Drain replacement issue

[berty3000]

I had the old clay drains replaced down one side of my house and the company I hired used plastic ones to replace them. The drains carry rain water from the gutters into the combined sewer. The new plastic gullies each connect to a length of plastic pipe which link to the outlets (at property boundary) with a rubber fastener that has been tightened around what remained of the clay pipes within my boundary.

There's a bit of a long story behind this which also involved running a drain pipe from the front garden to the back garden to help with run off, and that drain runs down the same side of the house. It would've been preferable to leave the old clay roof drains as they were in my opinion, they appeared rock solid, but the company destroyed them and replaced with the new plastic ones. Anyway, that's water under the bridge, or down the drain...

What I noticed after the job was finished is that one of the new gullies is only one brick below DPC. The outlet at the boundary is set high, only just below the gravel board of the boundary fence which is part of the problem, nevertheless, the original clay one was two bricks below DPC using a P trap. The type of trap they've used to replace it is different so that the little grid the gutter drains to is now higher than was previously the case.

My concern is that this could be flagged on a future survey if I try to sell the house as being contrary to building regs. The proximity of the plastic pipe to the surface is also a concern, bearing in mind the old one was caked in concrete. The company put mortar over the top of it to give some protection and I have subsequently created a flag stone "bridge" so it doesn't get stood on. It is at narrow side of the house which isn't a main access, but this may also concern future buyers.

When I've tried to discuss with the company they've been dismissive and now won't communicate. Question to you wise men: does the work they've done look ok? Is this likely to cause me problems in future? What would you do, if anything?

I attach some photos.

 

[Ivor Windybottom]

I'd say it's better that it's higher than the shared pipe, as this reduces the chances of a blockage causing it to spew out of your drain. It's at the right height, surface level. It would look daft any higher, and would be buried in gravel if any lower.

I don't see an issue really - it looks like a fairly decent way of dealing with a difficult situation. It would be better if the pipe was deeper, but this height is dictated by the clay pipe pointing upwards.

As it's feeding into a combined sewer it needs the trap, which it has, it's a bottle gully. There should be a black plastic funnel inside the gully, this has the same function as an old-fashioned trap, of blocking smells, but with the advantage that you can pull it out and rod down the pipe if it gets blocked. This is a big improvement over the old style.

You could cut out the circular marked hole on the gully grid and extend the downpipe so it reaches inside it, this will eliminate any splashing as the water meets the grid. You could either replace the whole pipe with a longer one (not expensive), or add one or more couplers to it. There's usually a bit of jiggling involved in feeding it in, you'll need to remove a bracket or two and play about with it.

 

[berty3000]

Thanks for the feedback, Ivor.

I have built up the gravel in that area and put the flag stone bridge over the pipe - the gravel surface would be lower if the gully was lower down. The original ckay gully was two bricks below DPC, this new gully is only one brick below.

I agree with your points that the outlet is awkwardly high and it is good to have enough of a fall to it. My only concern is if a surveyor in future queries why the gully isn't two courses below DPC. Then they might be flagging up why are there flag stones there and is the drain vulnerable? The old clay one was encased in concrete. I'm not sure how well this plastic one will last with the way it is clasped on to the old clay pipe. Also, I think building regs notice might have been necessary for replacing the clay drain almost entirely, which could be a future headache, but company made no mention of this. Argh.

I like your idea about cutting the hole out of the grill, and then I could add one of those cheap couplers on the end of the downpipe. I currently have some roof rubber around it which I cut out and this works fine as well to prevent splashing.

 

[Ivor Windybottom]

Given where the clay pipe is, your setup is as compact as it could be possibly done, using that single socket angle shown. You couldn't improve on it without making major changes to the clay pipework. You really can't complain to whoever fitted it, they made the best of an awkward situation.

it couldn't have been cut back any further without crossing the boundary. Perhaps you could have got your neighbour's permission to dig up their garden, if you really think it's an issue then this would be the only way to get it lower. In which case you'd need to pay someone to do this as an entirely new project, I don't think it would be fair to ask whoever did it before to need to do you any favours, as they've done an OK job given the situation.

Here's a picture of one of my downpipes...

This is my own personal solution, I'm not a professional, more of a mad inventor.

Mine had an angled spout and was previously going all over the place including running down the gap between the hopper and wall, so I sealed it with the brown sealant. Sadly this isn't an option with your round one. But even after I did this, I found that it was overshooting the drain by firing towards the camera in the photo. My concrete surround is freestanding, the water can (and did) run under it.

So I did what you see above. It's actually the chopped off spout end plus 2 or 3 couplers. They make a sort of flexible extendable snake. It took a jiggle to assemble after removing the wall brackets but it works brilliantly, plus it has the advantage that it's almost silent in comparison to the racket it used to make. I've done the same with all of them.

The bottom coupler sits on the grid, it can't fall through it. There's some slack in them, they're basically funnels inside each other.

The two bricks below DPC thing is a sensible guideline, but it's never going to get your house condemned as unfit for human habitation. If it was sticky clay soil it may be an issue, hard paving could also be an issue due to splashing. But gravel isn't going to splash or hold moisture against the wall. My photo shows that this drain is 2 bricks below, but the ones at the other side of the house are only 1 brick below and no government official has demanded that I'm removed to safe accomodation!

 

[berty3000]

Haha, thanks Ivor! That's a great setup you've made, and all yours points understood and appreciated. My main gripe against the company is that the drain they replaced was 2 below dpc. This was achieved using a p trap design keeping the gully lower. I think this was difficult in this case though as the garden drain which runs from front to back of the house had to be cleared as well. I guess I'll just leave as is and hope for the best in future! I will probably cut the hole out of the grill and extend the downpipe into it for good measure. How would you cut the hole out? Plastic is quite thick in this case.

 

[cdbe]

Should have used a shallow trap

 

[Ivor Windybottom]

I see, I thought you were worried about the lack of depth in the pipe. That couldn't be improved, given the height of the clay pipe sticking up at an angle, without hacking it back into next-door's garden.

You could use a lower gully, but then it wouldn't be roddable so wouldn't be compliant. I'd suggest you've got the best all-round compromise given the situation.

If the water is actually going into the gully then you don't really have anything to worry about. I don't see any obvious hump in the gravel level in your photos, I'd say you're over-worrying.