall actually sounds a great deal easier.

 

[sue gazzard]

Hi Penners, thanks for this. It's actually a timber-framed building and the site of the firewall will be either side of the chimney structure. Whaddya think? Should I just go with the stud wall?

 

[Penners]

What will your firewall rest on? Is there a wall/walls on the floor below, that it can rest on? Or will it simply be filling in a triangular space between a first-floor ceiling joist and two rafters, with no further support beneath the joist?