Insulation difficult

[meow2222]

There's a small space near the cooker thats peculiarly inaccessible. The on= ly way to get anywhere near the ceiling there is to lie on one's back, any = other position is simply not doable due to the combination of not practical= ly movable obtacles. The small ceiling area needs insulating, the big quest= ion is with what. It must perform well in a fire, basic canned foam is no u= se.

Probably the only physically possible way to do it is to spray or flick som= e sort of sticky insulation up there. The question then is what, as I don't= have a tyrolean applying thing. That leaves:

1 fire rated foam - how does it behave in a fire? 2 papercrete - what would make it sticky enough to be flicked up onto the c= eiling? 3 wet cellulose? Where's best to buy it?

The other perhaps is to use sticks to get bits of something up there, but i= t wont be possible to measure up there, so probably that means tufts of fib= reglass after spraying with glue, or something similar. What type of glue, = given that pva has no grab?=20

With any chosen insulation, how to apply a VB? It will be needed, given the= level of damp when cooking.

NT

[Tim Watts]

On Thursday 24 January 2013 01:25 [e-mail] wrote in uk.d-i-y:

Pictures?

[Huge]

[20 lines snipped]

I would have thought pictures would have had too small a "U" value.

(Sorry.)

[John Rumm]

Having a bit of difficulty visualising exactly what you are doing...

What is above the ceiling?

Would a PIR foam backed plasterboard work?

[meow2222]

Above the half inch ceiling is fresh cold outdoor air.

Not at all. No ability to reach up there to measure, no ability to get it up there into position. Hence I'm asking about the sprayables.

NT

[RobertL]

fire rated expanding foam?

A versatile and easy-to-use fire-rated expanding foam

BI Fire Classification Excellent thermal insulation Tested to BS476 Part 20 750ml Cannister with applicator nozzle

[John Rumm]

Would you need to measure if you cut a bit only big enough to fill the space that's difficult to reach - spray the back with low expansing board fix foam and prop it in place until set.

Alternatively, can you attack the problem from the other side - if there is only the sky in the way?

[Tim Watts]

On Thursday 24 January 2013 13:42 [e-mail] wrote in uk.d-i-y:

Can't you close it off lower down with some insulation board and plasterboard if it is such an awkward space?

[polygonum]

So is obviously aware. But how does it perform?

[meow2222]

You must have something in mind, how do you propose I determine the size & = shape of PIR board to cut without being able to get up there? Its not the s= implest of shapes.

You know I might just have an answer to that. 2 sticks of wood joined at on= e end with a bolt. Loosen bolt, spread sticks to fit, tighten bolt, take do= wn & measure.

No, its an essential ventilation path, one that cant be moved without an in= ordinate amount of work. Very close to it is steelwork, and the access on t= he other side is so poor that getting anything behind the steel just isn't = doable. Its all a rather flawed design. I've done what I can on the outer s= ide, but that's limited. I can insulate most of the interior piecemeal, fit= ting it around the fitted kitchen, but the last section behind the built in= cooker is one tricky customer. I cant improve access any by moving the coo= ker.

I did manage to answer one question, how to put a VB onto sprayed insulatio= n: aluminium flake paint, long brush, face mask etc.

NT

[meow2222]

Its possible, yes, but it would then be twice as much work, and the access not a great deal better.

NT

[meow2222]

Its above a cooker, so would need to not produce toxic fumes in a fire. If = it also works as a fire barrier that would be a real plus. I don't know the= fire performance of fire rated canned foam, but I presume in the end its p= lastic, so would burn away fairly quickly in a food fire creating toxic fum= es. Usually fireproofed plastics only really self extinguish when there's n= o external heat source, nothing better than that.

NT

[John Rumm]

Well I have not seen a photo - but I was assuming this was a difficult to get at corner. In which case a bit of board with a corner on it would fit.

Yup if its a non right angle... a carpenter's bevel would do the same.

any gloss paint would probably do the same...

[stuart noble]

Would have helped

[meow2222]

I've only ever seen little 6" ones

NT wrote:

I guess no-one knows, I'll have to do more searching.

NT

[meow2222]

f it also works as a fire barrier that would be a real plus. I don't know t= he fire performance of fire rated canned foam, but I presume in the end its= plastic, so would burn away fairly quickly in a food fire creating toxic f= umes. Usually fireproofed plastics only really self extinguish when there's= no external heat source, nothing better than that.

I got a picture when there today. The battery ran out so only got one, and = its not the best.

short, doing it with sheet insulation would need a minimum of 9 pieces i= n an area where most would be out of reach.

NT

[Tim Watts]

On Friday 25 January 2013 16:27 [e-mail] wrote in uk.d-i-y:

OK - that does help and yes, it looks awkward.

Are you able to reach up and touch that plasterboard?

If so, I would fashion a piece of celotex into about the correct shape - if you can place it with one hand, then liberally coat it with Stixall/Pinkgrip/etc and shove it in.

Repeat with a prepainted bit of plasterboard on top for fire resistance.

Add a bit of fire PU foam round the edges to get the final seal.

Is that viable?

[John Rumm]

It looks like this space is enclosed voided off section of ceiling, is that correct?

(not obvious from your original description).

If the assumption is correct, does that mean the insulation won't be visible from the room?

If its enclosed, then one of the two part spray foams designed for doing the underside of roofs etc might be the kind of thing you need.

[meow2222]

If I could reach up there it'd be a doddle. As I cant, I can't use sheet.

When I say can't, I really do mean can't. Due to an unfortunate combination of design factors it just isn't an option.

NT

[meow2222]

Its not enclosed, but not visible, so sprayables are an option.

Directly above a gas hob on that ceiling... no. Cellulose performs well in fire.

NT