OK...the garage conversion is actually happening. All of the external
building work is complete. :-)
I've now got to do the floor. I was going to lay 50x125 wooden beams at
400crs, and infill with Celotex XR3120. But when the guy from Building
Control came to inspect the external building works, I spoke to him and he
suggested to me that it would actually be far easier for me, if I simply
laid the Celotex wall-to-wall (without the timbers), and then put a
damp-proof membrane over the top, then topped it all with 22.5mm T&G
chipboard, which is glued together. He said that if done this way, the floor
will move a micron in it's lifetime.
So that's what I'm now doing - I'm not going to argue, especially if it's
making my life easier. However, I have a wee problemette...
The Celotex is 2400mm x 1200mm. The garage is 4900mm x 2480mm internally.
Effectively, having laid four slabs of Celotex, I would have 100mm gap at
the end, and 80mm gap at the side. So I need a fifth slab of Celotex. I'm no
expert, but I do wonder whether cutting what would be thin slivers of
Celotex (compared to the 2400x1200 slabs), and slotting them in at the sides
is really the way to go. Or whether I should aim for less complete slabs,
but overall, bigger slabs wherever used.
I hope that makes sense? Does anyone have any idea? I will then also have a
similar problem with the T&G floorboard, but with that, I can see definite
benefits to cutting them in half, as then I can put the flat sides of the
boarding next to the wall (well, 6-10mm away).