Odour from internal manhole cover - how to seal?

Boothus · Nov 30, 2020

Hi,
I've an internal manhole cover in my garage, covering the main waste drains. Only moved into the house about 6 weeks ago but noticed it occasionally smells a bit cabbagey around the area of the cover.
Have lifted, checked for blockage and cleaned out somewhat but still get a bit of smell now and then. Looking at the cover, it looks like the seal might be past its best, so I was thinking of applying a good layer of manhole grease around the edges but wanted to see if anyone had any better suggestions?
Thanks,
Ben

rpm · Nov 30, 2020

Wash both surfaces and applying grease is a good way simple way to start with.

Boothus · Nov 30, 2020

Thanks RPM, do I need manhole grease or could I use some alternative from Screwfix etc. that's available in a smaller quantity? (ideally don't want to spend £35 on a 3kg tub of grease)

rpm · Nov 30, 2020

Boothus said:
Thanks RPM, do I need manhole grease or could I use some alternative from Screwfix etc. that's available in a smaller quantity? (ideally don't want to spend £35 on a 3kg tub of grease)

Well, going by another post on the same subject somewhere else recently a respected poster said even Vaseline would do, of course any nicks in the seal and it wont seal properly.

Ben-gee · Nov 30, 2020

Could try a close cell rubber seal, like EDPM for draught sealing

Boothus · Nov 30, 2020

@rpm when you say any nicks in the seal, do you mean the rubber seal in place or the seal I'd create with the grease?

@Ben-gee do you mean tear out the existing rubber seal and replace with EPDM?

Thanks

rpm · Nov 30, 2020

Boothus said:
@rpm when you say any nicks in the seal, do you mean the rubber seal in place or the seal I'd create with the grease?

Grease needs something to adhere to applying large dollops will bridge gaps but could drop in over time.

Boothus · Nov 30, 2020

Understood. I might remove the old rubber seal and replace with something similar before applying grease. At the moment, the old seal has gaps in it. This might be a dumb question but does it matter what shape the seal is, as long as it fits into the groves? E.g. this Stormguard EPDM Rubber P Strip White 20m - https://www.NoLinkingToThis/p/stormguard-epdm-rubber-p-strip-white-20m/33145#product_additional_details_container looks different from the seal that's currently in there but not sure if I can find an exact like for like

Timmy D · Dec 1, 2020

Don’t finger paint/be too careful, load it all up with grease, it’ll be fine.

Boothus · Dec 4, 2020

Gave it all a good clean and sprayed down with some industrial deodoriser. Gave it a thick layer of silicone grease and has been stink-free for 48h.
Thanks for your help

Luke smith · Jun 5, 2023

Hi Boothus,
Could you give me an update? Still fine? I have a very similar problem.
I wonder if you could add the name of the silicone grease you used.
Thanks

Lou · Apr 12, 2024

(Just bumping a few older threads, they will drop off what is new soon)

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Odour from internal manhole cover - how to seal?

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