Windser Trap Inspection Chamber

[thebadger7]

Hi folks

We have this "windser trap" (I think it's called) at the edge of property boundary. Basically a big drain trap before it goes into main sewers.

It's 1m below ground, with an awkwardly positioned gas mains.

I'd like to avoid digging a great big hole every time it blocks - any ideas how I could build up some kind of inspection opening around it to ground levels?

Cheers

 

[a twig]

You could use inspection chamber risers?
Or just build up the existing brick wall to surface level?

 

[stuart45]

If it's blocking up I'd either replace the Winser trap, or what's normally done nowadays replace it with a straight pipe. They were used in Victorian times, but many are now damaged and cause issues. There's not much point in having one with a missing stopper anyway, as rats and gases will come through there. It's a bit more digging to do, but worth it.
When you rebuild it do it with engineering bricks in English bond. If it's over 5ft put in some step irons.

 

[thebadger7]

If it's blocking up I'd either replace the Winser trap, or what's normally done nowadays replace it with a straight pipe. They were used in Victorian times, but many are now damaged and cause issues. There's not much point in having one with a missing stopper anyway, as rats and gases will come through there. It's a bit more digging to do, but worth it.
When you rebuild it do it with engineering bricks in English bond. If it's over 5ft put in some step irons.

Thanks. If we replaced with a straight pipe, would you incorporate an inspection chamber? We also don't have a soil stack pipe/vent in our property, so wondered if we need the vent pipe in this set up

 

[thebadger7]

You could use inspection chamber risers?
Or just build up the existing brick wall to surface level?

The trouble is where the gas pipe is, if you extended existing brick wall it would run through it

 

[Flyfisher]

Yes, that gas pipe is a bit awkward. Is it the supply side of the gas meter or on the consumer side? if it's the consumer side it would be a fairly easy job for a gas fitter to divert it slightly. If it's on the supply side then it'll be a higher pressure pipe and only the utility company should touch it, in which case it's probably worth contacting them and ask if they could divert it slightly. It can't do any harm to ask.

Otherwise, my instinct would be to agree with Stuart45 and replace the trap so it never blocks again.

 

[stuart45]

Thanks. If we replaced with a straight pipe, would you incorporate an inspection chamber? We also don't have a soil stack pipe/vent in our property, so wondered if we need the vent pipe in this set up

Keep the inspection chamber, and the system needs venting, although you might find the mica flaps are seized up. The straight pipe is only a short length that replaces the Winser trap.

 

[thebadger7]

Thanks both. I'm leaning towards replacing the troublesome trap.
I spoke to a contractor who advised remove the trap. Use new plastic pipe with plastic inspection chamber (the smaller round ones) for future rodding access. So there's old clay joining to new plastic that's roddable, joining to old clay out the property. Sound sensible?
Not sure how that works with system being vented though.

 

[thebadger7]

Had a contractor over. Advice was to not remove, and build up inspection chamber around existing trap for access. As it's right by a retaining wall, so a lot of earth underpinning the wall would need to be excavated so could open up a can of worms

 

[stuart45]

Have you got a few more photos of the retaining wall and area around?

 

[thebadger7]

Yes here are a couple including one from road side
Got quoted £750 for building up a block surround over existing trap which seems steep

 

[thebadger7]

Thinking maybe could use something like this as a low cost/quick option to keep some access: https://www.drainagesuperstore.co.u...9C91s6GNQ2o3J2i_rFdga37We9ZKLdoBoC-34QAvD_BwE

Then if it keeps getting blocked haven't lost much money/effort to get it all replaced

 

[Stevers]

Should you end up keeping it. We have one of those traps (vented) and I use a 110mm Test Bung to close the rodding eye, as what I suspect was the original clay bung was incomplete:
https://www.screwfix.com/p/bailey-94-110mm-drain-test-plugs-2-pack/62513?ref=SFAppShare

Have to say that in 28 years the trap has never given me any trouble, and I like to think that it might just deter rats from exploring my drains.

 

[stuart45]

Seems a shame after you've done all that digging to at least not replace the trap with another, as they're still available. You wouldn't have that more more to go past the manhole. There must be an issue with the trap for it to keep blocking up, and will probably get worse in the future.

 

[thebadger7]

Seems a shame after you've done all that digging to at least not replace the trap with another, as they're still available. You wouldn't have that more more to go past the manhole. There must be an issue with the trap for it to keep blocking up, and will probably get worse in the future.

I do kind of agree - although we've been here 5 years and this was the first time it got partially blocked. A few mins jetting and it was unblocked, the issue was there wasn't any access.
I'm thinking if I use the plastic modular inspection chamber (like this: https://www.drainagesuperstore.co.u...9C91s6GNQ2o3J2i_rFdga37We9ZKLdoBoC-34QAvD_BwE) then can jet any blockages, and if we keep having issues in the future won't be much effort to take out and get full access again. Whereas building it up with bricks would be a right pain to dismantle should the need arise.

 

[stuart45]

Once in 5 years isn't so bad, so your idea seems a sound one.
One thing to bear in mind regarding the stopper, is that originally they had a chain fixed to the top of the manhole. If the manhole filled up, the stopper was easier to pull out and allow most of it to drain away.
It's quite rare to see one of these stoppers still in place.