Timber stud as a fire wall?

[redders1]

I am about to begin an extension that requires "stealing" roughly 1m from the rear of my garage. This 1m stolen from the garage will become part of a new utility room.
As the new wall seperating the end of the garage and the new utility room needs to be a fire wall to meet building regs the architect has specified building it in 200mm blockwork. This will obviously require the old garage floor being dug up and foundations digging.

The question I would like to ask is could this wall be built out of timber studwork and still meet the building regs required for a fire wall? This would obviously save me the time and effort of digging up the floor and digging foundations. It would also save me a fair amount of money.

The only issue I can see is that I am not sure whether the current garage floor that would become the first 1m of the new utility room has a dpm. If it hasn't could I chip the 2 inch screed off and continue the new dpm that i will put down when I construct the extension over this old part of the garage floor and the re screed it?

Any advice would be welcome.

 

[kevindgas]

what fire resistance time is required?
there is plasterboard that is foil on 1 side would this meet your requirements?

 

[redders1]

I am not sure what time is required. I assume 30 mins or 1 hour max.

 

[^woody^]

Get your designer to specify a timber stud wall with the required fire resistance - ie 12.5mm board and 5mm skim each side with rockwool internally. This is what you are paying him for

However, from the information in your post, then the wall will most likely need to conform to part L1a (i.e. thermal resistance) and it should be treated as an external wall and insulated as such

Same for the floor which is in the utility - so its not just a case of inserting a DPM - it may need insulating too

 

[ColJack]

you build it out of metal studwork ( your local DIY shed will probably carry it.), then double board it ( stagering the joints.. ).

I believe that you can also get fire resistant plasterboard ( the pink stuff? )

 

[redders1]

Thanks for that Woody. I forgot about the floor insulation, so it looks like the old garage floor will have to come up. But at least I should save on digging foundations and building the wall from blockwork.
Will also look into the metal studwork ColJack suggests.

Meeting architect on Tues so at least I am pre armed. Cheers guys.

 

[^woody^]

The garage floor is most likely lower than the existing house (or new) floor, so can normally be insulated on top.

Metal stud is just a different way of doing it and offers no advantage to timber, and is not a requirement for a fire resisting wall.

All plasterboard is fire resisting, its just a matter of how long for. There is no need for pink boards