Sealed Inspection cover

[tiermat]

In our garage we have an inspection cover for the drains.

Due to us, and the next door neighbours, having washing machines that run into that drain we have a condensation issue in the garage.

I would like to replace the cover (which is currently a cast non-sealing type) with a sealing type one to cut down on the humid air entering the garage.

Do I need to replace the frame and the cover or can I just get a cover to replace the on in situ?

Also can anyone recommend a place for me to buy one from?

[mrcharly-YHT]

I think you'd need to replace the lot.

alternatively, lift the existing cover, put clingfilm all around the frame, then thick bead of silicon. Drop cover back on - the silicon will stick to the cover and make a seal, the clingfilm will prevent it from sticking to the frame. When the silicon cures, you can lift the cover and pull away the clingfilm.

[loadsabikes]

Alternatively, fill the frame groove with grease.

[tiermat]

Alternatively, fill the frame groove with grease.

Now that is just genius, and as the humid air shouldn't be under pressure it should work, and be much much cheaper than buying a new cover and frame then getting it installed.

[loadsabikes]

Not genius, time served plumber.

[tiermat]

<goes off to find big tub of grease>

[neilrj]

I would have thought the smell of sewage would have alerted you to the poor seal long before any damp did? Are you sure the damp is from the sewer?

[tiermat]

It's a grey rather than brown water sewer.

[neilrj]

Shouldn't be in surface water drainage, only allowed to discharge to a sewer - even if your town system eventually joins up (like most old towns do).

[tiermat]

I don't know about that, Neil, I just know that we appear to have 2 sewers, one for the waste from sinks/baths (and presumably rain water) and one for the stinky stuff.

Both washing machines empty into the former rather than the latter, and would appear to be the same the whole street along.  FWIW the houses were built in the 1930's.

[neilrj]

Nothing other than rainwater is allowed in surface water drains, and incidentally no rainwater should go into the foul drains either. It may be that you have 2 'drains' that both simply go into the main 'sewer' anyway (very common historically), meaning your rainwater is actually misdirected    I'd have thought a lid that leaks enough damp to be a problem would sound very noisy and smell soapy (or yeuky depending on plumbing).

[Tim Hall]

But I can't see where tiermat says rainwater sewers are involved.

His OP just says:

In our garage we have an inspection cover for the drains.

Due to us, and the next door neighbours, having washing machines that run into that drain we have a condensation issue in the garage.

[phil d]

I can see where Neil is coming from on this.  Is there anything else in the garage that could be responsible - tumble dryer, or is the machine a washer/dryer?

And Tim, in #9, Tiermat says "(and presumably rain water)"

[LittleWheelsandBig]

You shouldn't be running greywater into stormwater drains or rainwater into sewerage.

[Tim Hall]

I can see where Neil is coming from on this.  Is there anything else in the garage that could be responsible - tumble dryer, or is the machine a washer/dryer?

And Tim, in #9, Tiermat says "(and presumably rain water)"

Doh. (smacks self round head).

[tiermat]

FWIW the washer and dryer are in an adjacent building, not in the garage itself.

How do I know it's the drain? The smell of the cheap and nasty fabric softener that next door uses (we don't use it as both Mrs T and TLD have excema which is irritated by such things) and the occasional little brown Richard The Third I have found in there (next door have installed a WC in their utility room/shed).

Oh and the conversation regarding what should and shouldn't be going down that drain is one I have gone over many many times with next door, believe me.  This is the same neighbour who thinks it is ok to allow his garage downpipe to dump all it's water onto our land.  Hopefully the new neighbours (when we get some) will be more understanding of the situation.

[Quisling]

<goes off to find big tub of grease>

"man-hole grease" Fnarr fnarr.

</Beavis&Butthead>

[a lower gear]

Can't get to my Buildings Regs books at the mo' to check the proper name but any builders merchants will sell you an interior grade double sealed inspection cover. They come complete with frames and a rubber seal between the two. Fitting will necessitate removing exisiting cover and frame and chipping out rather deeper to accommodate the new frame. Depending on the type of new cover you may have to cast concrete into the hollow lid. If so, then consider adding extra reinforcing as they are usually inadequate. For belt and braces, add a sheet of galvanised steel at the base of the concrete. When I extended our kitchen over a sewer I installed a double sealed cover in the floor and carried the floor skim and vinyl tiles across it we've never had any smell or vapour issues, nor has the floor deteriorated in that spot. I just hope I never have to lift it, though I do have a stock of spare matching tiles against that evil possibility... 

Much simpler and infinately cheaper will be to seal between the existing frame and cover. Gunnable silicon sealant is probably cheaper than grease these days and will not tend to melt and flow in warm weather.

There remain enormous numbers of 'combined sewers' - i.e. mixed rainwater and foul (can be any or all of kitchen wastes, bathroom wastes, WC wastes). Our street of 1963 semis has a combined common sewer down the rear takingg kitchen, bathroom, WC and rainwater, and a common stormwater drain down the front taking rainwater only though a few houses have lead kitchen wastes into it over the years as extensions have proliferated. They CCS and the CSWD unite at the end of the street so it makes no difference in practical terms for sewage treatment which of the two a particular waste discharges into. In a previouss career I was a sewage works inspector: most designs of treatment works need neat sewage to be diluted considerably to operate. Most sewers require more water than is discharged by neat WC wastes alone to ensure there is sufficient flow to carry the solids along. With numerous additional discharges to sewers and storm water drains (e.g. drives, patios, concreted-over front gardens, extentsion roofs) compared to when originally installed, capacity is the main issue these days: best not to live at the bottom of a hill 'cos that's where the accidental overflows will occur