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The roof flue pipe rubber boot lead flashing, do anyone know how is it to be fitted properly?

Got a builder to replaced the old leaking roof flue pipe rubber lead flashing, all the builder did is removed the roofing tiles around the flue, removed the old flue pipe rubber lead flashing, place the new one over the flue pipe, push the lead flashing down flat, no sealant.?

This was done over a year ago with no problems but a leak has started yesterday through the loft roof flue area as it rained very heavily.

Does it need to be sealed with roofing sealant or adhesive?

Hi kingkat,
There is no need for sealant, possibly a tile has moved or debris (eg moss) has built up on the skirt creating a dam.
You will need to get up and check.
Regards S

Had a roofer to have a look at the leak, repaired the felt area of the flue pipe with some new felt & baton.
After some heavy rain for most of the day, went up the loft to have a look at the flue pipe area, no rain water collected in the bucket.
Closer inspection with a torch, there’s a few beads of water, very minimal near where the rubber shoe is pulled over the flue pipe.
The roofer thinks it’s probably condensation, should be ok.
Maybe just seal it myself with roofing sealant, this could be easily done from the loft or just leave it alone
Any advice on this?

Hi kingkat,
Leave well alone, if you use roof sealant this may degrade the rubber collar.
Regards S

Hi Stoneboy
On some YouTube videos, you see tradesman doing repair/sealing roof vent rubber collar gaps with roofing caulk?
CT1 is what I had in mind.
There must be sealants out there that’s ok with rubber?

Thanks
Kingkat

Hi kingkat,
There are issues with a lot of sealants - many of them excrete acetic acid when curing. Nowhere in the CT1 technical spec does it list rubber as a material which can be joined. Suggest you speak to the technical departments of a couple of sealant manufacturers and see what they recommend.
Regards S