Main downpipe on rear of house doesn't go into drain, expensive to fix?

t1redmonkey

Hoping someone can give some insight into this.  The main downpipe on the rear of a house I'm looking at buying just discharges water directly onto the ground.  Previous houses I've lived in have always had a drain under the spout of the downpipe so water goes in there when it rains.  The ground also does not slope away from the house, so the water just pools up against the walls instead of draining away anywhere, which seems to be causing some damp at the base of the interior walls.

Can anyone give an idea if it would be a difficult/expensive job to properly add in a drain for the downpipe to go into?  Wondering whether to proceed on the house or not, I don't really want to go ahead with it if it's a massively complicated job with lots of excavating etc.  Thanks!

Jonboy_1984

It involves digging but shouldn’t be complicated for a general builder, see here for a general guide:

https://www.drainagepipe.co.uk/soakaways-and-membranes/installing-plastic-soakaways/

casper_gutman

How old is the house? Our downpipe has been discharging onto paving and running off onto the lawn for a century, and isn't showing any sign of causing problems.

That's not to say that water pooling against the wall is acceptable, of course. Just that ponds and what are now called rain gardens have existed since before SUDS meant anything other than soapy lather!

Depending on the slope and surfacing of the area near the downpipe, there may be an easier solution.

The realistic worst case scenario is that you need a builder to put in a soakway as @Jonboy_1984says, and even that isn't such a big deal that I'd pass over an otherwise perfectly good house for it.

theoretica

Rainwater going to a soakaway is, where practical, preferred to sending perfectly good rainwater through the sewers for unnecessary water treatment.  Very standard - but does depend on how large the garden is and things like that!

t1redmonkey

Thanks both.  Does the soak away require heavy/large machinery to create?  Asking as the area the water discharges onto is concrete that is only about 3 feet wide (and then has steps to a upper level).

Bendy_House

That doesn't sound ideal!

This is a rainwater gutter downpipe? If there are no existing drains under the ground in that location, then you may need to divert the direction of this DP at higher level so that it does land on higher ground.

There's no grate in that section of concrete? Even without the DP, wouldn't rain just pool there?

Any chance of a photo? Do the sales partics show it, perhaps?

FreeBear

t1redmonkey said: Thanks both.  Does the soak away require heavy/large machinery to create?  Asking as the area the water discharges onto is concrete that is only about 3 feet wide (and then has steps to a upper level).

You could do all the digging by hand.... Hard work, but possible. But if you are paying someone, it is going to get expensive very quickly.

A mini/micro excavator can be hired for a day - There are models that will fit through a standard doorway - Depending on how high the area is behind the house, you might get the work done in a couple of days. I hired a mini-digger plus driver last year at £250 per day. Had plenty of time to dig out a soakaway and level/grade my drive.

Bendy_House

A soakaway will need to be positioned a min distance from the house - is it usually 5m? So, what is the garden like there? Would a soakaway location be close to neighbouring buildings?

Is there a drain anywhere along that side of the house?

And, just how much roof area is handled by that DP? Any more DPs on that side?

It would really help to have a pic - pretty much anything might help. Would you be happy to provide a Google view?

Mutton_Geoff

Probably best digging a soakaway by hand and maybe a couple of metres away from the house. If it's an older property, I'd be nervous about using a mechanical digger as it's much more likely to damage old clay pipes, water pipes,cables etc

Couple of people for a day, some rubble to clear, some materials and making good. I'd say £1,000 should cover it. Cheaper than damp brickwork.

t1redmonkey

Ok slight correction.  I phoned my surveyor to clarify, he's said there was a drain, but the issue is that the downpipe was on the left side of the rear door, but the drain was on the right side of the door.  So he reckoned the concrete (ideally) needs to be cut away at the foot of the wall and have a 'metal grill surface drain' put in that directs the water to the drain rather than pooling up at the bottom.  He said I could also just redo the guttering so the downpipe goes into the drain, but then I'd still have the issue of water pooling up around the rest of the wall.  He said he doesn't think it's a complicated job (But still sounds a bit tricky to me!).

I don't have a photo of the actual ground I'm talking about, but here's one from the back garden (you can see there are some steps that basically lead down to the single storey extension, that's where the issue is).

aoleks

you need a soakway, can be a DIY project. carefully dig a 1x1m box, place some creates in there and you're nearly done.

Soakaways: What are They & How to Build Them | DIY Doctor