I am replacing the old storage tank in the loft.
The existing vent pipe from the indirect cylinder below is not high enough above the tank water level so I will need to extend it. Also the existing 180 degree vent pipe U-bend has been formed with two elbow connectors and short lengths of...
My joists are spaced at 12" centres and there is no sign of this happenning so far. If it does become a problem I'll lift the Celotex (easy) and fit a layer of 6mm ply over the joists.
Yes, I don't think laying Celotex without additional support would work in that case.
I have 2 x 4 ceiling joists with 4" mineral wool laid between. I'm adding 100mm Celotex resting on the joists and will eventually lay boards over the Celotex. The only slight problems so far have been needing to pack up some of the joists to get them level, and having to add noggings to support...