40mm into soil pipe - need a trap?

[bsr]

Practically speaking you could change the elbow coming out of the wall for a Tee and then connect the rainwater into the top of it.

Regs wise, I believe that even in a combined system the rainwater and soil should be separate until they reach the sewer. Otherwise if there is heavy rain or leaf fall from the rainwater then you risk the pipe clogging and the rainwater coming out of the toilet...

So I wouldn't do it.

 

[Madrab]

The vent is inside the lean-to out building and the sewer manhole is on the other side of the lean-to building.

When you say the vent? I can't see an external soil pipe coming out of that extension roof, so what/where is the vent? That and where does that soil pipe go inside the lean-to, does it just head down, into the ground then out to the chamber? I presume that's the WC soil pipe?

 

[Hugh Jaleak]

One of the risks you run if you attempt to connect the rainwater to the soil as per your proposal, is you'll be venting the sewer through the downpipe and out at the gutter outlet. There is then the possibility you'll get foul air going under the eaves, and into the space behind, which given the dormer affair you have, then into the room(s) beyond.

 

[Ivor Windybottom]

Practically speaking you could change the elbow coming out of the wall for a Tee and then connect the rainwater into the top of it.

Regs wise, I believe that even in a combined system the rainwater and soil should be separate until they reach the sewer. Otherwise if there is heavy rain or leaf fall from the rainwater then you risk the pipe clogging and the rainwater coming out of the toilet...

So I wouldn't do it.

There are many more reasons not to do it, all previously stated.

 

[Ivor Windybottom]

I replaced every underground sewage and rainwater pipe for our house. It's not actually very difficult, definitely not worth £30k. It can all be done by one reasonably healthy person, you shouldn't need a digger unless it's very deep.

 

[cdbe]

The solution is a trapped gully fixed to the wall, cut the legs off first and fit a little basket to collect any leaves.

Spend the other £29,990 on a cruise.

 

[Ivor Windybottom]

Extremely unconventional, but technically it would work!

You'd need some good brackets, there would be a kg or five of water in that trap at all times.

It would be infinitely better to do it properly.

 

[Hugh Jaleak]

Extremely unconventional, but technically it would work!

Until it freezes....

 

[Ivor Windybottom]

A very good point.

Also it would look bloody stupid, and would scream at the world that the homeowner is a botcher.