Lounge floor insulation - pictures as requested

[David]

So far we have cleared out the floor boards for the first run of OSB3 to go back down.

It is already obvious that lifting the whole old floor at one go is probably not a good idea as quite a bit of the rigidity for the joists is due to the flooring nailed to it. The joists are just laid on wooden bearers with a nail or two so they can wobble a little bit.

A couple of especially wobbly short pieces to the side of the fire place.

One "interesting" feature - one side of the fire place and the middle dwarf supporting wall have a piece of narrow wood running along the middle as a spacer to raise the joist. My first guess is that the level for the middle wall was taken from the fire place and not the side supporting dwarf wall so the bearers around the fireplace and along the middle of the room were a bit low compared to the ends. As far as I can tell it has all been there doing fine since the 1930s so presumably it is fine now as well.

Next tasks (apart from cleaning out the last few nails - I could knock them in but there is an obvious history of nails getting bent over instead and leaving high spots) is moving some wires which are nailed to the sides of the joists an putting in a new piece of wood across the fireplace area where the concrete hearth used to be.

Then I have to run in the speaker cables which are to come up through the floor.

After that comes the fitting of the Celotex, foaming, and shaping the floor around the doorway before fitting.

I plan to only put a couple of screws in each 8 * 4 new floor board until the whole thing is laid, so it is held firmly but can be unscrewed should micro adjustment be needed when I get to the other side of the room.

It should take three runs of board to do the main room (room is 3500mm and {3 * 1220} is 3660) and I haven't decided if it is worth centring the middle run and trimming both sides, or just going full boards with the third board cut down one side and fitting partially into the semi circular bay. This makes for less cutting but the joint lines may look a bit off.

More photos as it progresses.

Cheers

Dave R

[fred]

In article , David writes

Thanks for the update and pics.

When laying the big boards, lay them across the joists as they will be fitted but with a little bit of the joist showing each end and mark the edges of them with a marker pen at each end, it will help with finding them when screwing down the boards for real and all clues are hidden. Slide back into place before fixing.

One other thought, you may wish to lay your 8x4s in the centre of the room and use cut pieces as a border that can go under the skirting. That way, if you have to lift the big boards then they wont be stuck under skirting and perhaps your floor mounted speaker points will be on the fixed border and not be disturbed by any further lifting.

[harryagain]

None of the above would be relevant if you'd got proper T&G flooring. There would be no waste, less expense, less work and a better/stronger job.