[Closed] Using expanding foam around heating pipes

I've no idea about the foam, but if you do, I'd also be putting a layer of coarse wire wool in there too, because vermin.

yes but would mortar not be better?  Expanding foam degrades over time

I recently had a job cutting out a whole heap of expanding foam that the client had used to bodge up some drafty gaps. Despite being about 10 years old, it absolutely reeks of chemicals gassing off when you cut it apart. So if you are happy with the chemicals slowly leaching out into your house, crack on.

Personally I would use mortar and and bits of stone packed out, which is what I did for the client.

Why didn't your installer sort it?

Ours are mortarted in outside and inside, dose of expanding foam in between.

And if you have a condensate drain like ours outside (last three boilers were like this), then you need to insulate that with pipe lagging too as it freezes in the winter, stopping boiler from working. My current one even has external access hatch I can put hot water down as needed....

Aye, foam lag pipes and mortarif you can't get in to the deepest recesses a squirt of foam wouldn't hurt

Why didn’t your installer sort it?

100% this. What you've got there is an unfinished job.

Assuming the pipes are copper don't just put mortar in there as it will accelerate corrosion. We had a cowboy move a radiator for us a few years ago, he just threw some kind of mortar/plaster mix into the holes he'd made. About two years later the wall was soaked as the pipes had corroded and were leaking (a lot). A proper plumber came and sorted it and wrapped the pipes in some kind of protective tape before filling the holes.

Yep mortar will corrode the copper pipes

They should have sleeved them before passing through the wall, though I don't think its any reg unless it's gas pipe.

I'd use expanding foam. It's the do it all tool of the building trade. It will only degrade exposed to UV light.

I'd be using foam backer rod and flexible caulk at either end of the wall for a clean and finished look. Depending on how much space possibly using roxul (stone wool) to fill the void rather than a can of expanding foam.

Cheers all, will check it out in more detail over the weekend. And probably ring the installers on Monday. They've not been paid yet...

I had a gap in the ceiling where two copper pipes came through so I filled the gap with expanding foam.
A few years later I had a leak that was caused by the pipe corroding under the expanding foam.
No idea if the foam was the cause of the corrosion but I'd rather not do that again.

Others have beaten me to it. Your "more proper" is the installers completing the job you've paid them to do.

Or maybe, getting someone professional to complete the job and taking their fee out of the currently unpaid invoice.

Basically the same stuff that Grenfell was clad with, put it around pipework to create a firepath throughout your home, seems like a brilliant idea.

Buy soudal fire retardant expanding foam if you worried about the fire risk

Blue 20mm mdpe pipe cut it lengthways, slip it over the copper pipes

Go crazy with the crazy foam

Bit of builder silicone between the mdpe and copper to stop drafts, flying things, transformers etc getting in

they should have fitted a ducting into the boiler case. our external boiler cqame with a 4" duct which went into the hole in the wall and then into the boiler housing.
the boiler housing is well insulated and the hole in the wall for the duct was a very tight fit so no draughts at all.

Basically the same stuff that Grenfell was clad with, put it around pipework to create a firepath throughout your home, seems like a brilliant idea.

Apart from in this case not being flammable, not being a composite sheet material, not being built into something that's effectively a vertical chimney, and accidentally made a way for fire to spread between the flats.

And something designed to fill holes in fire walls.

Apart from that, they're the same.

On the corrosion point, how wet is it likely to be? I'd be worried if it was on an external wall getting rained on, less worried if it's in the garage. AIUI it's not the urethane foam that's corrosive, its water getting in along the pipes.

Short answer , yes use expanding foam.

Expanding foam does degrade with time when exposed to UV light / sun light. So should be OK inside a wall.
Expanding foam is not the best insulation, but better than stone or mortar.
Expanding foam will accommodate the expansion/ contraction of the pipes as the get hot and cold.

If the stone wall is a rubble stone type of wall there is the possibility of loose stones and rubble in the wall collapsing down onto the pipes and power cable. The foam can protect them.

Ideally the electric power cable and control cable would be in a type of plastic conduit.

Get some external pipe insulation.

The heating pipes and electrics to said boiler are going out of an, at a guess, 100m diameter hole 

No wonder it's drafty! I'd just brick it up, but if it's a nice view that side of the house maybe a few sets of French doors or something would be nice, should let plenty of light in

 

Basically the same stuff that Grenfell was clad with, put it around pipework to create a firepath throughout your home, seems like a brilliant idea.

"Basically" is that the basically that is defined as "nothing like" ?

twinw4ll
Free Member
Basically the same stuff that Grenfell was clad with, put it around pipework to create a firepath throughout your home, seems like a brilliant idea

Not really, 2 layers of the correct spec plasterboard will give you enough fire protection. I'd be worrying about the fire load from all the stuff that you have inside your home first TBH. Hopefully the cavity insulation isn't blown foam either....

Basically the same stuff that Grenfell was clad with, put it around pipework to create a firepath throughout your home, seems like a brilliant idea.

I've done a risk benefit, and considering the pipes are connected to a gas chamber, in a wooden cupboard, with wooden floor, filled with plastic coats, tents and camping gear including gas stoves, a metre from a fuel filled car and thought that a few cm of foam was the least of my concerns.

Thread update

I had a proper look this morning and we have a winner:

they should have fitted a ducting into the boiler case. our external boiler came with a 4″ duct which went into the hole in the wall and then into the boiler housing.
the boiler housing is well insulated and the hole in the wall for the duct was a very tight fit so no draughts at all.

There is indeed this ducting, all the pipes/electrics are going through it and they've expandy-foamed around it. However, it's not quite going into the boiler casing, there's about a 30/40mm gap, so the wind's getting up through the middle of it.

I rang the installers, they're coming out to sort it.

They'll be bridging that gap betwixt duct and boiler with gaffer tape before ye know it.

Aye, probably. As long as it sticks, I don't really care TBH. Gaffer tape is, after all, also known as duct tape.

Aye, probably. As long as it sticks, I don’t really care TBH. Gaffer tape is, after all, also known as duct tape.

It's not.

Gaffer tape is a product of the film industry (gaffer being the head of the lighting department), it should be heat and relatively* electrically resistant.

Duct tape is for sealing up holes in ducts. So it's main feature should be some degree of waterproofness.

The correct catch-all term for both is cloth tape.

*it's not PVC tape, and you shouldn't use it like that, but it shouldn't kill you if the light has an earth fault.

Well, there you go, EDIASD.

Duct tape is for sealing up holes in ducts. So it’s main feature should be some degree of waterproofness.

Ahem. I'm pretty sure DUCK tape was made for sealing ammo cases. Then gaffers and the like started using it for all manner of things.

Duct tape is typically an air tight aluminized foil tape used to seal HVAC duct work etc.
Duck/gaffer is not suitable for this mostly as the adhesive goes brittle and the tape essentially rots.