Insulating below exisitng ceiling below flat roof (rather then tearing down perfectly sound ceilings)

I have a large area of flat roofed accommodation (dining room 22m2,
kitchen 14m2 and utility room 9m2). The existing insulation over all
the flat roof area appears to be 1" of fibreglass!
I've just installed Celotex between the rafters of 2 bedrooms after the
ceiling had to be taken down due to a leak in the flat roof (yes, I have
an AWFUL LOT of flat roof!). Seems a good and simple solution in a case
where the ceiling has to come down anyway.
I really don't want to have to tear down the perfectly sound ceilings in
these other rooms, but I'm conscious of the enormous heat loss that must
be taking place with the pathetic original insulation. (The external
covering is less than 2 years old, so I don't want to spend a lot of
money having that redone for a warm deck solution!)
It seems however that I have only two options - one is to tear down the
ceilings, insulate between and below the joists and have the ceiling
reboarded and finished.
The second option - because these ceilings are very high compared to
the rest of the house and I have 170mm to play with under the existing
ceilings while still maintaining headroom the same as the rest of the
ground floor - is to follow the "advice" from Celotex to fix 150mm
"battens" at 600mm centres, insulate between with 150 mm and board and
This second option seems to be as expensive (although less dirty) than
tearing down the existing ceilings and insulating between and below the
existing joists. Can anyone suggest an economic and practical solution?
I am a competent diy'er and cost my time at £0 as I am retired, but
would need a professional to board and finish and have no help available
to fix 6x2" 6m long "battens" under the existing dining room ceiling!
I couldn't get a coherent answer from Celotex to my question about
vapour barrier in the kitchen - in fact no response to that part of my
enquiry at all.
All suggestions really welcomed: unfortunately I don't appear to qualify
for any grant-aid towards improved insulation.
many thanks in advance
Reply to
no spam here, thanks
use 150mm fibreglass instead of celotex, it's a fraction of the cost.
steel joist hangers - about £2 each, affix them in a straight line along opposing walls andfix your joists in these - but they don't need to be 150mm seeing as they will only be carrying the weight of a ceiling and not the roof or floors point to note here is that it's easier to affix one side only of the joist hanger, then insert the joist, then affix the other side of the hanger (they bend quite easily.)
Reply to
Phil L
On Fri, 21 Dec 2007 16:29:43 GMT, "Phil L" wrote:
Good idea! Thanks!
Also top tip! Except .. don't I need 150mm joists if I'm fitting 150mm fiberglass? I was meaning 150mm x 50mm (or 6x2 in old money).
I'm assuming the plasterer will need 50mm to aim his nails at, and I'll need 150mm for the fibreglass.
But that joist hanger suggestion is such a brilliant tip - makes the whole job immediately more practical, Thanks a bunch!
Reply to
no spam here, thanks
yes but you can use 4 X 2 and set them 50mm down from your existing ceiling.
Reply to
Phil L
On Fri, 21 Dec 2007 16:40:34 GMT, "Phil L" wrote:
!Flash! I love those blinding glimpses of the obvious: what a triffic bit of lateral thinking!
But not too bouncy in the middle of a 3.7m length? Well, !FLASH! A noggin in the middle.
Brilliant suggestions, thanks a bunch again.
Reply to
no spam here, thanks
Yes, and less of an irritant too - I have birds and a wife to think about (ahem - parrots). But cost is a consideration, so I'll have to balance the two when I choose the solution.
Thanks for the pointer.
Reply to
no spam here, thanks
What about an industrial grade suspended ceiling..pre finished, no plastering? the sort that goes in offices. Just add 150mm glass on top and the job is done.
Reply to
The Natural Philosopher
On Sat, 22 Dec 2007 01:15:27 +0000, The Natural Philosopher wrote:
My immediate thought is 'Yikes, that's an expensive solution!' Need it be? And is it a DIY job? OK for a kitchen? (I'll need to do some resarch on that). Ta for thoughts ...>
Reply to
no spam here, thanks
On Fri, 21 Dec 2007 23:00:04 -0000, "Steve Walker" wrote:
I had thought of that, but even the idea of getting the beads one-by-one into the end of the straw left me completly knackered, let alone actually blowing billions of the little bleeders into the cavity .... and catching them as they fly out of some previously undetected hole ...
Reply to
no spam here, thanks
No. Its a cheap one, because peopel who do that sort of thing do large spaces on low budgets. Its all screw together strip, preformed fiberboard panels and that's it.
And is it a DIY job? OK for a kitchen? (I'll need to do some
Have a look see. I've had it done in offices I have converted, some time ago. It was not as I recall that expensive.
Reply to
The Natural Philosopher
On 21 Dec, 16:06, "no spam here, thanks" wrote:
Dear msht I have done this on walls and ceilings (albeit sloping attic ones) What size and span are the existing roof joists? If ok then consider the merits of using TP10 or any equivalent p- urethane (preferably cheap seconds) slabs 8 x 4 I would go for 4" but 2" or 3" will do Here is the good bit - buy a pack of the stainless steel pins and large plastic pink washers that they use for putting this stuff up on external walls and pin or (if you are particulary worried screw) the slabs to the ceiling joists (which you will have to find and mark on the walls then ceilings) IF, additionally, you are able to glue with plasterboard adhesive (depends on existing ceiling surface) you will get better adhesion Then (at different centres) tack on plasterboard with the same fixings scrim the washers and Pink it (suggest you get a pro in for this?{ End product has no need for structural joist BUT and it is a BIG but you will need to check if the existing joist are man enough If not then existing suggestions best Chris
Reply to
Thanks for that: I was wondering about that approach. I think, tho, that if I want 150mm (6") insulation I might be asking a bit much trying to get fixings through the plasterboard, via 6" of insulation into a 2" target! More importantly, though, I'm not sure the joists are man enough for the job. 4" x 2" x 3.7m unsupported at 16" centres.
I think I'll wait and ask me man what he thinks when he comes in to do my other ceilings.
Thanks for the suggestion though least someone else thinks it's theoretically possible!
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