Hi all,
I'm about to embark on a project of raising a concrete floor by around 85mm so that its new FFL sits at the same height as the rest of the ground floor of our house.
As I have this much depth to play with, I'd like to take the opportunity to put some insulation down so as to help make the room feel warmer. The air temperature in there at the moment is ok, but being a concrete floor, your feet tend to feel the chill the most.
In order to accommodate the insulation, I feel it best to adopt a beam and board method of raising the floor. i.e. Have a number of wooden beams that sit on the concrete floor, spaced appropriately to allow the gap between them to be filled with rigid celotex type insulation and then floor boards on top.
I do however have a few questions:
1. Does this sound like a good idea?
2. If ok, what type of wood should I be using for the beams and boards? For the boards I would like to put down proper floor boards rather than a chipboard or plywood. Is there any major problem doing this?
3. I expect the beams to be roughly 65mm deep. How wide do they need to be if positioned at approx 400mm centres? Somewhere between 25 and 50mm perhaps?
4. For the beams that run the perimeter of the room, should they be screwed to the walls as well as the floor or should I leave an expansion gap at the perimeter?
5. Should I put down a polythene DPM over the concrete? I'm hoping that there is a DPM in there somewhere already but how can you tell? There was carpet in the room until yesterday and when I lifted it, there were two small areas that were a little damp. Having left it a day or so now, they've completely dried up. Would me adding a DPM to one that is already there cause problems? Or can you never have too many?
Here's a rough sketch of the room to help get a scale:
https://imageshack.com/a/img924/97/bvpkiV.jpg
You can ignore the -125mm reference. Having now stripped the room, the fall in the floor isn't quite this bad although some packing is going to be needed down towards the dog leg end of the room.
The finished floor will be laminate for now but could be carpet or vinyl in the future, maybe even tiled, you never know.
Thanks for any assistance you can provide
I'm about to embark on a project of raising a concrete floor by around 85mm so that its new FFL sits at the same height as the rest of the ground floor of our house.
As I have this much depth to play with, I'd like to take the opportunity to put some insulation down so as to help make the room feel warmer. The air temperature in there at the moment is ok, but being a concrete floor, your feet tend to feel the chill the most.
In order to accommodate the insulation, I feel it best to adopt a beam and board method of raising the floor. i.e. Have a number of wooden beams that sit on the concrete floor, spaced appropriately to allow the gap between them to be filled with rigid celotex type insulation and then floor boards on top.
I do however have a few questions:
1. Does this sound like a good idea?
2. If ok, what type of wood should I be using for the beams and boards? For the boards I would like to put down proper floor boards rather than a chipboard or plywood. Is there any major problem doing this?
3. I expect the beams to be roughly 65mm deep. How wide do they need to be if positioned at approx 400mm centres? Somewhere between 25 and 50mm perhaps?
4. For the beams that run the perimeter of the room, should they be screwed to the walls as well as the floor or should I leave an expansion gap at the perimeter?
5. Should I put down a polythene DPM over the concrete? I'm hoping that there is a DPM in there somewhere already but how can you tell? There was carpet in the room until yesterday and when I lifted it, there were two small areas that were a little damp. Having left it a day or so now, they've completely dried up. Would me adding a DPM to one that is already there cause problems? Or can you never have too many?
Here's a rough sketch of the room to help get a scale:
https://imageshack.com/a/img924/97/bvpkiV.jpg
You can ignore the -125mm reference. Having now stripped the room, the fall in the floor isn't quite this bad although some packing is going to be needed down towards the dog leg end of the room.
The finished floor will be laminate for now but could be carpet or vinyl in the future, maybe even tiled, you never know.
Thanks for any assistance you can provide
