filling iregular holes

I have 2 irregularly shaped holes.
(stands back for funnies......)
One is in the ceiling where 3 redundant heating pipes go up into the void, presumable to header tank etc. The hole is about 6 inches at its widest, but irregular in shape. Pipes are still in place - wild horses won't drag me up there. How can I fill it? Plaster just drops out.
Second hole is where the skirting orta be, but pipes from combi enter it horizontally to disappear under the bath next door.
Would expanding foam be ok, since it is impossible to do anything neatly, owing to pipes, location etc. I assume it would not buckle the pipes, being able to expand outwards as well as widthways?
Both holes are in the cupboard which now surrounds the combi. Out of sight, but hate the thought of giant spiders making their home.........
TIA
ZD
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but
up
being
sight,
Go with the expanding, then we can all laugh at the tales you have to tell on how it took over the house. :-)) Only kidding !!!
The expanding foam is the best idea for this type of fill up job. Just remember to shake the can thoroughly before using it, and in between times before starting a new squirt. Go easy with it.
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On Sun, 12 Oct 2003 22:09:00 +0100, "Zipadee Doodar"
Stuff crumpled newspaper in, and plaster over that.
Expanding foam is ok too, but it can make a big mess. That half-full can of foam you shoved in the trash under the sink will begin to ooze and leak once you have forgotten it...
Thomas Prufer
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being
The trouble is that it will expand forwards out of the hole as well, so you'll either have to press it back while it's still soft, or cut it off when it's set. I reckon it would be less messy, and cheaper, to use plaster or even Polyfilla. You shoul;d be able to do it with a small knife or somesuch even with the pipes in the way.
Rob Graham
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Zipadee Doodar wrote:

Ahh, filler faom my favourite diy stuff! It should do the job nicely. Follow the instructions on the can. Even if it expands too much, mine always does, it can easily be sawn off when set with a flat woodsaw or large hacksaw blade. If you want the repair to lokk neater it can then be skimmed with polyfilla and it takes paint.
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Zipadee Doodar wrote:

Foam is good, yes.

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