We're having a small extension + kitchen/dining room wall taken out to make one open plan space.
The existing building (1938) has mostly vented timber flooring, though in the kitchen a small area is concrete (and I suspect under the cabinets is, too).
As ever, the flooring has competing desires :
- floor surface to be herringbone parquet-*style* (but using engineered blocks)
- FFL to be the same as the rest of the house
- to insulate from the cold
- wouldn't UFH be nice. (Wet, as IMHO it's the only system that makes any sense)
My initial plan was to take the existing floorboards out, skim 18mm off the tops, put a plywood subfloor on top then flooring on top of that (because of small blocks of the floor shape). Underneath use retro-fit wet UFH system (fill out with celotex, pipes through dry mix on top).
I lifted a few boards to have a look-see. The floor joists are about 98mm (so I guess a nominal 4"), then there's a ~230mm void, then concrete.
My feelings are that if I trim the joists, there's not a lot of room for insulation and something for thermal mass - plus it's a big ask for heat to go through the plywood *and* the engineered floor.
I've seen a different system that routes pipe through the subfloor and has 'heat plates', which is perhaps an option, but I wonder if it's going to work terribly well.
My secondary thought was - given the ground under the void is concrete rather than soil - and we'll need a new floor anyway for the extension pad - perhaps just continue on and make the entire area a 'modern' era construction (concrete, insulation, screed).
My query is about what would need to be done for damp-proofing around the edges, re-enforcement requirements, build-up (350mm is relatively deep, whether to put extra thick layer of concrete, more insulation, etc). The rooms surrounding it all have external walls, so will continue to be ventilated.
The existing building (1938) has mostly vented timber flooring, though in the kitchen a small area is concrete (and I suspect under the cabinets is, too).
As ever, the flooring has competing desires :
- floor surface to be herringbone parquet-*style* (but using engineered blocks)
- FFL to be the same as the rest of the house
- to insulate from the cold
- wouldn't UFH be nice. (Wet, as IMHO it's the only system that makes any sense)
My initial plan was to take the existing floorboards out, skim 18mm off the tops, put a plywood subfloor on top then flooring on top of that (because of small blocks of the floor shape). Underneath use retro-fit wet UFH system (fill out with celotex, pipes through dry mix on top).
I lifted a few boards to have a look-see. The floor joists are about 98mm (so I guess a nominal 4"), then there's a ~230mm void, then concrete.
My feelings are that if I trim the joists, there's not a lot of room for insulation and something for thermal mass - plus it's a big ask for heat to go through the plywood *and* the engineered floor.
I've seen a different system that routes pipe through the subfloor and has 'heat plates', which is perhaps an option, but I wonder if it's going to work terribly well.
My secondary thought was - given the ground under the void is concrete rather than soil - and we'll need a new floor anyway for the extension pad - perhaps just continue on and make the entire area a 'modern' era construction (concrete, insulation, screed).
My query is about what would need to be done for damp-proofing around the edges, re-enforcement requirements, build-up (350mm is relatively deep, whether to put extra thick layer of concrete, more insulation, etc). The rooms surrounding it all have external walls, so will continue to be ventilated.
