High ground along exterior wall, opinions on drainage most welcome...

[DW Brown]

Good morning all,


My partner and I recently moved into our house in Falmouth. This is our first post, but I have a feeling we will be seeking advice on tonnes of issues and ideas we have over many years to come. Eventually we would like to strip it back to its former glory, but that is a long way away. To start, though, it's drainage.

The house is mid 19th century, stone walls, has been rendered externally to external ground level, no damp course or external tanking, membrane etc.

We have a path between the side of the house and a retaining wall. The path was concrete, but at some stage was excavated to run services - definitely water, maybe gas - and backfilled with dirt.

I have had a look at digging some of it out along the line where the concrete was cut when these were installed, which runs more or less parallel to the base of the wall of the house, between 100 and 250mm from it.

At one end, I can get a decent way below the level of the internal floor, at the other end I'm not so sure.

My plan was to dig this trench out as much as I can below the level of the internal floor, and lay a perforated pipe/french drain, chippings, membrane to stop it clogging etc. to flow into the existing drains in the ground at the rear of the house.

What do you think? Is this a terrible approach? Should I cut away the concrete along the wall or try to remove the material below it? And how about an additional ACO drain for surface water while I'm at it?

Thank you in advance for any assistance and advice, it's much appreciated.

D&A

 

[mh12]

Welcome to the forum. You'll have a swell of a time here and learn lots.
In one word ZebColm trenches named after 2 of our experienced members on this forum.
They'll be along to give description but you might want to google the term . When I last looked there was some information about it although I have no direct knowledge and therefore I will leave the rest for more experience members.
I

 

[DW Brown]

Thanks very much for your response. I've had a good look into the ZebColm trench, and I picked up on something Malcolm (I think) has written elsewhere on the topic...having continued on our dig, we have yet to see water pooling anywhere in the trench, which is a plus.

However, I just went to see if I could grind away the concrete return/ledge (remnants of the path) at ground level along the house and discovered (almost destroyed) a lead water supply pipe running under it. This complicates things somewhat. Without rerunning the supply (also supplies three neighbours) I don't think it's an option to clear material away and have an open trench alongside a la ZebColm.

Is it worth cracking on with a french drain if there doesn't seem to be ground water filling the trench? Would it be worth paving the path with an ACO?

Thanks.

 

[a twig]

Depending on your utility supply they may come and replace your lead pipe for free, at which point you can get it slightly re-routed to suit.

A zebcolm trench doesn’t have to be continuous so if the above isn’t an option then that particular section could be left filled in to protect the pipe.

We had an external door so rather than over complicate things our trench ran either side of it and I just left the ground in front of the door untouched to preserve access. Still achieved the end goal of a dry interior

 

[DW Brown]

I've called SW Water to see what they think, but they have no maps and will get back to me.

I imagine it runs the length, and at a similar depth, so I think it's a no go unless it is re-run away from the wall. I'm pretty excited about the prospect of them finishing off my trench for me...

It's also possible it could be a gas pipe (according to someone at work). I'm an electrician and I'm on sites all day every day - it's astonishing how little I have picked up from other trades. My fault entirely, but I will look to rectify this now I own rather than rent. Time to start asking more questions there as well as here...

 

[DW Brown]

They have nothing on their map, I should say. The DO have a map. Or many maps.

 

[Flyfisher]

This website may help with buried services, though it's not definitive: https://lsbud.co.uk/

I've used it in the past and found it to be partially useful in that it identified some buried services, though it didn't reveal the mains water supply to the house, unlike Flyfisher junior who managed to find it with a mini-digger with inevitable results . . . but that's another story!