Hi All, first post, so take it easy on me... just replacing floorboards in a suspend wood floor and notice a lot rubble and sand. So I need too remove as some is only 10cm under the joists? Also can I move it to the middle where the void is three feet down or should I skip it? Also the room smells damp but not had heating in this room and no air vents under flooring. Plan was: Put in several air vents Replace two rotten joists. Place dpm under current joist in contact with the bricks. Insulate between joists with rigged kingspan. Lay down chipboard flooring. And then new flooring. should I put a damp membrane above the insulation? Or should I leave it as we would rather the room breathes? Should I spray down any mould under the floor to kill before doing the work? Should I wrap the ends of the joists with dpm or just put it under them? Do the treated joists also need me to treat with anything?
No need for dpm Yes, treat any mould Yes, wrap the joist ends Treat any cut ends, with a suitable timber treatment Minimum 150mm required under the joists, so you can move the excess to the middle
You may want to consider spraying the rubble with either a bleach or disinfectant solution, whilst treating the mould
D Do the job properly and put timber floorboards back. The only thing chipboard flooring is good for, is lining the sides of a skip to get a bit more in, it is then consigned to the dump which is the best place for it.
hi Abrickie, can I ask as well can I just lay the new joists on top of the bricks the same as the old hoist or do they need fixing/brackets
Just the same as the old ones, although your new ones may need wedging up a little ( metric v imperial sizing) broadfix packers are your friend for that
thanks pal that’s what I thought Yeah the new joists are slightly smaller 100mm by 75 and the old ones 100mm x 80. Will that be fine and should I go with C24 or C16 treated.
C24 , without knowing the span you may be ok with c16 but there’s no difference in cost, don’t worry about 5mm just pack up
Another couple of questions. If only half a joist is rotten can I cut it back to the dwarf wall up the middle of the room and then run a new joist beside it from the dwarf wall To the other side? Would I need to join them or have them overhand a certain amount. also if I’m only replacing a limited amount of joists do I need to inform building control? I’m planning to insulate as per regs? cheers again
Yes you can just do half a joist, as long as they are sitting over the full width of the dwarf wall that’s good enough. No need for BCO for only a couple of joists