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External manhole odour

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Discuss External manhole odour in the UK Plumbers Forums area at Plumbers Forums

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PaulBr

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I have a square cast iron manhole cover in my garden that does not block the smell of toilets. It measures 655 x655 millimetres with a gap of between 5 and 6 millimetres all around between base and cover. The waterboard claim there is nothing they can do!! Is there anything I can use to make it airtight but also to be able to open it for inspection or repair? Apparently, the manufacturer of EVERBUILD THERMOFOAM AIRTIGHT ACOUSTIC EXPANDING FOAM EVTHERM7 that I originally enquired said that these foams are not suitable as they are not even waterproof. They said that probably I should be looking at closed cell foams. I wonder whether a foam of some sort blocking the surrounding gap might be better than a sheet of closed cell foam on which a heavy cast iron cover would be sitting? If a foam is suitable, will it be permanent, or will it allow access for inspection or repair with the possibility of reapplying the sealant? I read in earlier replies that silicone grease might be suitable but given that it is exposed to the sun almost the whole day, the silicone grease might last only for a few days?
Your help will be appreciated
 
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Plumbers mate open the lid put a sausage size all the way round in the lip and reinstall the lid
 
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IME, it's likely that the cause of the smell is a blockage somewhere in the drain.. A clear drain in good condition doesn't smell much, a wad of rotting toilet tissue, **** and wet wipes, OTOH, will absolutely honk! Even a partial blockage can cause the pressure in the drain to rise when someone flushes/empties a bath, which will pump the foul smell out through any gaps.

Who owns the manhole? If it's the water company you need to apply more pressure to them to fix the problem and check the drain is clear.
 
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Chuck said:
IME, it's likely that the cause of the smell is a blockage somewhere in the drain.. A clear drain in good condition doesn't smell much, a wad of rotting toilet tissue, **** and wet wipes, OTOH, will absolutely honk! Even a partial blockage can cause the pressure in the drain to rise when someone flushes/empties a bath, which will pump the foul smell out through any gaps.

Who owns the manhole? If it's the water company you need to apply more pressure to them to fix the problem and check the drain is clear.
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Absolutely right. It belongs to the water board, they checked for blockages, didn't find any, and after a lot of pressure they decided that the manhole cover is the the wrong one (lightweight for drainage that cover a number of other adjoining properties) and they will replace it with a heavy duty incorporating an internal plate! Thank you.
 
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I had a similar problem , a neighbour 3 doors away had a partially collapsed surface water drain .....which caused my surface water manhole to smell .
I simply put the very minimum of clear silicone between manhole cover and frame to seal the manhole .
* I stress it must be a small covering of the air gap .
When the neighbour had repaired their collapsed drain I just put a Stanley knife through the silicone ....to unseal the manhole cover .
Very easy & quick to do .....and easy to make non- permanent .
 

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Old man Jim said:
I had a similar problem , a neighbour 3 doors away had a partially collapsed surface water drain .....which caused my surface water manhole to smell .
I simply put the very minimum of clear silicone between manhole cover and frame to seal the manhole .
* I stress it must be a small covering of the air gap .
When the neighbour had repaired their collapsed drain I just put a Stanley knife through the silicone ....to unseal the manhole cover .
Very easy & quick to do .....and easy to make non- permanent .
Click to expand...
 

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