How to seal large holes in bathroom ceiling for boiler flue and pipes

grassylawn

My boiler is in a cupboard in my bathroom. I noticed that there are gaps around the pipes and flue in the ceiling, as per the photo. [The metal bar in front of the flue was just something I dropped down from the attic to confirm that the holes were going right through.]

There is a lot of condensation in my attic. I want to seal the gaps around the pipes and the flue to stop water vaour from the bathroom going up there.

[The condensation is all on one side and I am reasonably sure there is insulation pushed into the eaves, so I will remove that as well, but I think the holes in the bathroom should be addressed as well.]

It is very difficult to access the holes from the bathroom. I can access them from the attic more easily (just pull up a loft board).

What would be a suitable way of sealing the gaps? Is there anything I need to watch out for? Would it make sense to turn off the gas to the house in case I somehow damage the gas pipe when I remove the loft board?

My best idea at the moment is to just use a load of duct tape. Seems like a safe option at least in the sense that I'm not giong to **** anything up in the process.



Or that reflective tape you use to out insulation on pipes? I might see if I can reach thr back of the hole with a ladder or something and stick that in from the bottom if I can. (Cupboard is in the corner beside the toilet so it is very awkward yo reach from thr bottom like i said...

I suppose the flue and pipes will be hot. I suppose that silver insulation tape is ok to use around hot things. So I suppose that is a safer option than duct tape? Or is duct tape fine anyway?

jimf

you could use heat resistant expanding foam i presume and trim back tidy when cured

grassylawn

jimf wrote: »

you could use heat resistant expanding foam i presume and trim back tidy when cured

Thanks for the suggestion. I avoid foam because apparently it off-gasses formaldehyde for years. I have a two year old who had respiratory issues so I try to keep the indoor air as good as possible.

upupup

I would put a sand cement mix on top of the duct tape(from above in the attic).If its not solid,its very easy for mice to invade your house

grassylawn

upupup wrote: »

I would put a sand cement mix on top of the duct tape(from above in the attic).If its not solid,its very easy for mice to invade your house

Thanks for the suggestion. I think we're safe from mice entering through the attic though? We live in a detached bungalow with eaves that overhang a good foot from the wall. It's block-built with external wall insulation - so I don't think they'd come up through the walls either (and if they do they'll probably find a more direct route than going through the attic).

grassylawn

Went ahead with a combination of duct tape and silver tape, done from above. Could feel the warmth coming up through the holes while I did it. Seems grand. Will put a bit of loft roll type insulation down on top of it.

sheff the ref

Remember one thing, if it is that cold, there is a possibility of Water Pipes/Tank freezing in the type of sub zero temperatures we have had this week. Any degree of warmth that escapes up as you have shown, prevents freezing.

I have had a manhole open all week to let warm air up from the bathroom and keep the tank and pipes from freezing

Lessons learned from the hard freeze during Christmas 2010

grassylawn

Yeah I have insulation on the pipes and a jacket on the tank, and no insulation under the tank... Though I noticed the pipes to the shower are uninsulated actually, but there is a gap in the insulation beneath them so one issue mitigated the other I guess.