I'm dividing an existing garage in two. Half will extend the utility room and half will be a bicycle store leaving the existing up and over door in place. My question is from what do I need to construct the dividing wall? Is stud work and plaster board OK or does it need to be brick?
Nope I have registered with local Building Control, but it's DIY and I would like to to sound a bit knowledgeable on his first visit. I have done this stuff before but not under the watchful eye of BC. What timber size is best for stud work, and as there is a door in this wall joining the utility room and bicycle store does this need to be a firedoor?
A lot will be down to getting the insulation up to spec. Is the floor lower in the garage? I don't know the requirements of the top of my head...but others on here will...so hang tight
Thanks GGN Here are my proposals for the rest of the extended room. Floor Existing concrete raft is 170mm below the utility floor. Propose DPC membrane on it then 400mm centred treated timbers (150mm), filled with rockwool, and topped by 20mm flooring chipboard. Two air bricks installed under new floor. Ceiling Existing flat roof is on 140mm timbers. Propose filling gap with rockwool and installing plaster board over (thickness/foil backed?) Side wall 1 is internal Propose just plastering the wall Side wall 2 is single brick external which in 15 years has never shown any signs of damp Propose DPC membrane against brickwork with treated battens (thickness?) screwed to brickwork, filled with insulation (polystyrene/celotex?) and covered in foil backed plasterboard Any comments would be most welcome particularly where I have question marks? Remember BC are watching Thanks
You could put 150mm of celotex down on the floor, foil tape the joins and put moisture resistant caber flooring on that. Generally put 20mm around the edges.
Remember to leave a air gap between under side of decking & insulation,(usually 50mm) as it will be a cold roof design,(so old fashion) you will need to ventilate roof on two opposing sides along its length. And I also prefer 150mm Celotex on floor to rockwool.
Thanks guys, the air gap in the roof is noted. If I understand it correctly you are suggesting the use of Celotex alone for the floor support. My concern is that the new floor structure may compress a little under the weight of the cupboards and appliances and may make a seamless joint difficult with the existing solid concrete floor of the existing utility room. I am imagining a bit of movement in the Celotex. What do you think?
How can there be movement/compression in Celotex, sitting between 150mm joists & cover with 20mm flooring chipboard.
I thought the suggestion was to have a fully floating floor on Cellotex without a timber structure underneath
You can do it either way...although if celotex directly on floor then it needs to be very flat. Btw, is garage floor on a gentle slope...they often are? If that's the case, then joists may be better option, or firring strips cut accordingly.
Thanks good people, I think I have enough info to talk to BC with some authority, but still welcome any other comments.
When I started many moons ago, I used to paint floor & about 300mm up the wall with a liquid dpm,which would stop any water seeping under the block/brick work, (tanking) if it was built on a slab, this would stop any water getting under the plastic dpm. Followed by a layer of plastic visqueen dpm,again 300mm up the wall,then laid the joists on it & used spacers where need to level joists.
Makes me feel even older than I am, but old school ways are sometimes better. Had to replace several floating floors over the years where the water got in & started rotting the joists, tanking using Synthaproof or similar makes the area 100% water proof. Use to 2mm, 4mm ply strips,usually from old ply flush doors we rip down, before the plastic spacers became popular.
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