MDPE & Expanding Foam

saw thread recently on expanding faom and thought this might be of interest.
I have a new Alkathene pipe (or MDPE to give factual type) bringing mains water into the build, this come sin via a PVC conduit.
The water board want the conduit filled with insulation - I asked about expanding foam - and they advised that under no circumstances muct expanding foam come into contact with MDPE pipe - it eats it away.
Anybody else come across this, I would like to follow up and see if true.
rick
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interest.
expanding
I've heard of the foam eating into plastics and things, but I've never read anywhere that it does. We use polyurethane guns to inject the foam into gaps and things, so I would have thought that if it did eat into plastics, they would sell you a plastic gun to use as the application method. I've never read on the instructions that is has any adverse effects on the things around it and it only says that it is flammable will still in the container, and that you should wear protective gear in case it gets in your eyes or on your skin. But that's just because of the propellant that's used to blow it out the tin.
Some foams are now resistive to UV in the sunlight and some are even being used as water repellents on or under other surfaces. All this stuff is on the tin when you look, so I would have thought the makers would have made anything about it ruining other materials more apparent in their guide on the containers.
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BigWallop wrote:

Hmmm - perhaps time to own up to a little DIY "mishap" shall we say ;-)
Some time ago we had a problem with, as it transpired, a mouse and a rat that had somehow got under the bathroom floor. Not sure how they go there, but they made a hell of a racket for a few weeks as we tried various ways of trapping / disposing of the blighters.
Anyway to cut a long story short, ratty decided to eat his way through the kitchen ceiling next to where the central heating pipes come up into the bathroom, and promptly found himself sat on top of one of the kitchen cupboards now unable to return "home". A phone call from SWMBO informed me of this, as I was on a clients site working late one evening. Having considered this method of escape a possibility, I had taken the precaution of placing a "humane" trap on top of said cupboard in advance. So said to SWMBO "does it look like he will go in the trap?". She replied "no.... he is BIGGER than the trap!". Anyway I asked her to keep him talking, and said that if he was there when I arrived home I would attend to the situation. Needless to say he was still sitting there when I got home. It looked like he was in a pretty poor state (having had nothing but mouse poison to eat for weeks!) and was not keen on moving. Needless to say I was not that keen on getting that close to him as he was a big bugger with long teeth! I decided the most expedient method of disposal was the addition of a small lead weight to the forehead... with the help of my trusty .22 air rifle! I hope ratties departure from this world was swift and painless - he certainly seemed co-operative enough by keeping perfectly still as I offered the barrel to his head! SWMBO was a little less impressed when he decided to bleed all over the top of the cupboard - but the up side is I was allowed to claim said cupboard as my own thereafter! ;-)
Mousy decided a few days later to escape from the tiled and boxed sections of the bathroom to go for a wee walk round the perimeter of the room as I lay there having a soak. He then made a small tactical error by climbing up the back of the pedestal bin and promptly falling in it instead of returning to his former hiding place. After my bath I decided that he and I would take a short walk to the woods where he could claim his freedom.
This then left the question of sealing up some of the small holes round the pipework to close off some possible entry and exit points. Expanding Poly Foam was (it seemed) the ideal solution. Did a fine job of the kitchen ceiling by the pipes. I then added some to where the pipes exit the boxed in section of the bathroom to go to the sink; since it looked like this was how mousy made his escape. Job done.
A few hours later I noticed that there were some traces of water on the kitchen tiles - much as if some water had been trickling down them from the ceiling level... seemed at bit odd. The only possible source was from the bathroom above. Went upstairs - it all looked ok - ran the taps - still ok. Flushed the loo.... oh dear (for want of a better expression!) a little cascade of water running down the kitchen wall with a slight disinfectant smell! Blurch!
A quick investigation with a torch and a mirror revealed that when the bathroom had been re-done (prior to our ownership) the loo must have been re-sited a couple of feet to the right. Hence its trap fed a pipe which had a right angle bend followed by a short run of pipe before turning the corner again to re-attach to the soil pipe in its original location - just under the sink in the boxed in section. These joints seemingly made water tight by the flexible soft plastic shroud that encased them and incorporated the rubber seals at the ends. The one under the sink now had a large lump of foam embedded in it where it had completely dissolved said shroud! Needless to say the shroud was no longer quite up to the job it was designed for, and the contents of the loo were being flushed into the ceiling void!
The plumber (I will DIY most plumbing jobs - but am not so keen on ones involving the output of toilets! - and anyway I had to deal with aformetioned client the next day) was amused!
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Cheers,

John.

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read
plastics,
I've
things
<snip entertaining tale>

For a while there I though the punchline was going to be that you sprayed ratty with expanding foam while he was on top of the cupboard. Oh well, still a fun tale.
Cheers Clive
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I thought the same - kitchen cupboard full of rat and bright yellow foam.

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Rick Hughes wrote:

I think I would have preferred that as well (in preference to kitchen full of effluent!)
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Cheers,

John.

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