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[matt-sboro]

does anybody know anything about spray foaming?

i just got a verbal quote over the phone for a 2inch thick covering of my internal roof space (just the roof not the whole loft)

and he said roughly about £1750

now all i want is a insulating covering then plasterboard so i can use my loft space for my gym equipment without getting covered in horrible dust

i have just seen a DIY kit (medium tank 200sq/ft @25mm) for £180

anyone help?

[Marks DTM Calib]

does anybody know anything about spray foaming?

i just got a verbal quote over the phone for a 2inch thick covering of my internal roof space (just the roof not the whole loft)

and he said roughly about £1750

now all i want is a insulating covering then plasterboard so i can use my loft space for my gym equipment without getting covered in horrible dust

i have just seen a DIY kit (medium tank 200sq/ft @25mm) for £180

anyone help?

I have a few issues with spray foam insulation the main one being, how do the roof joists remain dry and well ventilated to stop them rotting!

My recommendation would be to use some celotex sheet (available in different thicknesses) to place between the rafters whilst still leaving at least a 1-2 inch gap between the insulation and the felt/tiles to suppurt airflow through the roof.

It will also be cheaper than what you were quoted, probably better insulating, less messy to install etc.

[MikeDundee]

Marks is correct this is the way we apply the building regs, when replacing roof coverings. However, in your case your not replacing the roof covering. but what Marks has suggested is the correct way to do it, and as said a lot cheaper and you can do it yourself

[Martin_1962]

I insulated the floor of a mobile home (my parents) with bin bags with rockwool in them stapled to the joists, then boxed in with hardboard - something similar might work for a roof

[matt-sboro]

would these celotex sheets just nail/screw over the rafters like a plasterboard sheet?


also - my loft has next to no ventilationas i have a broken condensation unit in my loft - am i ok to add ridge vents to give enough ventilation to my roof space?

[Snips]

have u had the floor joists replaced in the loft? as normally loft floors are not weight rated, and you could end up falling through!

[matt-sboro]

i have braced the roof joists to each other and also supported it from the main beams that go from side to side so its safe enough up there.

my house is 80 years old too so it was built with the proper materials!!

i've got 2 10inch by 5inch beams that go from 1 side to the other!

[Ken T]

would these celotex sheets just nail/screw over the rafters like a plasterboard sheet?


also - my loft has next to no ventilationas i have a broken condensation unit in my loft - am i ok to add ridge vents to give enough ventilation to my roof space?

I would echo what Mark said. You need to leave 1" breathing space between tiles and insulation for any water to get blown out. Nailing onto rafters is fine, but if you go for the Building Reg amount, its something like 4" so your room will be smaller by 8". If yo have a look at Celotex and Kingspan's sites they have plenty leaflets about how they recomend to do it. There are some sellers on fleabay who sell slightly damaged sheets sheets of insulation, and if you hunt you can get it at a very good price. I got stuff from "secondsandco" who has a fair amount on sale at present   http://cgi.ebay.co.uk/Kingspan-Insulation-Board-60-90mm-Phenolic-Mixed-Lot_W0QQitemZ290253021626QQihZ019QQcategoryZ63894QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Have fun, its a tremendously shitty job up there in the dust and muck, trying to fit a huge piece of insulation between the raters and not go thro the floor at the same time. And then you have to somehow hold it in position while you struggle trying to put in 6 or 8" screws to hold it up, and then you have to put plasterboard up on top, and try and find where the rafters are to put the screw in, cause plasterboard nails won't hold in insulation.  

Best of luck  

Cheers Ken

[Elite Pete]

I would screw then to the rafters rather than nail as you could loose some tiles

[Marks DTM Calib]

I wouldn;t bother with seconds any more, its dropped in price a lot now so most builders merchants will supply a 2 inch sheet for about 18 quid.

[Matchless]

Do you have felt under your roof tiles or slates?
Is there sufficient height to create a horizontal ceiling with space below the ridgeboard?

The building regs specify a minimum 50mm / 2" continuous air space between the insulation and the under felt but this assumes that you also have vents at the eaves and a ventilated ridge which you wont have unless you have re-roofed recently.
If you cant provide the continuous ridge vent then you must ensure that you have a gap below the ridgeboard to allow some cross ventilation.
Dont ignore the ventilation issues, you could end up with rotten roof timbers.

[Vamps]

have u had the floor joists replaced in the loft? as normally loft floors are not weight rated, and you could end up falling through!

I worry about that everytime I look at the amount of stuff, mostly junk, that we have in there.

[HerefordElite]

ideally you would run 50x50mm battens up the rafters to provide your minimum 2" (50mm) air ventilation gap. Is this a true room in the roof conversion (do you have/ need planning permission)?

Specced a job today with 130mm Celotex between rafters and 40mm under to achieve 0.14w/m2 U-value (i design timber frame buldings)
free plug : http://www.taylor-lane.co.uk/

I would be very very careful if you are putting GYM equipment up there, sounds a bit heavy :-?

[Vamps]

ideally you would run 50x50mm battens up the rafters to provide your minimum 2" (50mm) air ventilation gap. Is this a true room in the roof conversion (do you have/ need planning permission)?

Specced a job today with 130mm Celotex between rafters and 40mm under to achieve 0.14w/m2 U-value (i design timber frame buldings)
free plug : http://www.taylor-lane.co.uk/

I would be very very careful if you are putting GYM equipment up there, sounds a bit heavy :-?

Is that a new name for Wii          

[matt-sboro]

i can actually see the roof tiles from inside my loft with cement plugging the gaps - so there is no felt

i've not put much up there - just my bench and its sat by the chimney which is supporting some joists and over one of the stud walls - so its very well supported up there with all the extra supporting i have done.

its not a proper room - i have fitted a big loft hatch and just wanted to make it fairly warm in the winter with something to stop me getting a mouth full of 80 year old dust in me gob!

and maybe a couple of velux windows for the summer