Insulating a boarded loft?
Discussion
Part of the loft in my dormer bungalow was boarded over by a previous owner.
The boarded area extends over the second bedroom, integral garage, and half of the bathroom. I want to improve the insulation over the bedroom and bathroom.
The boarding is t&g chipboard, nailed in place - lots of nails, look like clout nails? I think removing the boards would be a big job, possibly damaging the ceilings below, and probably damaging the boards too.
Any options for over-boarding on top of the existing boards with Celotex/space blankets or similar?
Or should I just refill the loft space with boxes of stuff?
It's about 150 sq ft that needs insulating
The boarded area extends over the second bedroom, integral garage, and half of the bathroom. I want to improve the insulation over the bedroom and bathroom.
The boarding is t&g chipboard, nailed in place - lots of nails, look like clout nails? I think removing the boards would be a big job, possibly damaging the ceilings below, and probably damaging the boards too.
Any options for over-boarding on top of the existing boards with Celotex/space blankets or similar?
Or should I just refill the loft space with boxes of stuff?
It's about 150 sq ft that needs insulating
I think it's just the original stuff from when it was built, maybe 50mm?
Would something like this work, if laid over the existing boards?
https://constructionmegastore.co.uk/products/insul...
Would something like this work, if laid over the existing boards?
https://constructionmegastore.co.uk/products/insul...
Similar question
I've got similar, pine and groove flooring over half the loft, 45 year old house with original insulation to the top of the rafters and boarded over the top.
Over the part that isn't boarded I've increased the insulation by laying extra at 90 degrees to the rafters, but only a few rolls at probably 200mm.
I don't want to raise the floor either.
Would I be better putting in something like kingspan between the roof rafters?
More insulation on the unboarded part and just put as much boxed storage on the boarded...
I've got similar, pine and groove flooring over half the loft, 45 year old house with original insulation to the top of the rafters and boarded over the top.
Over the part that isn't boarded I've increased the insulation by laying extra at 90 degrees to the rafters, but only a few rolls at probably 200mm.
I don't want to raise the floor either.
Would I be better putting in something like kingspan between the roof rafters?
More insulation on the unboarded part and just put as much boxed storage on the boarded...
If you insulate at rafter level, you need adequate ventilation above the insulation, and a vapour barrier at the bottom of it.
It's not easy to do properly.
My loft floor in the previous house was nailed down using ring nails.
I drilled the heads off the nails to lift the boards.
You don't have to lift all the boards, you can poke insulation under some boards.
It's not easy to do properly.
My loft floor in the previous house was nailed down using ring nails.
I drilled the heads off the nails to lift the boards.
You don't have to lift all the boards, you can poke insulation under some boards.
I have similar setup - dormer bungalow, boarded eaves/loft with 18mm chipboard nailed and grooved. Ceilings are below. On top of the ceilings, and below the chipboard, is approx 100mm of rockwool type insulation. The joist depth is 300mm so there is quite an air gap above the insulation, but it doesn't continue to the upstairs walls, so there is a gale blowing between the joists.
I sacrificed the storage space and just put 300mm of rockwool over the boards above the front two rooms where the wall insulation is particularly poor, and lapped to the wall cavities which are open and have 50mm of polystyrene board insulation in them. It made a big difference to the front two rooms. I have lots of eaves storage still, so it wasn't a big deal to lose that space.
I sacrificed the storage space and just put 300mm of rockwool over the boards above the front two rooms where the wall insulation is particularly poor, and lapped to the wall cavities which are open and have 50mm of polystyrene board insulation in them. It made a big difference to the front two rooms. I have lots of eaves storage still, so it wasn't a big deal to lose that space.
I laid Cellotex on top of the boards, then put some plywood on top of the Cellotex. Fine for storing stuff and walking on. Only issue is getting the Cellotex up through the loft hatch, had to cut it down the middle. Most of mine came out of skips and off building sites. It's not cheap to buy.
The existing boards don't go right up over the tops of the blockwork wall skins. I can see both leaves, and the cavity insulation, at the edges of the boards. If I just go over the existing boards with the insulation board, it should still ventilate OK - there are circular soffit vents every metre all around the house. It's a hip roof, and the existing boards don't quite butt up against the rafters.
Would that be OK?
10 years ago, I would've done it myself. Knees and back aren't really up to it these days, so I've got to get someone in to do it.
I'd prefer not to lose too much storage space - the lego boxes and unbuilt model kits have got to live somewhere.
Would that be OK?
10 years ago, I would've done it myself. Knees and back aren't really up to it these days, so I've got to get someone in to do it.
I'd prefer not to lose too much storage space - the lego boxes and unbuilt model kits have got to live somewhere.
megaphone said:
I laid Cellotex on top of the boards, then put some plywood on top of the Cellotex. Fine for storing stuff and walking on. Only issue is getting the Cellotex up through the loft hatch, had to cut it down the middle. Most of mine came out of skips and off building sites. It's not cheap to buy.
this is the easy answer.Coming back to this, I'm going to get someone in to do the job - my back and knees just aren't up to it anymore.
Plan is to lift the boards and do it properly.
Something I need to consider is, what type of insulation should be laid before the boards go back down - rigid (Celotex) or rock wool (Knauf)?
The rooms below the boarded loft are fitted with LED downlights, Aurora FD102 and FD103 GU10.
Rigid seems to be twice as good at insulating (for the same thickness), but would it be OK to just cut it around the downlights? Any problems with it getting hot, or from making holes in the vapour barrier?
Rockwool might be the safer option, just pull it away from the light fittings to leave a bit of space?
I don't think there's enough depth between the boarding and the plasterboard to fit any kind of cap over the lights.
Plan is to lift the boards and do it properly.
Something I need to consider is, what type of insulation should be laid before the boards go back down - rigid (Celotex) or rock wool (Knauf)?
The rooms below the boarded loft are fitted with LED downlights, Aurora FD102 and FD103 GU10.
Rigid seems to be twice as good at insulating (for the same thickness), but would it be OK to just cut it around the downlights? Any problems with it getting hot, or from making holes in the vapour barrier?
Rockwool might be the safer option, just pull it away from the light fittings to leave a bit of space?
I don't think there's enough depth between the boarding and the plasterboard to fit any kind of cap over the lights.
Be careful of weight. Ceiling ties aren't meant to carry any meaningful load.
Lifting existing boards is a good step as you will avoid the weight of a second layer.
I would avoid anything rigid as it will be an real b
d of a job (there's a reason DIY loft boards are 300mm wide).
Go or rockwool, recycled plastic, sheep wool, etc., with the boards lifted above it by those plastic legs you can get for exactly this reason.
Be careful not to block any ventilation that may be present at the eaves.
Lifting existing boards is a good step as you will avoid the weight of a second layer.
I would avoid anything rigid as it will be an real b
d of a job (there's a reason DIY loft boards are 300mm wide).Go or rockwool, recycled plastic, sheep wool, etc., with the boards lifted above it by those plastic legs you can get for exactly this reason.
Be careful not to block any ventilation that may be present at the eaves.
I don't think there's enough depth to fit loft lids - they are 6" high, I think the gap is just under 5".
I had the soffits redone last year, there are about 45 circular vents fitted - one every metre. I've already checked that the insulation doesn't extend past the cavity, so the soffits are clear.
I'm basically doing this to reduce the overnight temperature drops in the rooms, when the heating is off.
The bedroom that's boarded over isn't actually that bad, only dropping 1 degree.
The bathroom drops 3 degrees, so definitely needs sorting.
The lounge (not boarded) drops 2 degrees, and is very slow to warm up. Cheap and easy to insulated.
I think it might be worth just getting the bathroom and lounge done, with 200mm rockwool.
The lounge just needs to be loose laid, and easy to fit loft lids over the downlighters.
The bathroom is only half boarded, and the boards sit about 4" higher than in the adjacent bedroom - plenty of height for insulation and a couple of loft lids.
The boards sit higher because of the extra-deep joists added to carry the dormer conversion.
I had the soffits redone last year, there are about 45 circular vents fitted - one every metre. I've already checked that the insulation doesn't extend past the cavity, so the soffits are clear.
I'm basically doing this to reduce the overnight temperature drops in the rooms, when the heating is off.
The bedroom that's boarded over isn't actually that bad, only dropping 1 degree.
The bathroom drops 3 degrees, so definitely needs sorting.
The lounge (not boarded) drops 2 degrees, and is very slow to warm up. Cheap and easy to insulated.
I think it might be worth just getting the bathroom and lounge done, with 200mm rockwool.
The lounge just needs to be loose laid, and easy to fit loft lids over the downlighters.
The bathroom is only half boarded, and the boards sit about 4" higher than in the adjacent bedroom - plenty of height for insulation and a couple of loft lids.
The boards sit higher because of the extra-deep joists added to carry the dormer conversion.
Did this a couple of yrs back - was originally only insulated up to the 4" ceiling joists. Left that all down and chucked 200mm one way, then 100mm the other way over everything.
Also put loft legs down across one area and built a floating platform so I could store junk up there - quite why I didnt just throw everything out I don't know.
Took a weekend to do. Got everything from Homebase iirc.
shtu said:
They should do the trick - thanksGassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff