Fixing bay window concrete surround

[CH_AD]

We have concrete surrounding our bay window. I assume this was not an original feature and was put there to move water away from the house.

As you can see it's seen better days. The part that is missing is from work we had done to replace a lead water pipe last year which goes into the cellar.

The cellar gets damp but I'm aware these were never designed to be dry places. It gets very damp in the corner since the water pipe work, hence the tarp I've had over the missing part for a year. There is no damp in the house.

I want to fix this myself as easily and quickly and cheaply as possible - I don't really want to remove the remaining concrete and open a can of worms, I also don't fancy concreting the missing part.

The desired outcome is to just move water away from the house, in the same way the current concrete is assumedly doing.

I've decided the easiest fix would be to patch up the existing cracked concrete with cement, put down a damp proof membrane on the exposed brick underneath the plinth and run it at and angle away from the house. I'd then fill that space with stones/gravel and then cover this and the existing concrete with some decorative aggregate.

The question is, if this sounds like a sane plan, is do I need a breathable membrane, or can I just use some cheap stuff like this?

 

[CH_AD]

Part of the bay window concrete surround is missing due to some water works, and rather than remove the whole thing and re-do, or concrete the missing part, I plan to:

• Create a sloped surface with rocks (see photo)
• Apply a damp proof membrane over this and fix to wall with double sided butyl tape (see photo, this isn't complete, just placed it down to get an idea, I'll be buying more)
• Patch up cracks in the surviving concrete
• Fill this space with gravel, and then cover this, and the remaining concrete with pebbles (see diagram)
• Add border between new pebbles and soil.

No damp in the house, but cellar gets even more wet since all this. It's just to reduce damp down there, and not have water going straight down the house.

Could any problems arise from this, or is this overkill? Or good to go?

I'm aware the DPM is not breathable or anything, but it's only a small area, and brickwork in the cellar is exposed so moisture can escape if needed... i assume (i don't know what I'm on about).

 

[Wayners]

Running a aco drain around edge?

 

[CH_AD]

Running a aco drain around edge?

Wasn't planning on. Just wanted to divert rain water away from the house.

 

[Wayners]

You have a drain outlet. Consider aco

 

[CH_AD]

I did think about a french drain at one point, but is it really neccessery for this small area? It might be worth noting that this part has been covered only with some tarp for the past year and it's not been an issue. I just want to move rainfall down into the garden area, and cover the area with pebbles.

 

[JohnD]

What you suggest is not wrong, but I see you have a hundred year old house, with a glazed clay drain in the ground, and damp near it. The mortar between the bricks is eroded, this is typical of lime mortar soaked by a long term leak.

The clay drain is pretty sure to he cracked, broken and leaking, and your source of damp. It will make the cellar damp. Excavate it to find the break, and renew it in plastic with a new gulley.

You can hose the mud and eroded lime out of the joints and repoint them. It is OK to use cement mortar below ground, as this part of the wall is not "breathing" (losing water by evaporation)

The thick plinth will also prevent evaporation, it might have been added in attempt to hide damp (it does not cure it, it makes it worse). Do you think it is original to the house? What I can see of the brickwork looks nice quality.

 

[CH_AD]

Cheers, I think the plinth is original - all of the terraces around here have them. Some have exposed brick between the plinth and the stone cill.

I don't fancy opening a can of worms with the drain and repointing brickwork, hence my quick plan to protect with membrane and forget about it.

If I see any cracks in the drain, could I patch up with cement? I have some cementone rapid setting stuff to hand.

 

[CH_AD]

Also if you see an older post of mine regarding the water pipe, it was very badly fitted - not sealed properly or anything which is probably why the damp is worse.

 

[JohnD]

I don't fancy opening a can of worms with the drain...

Mending a broken and leaking drain is not exactly opening a can of worms.

It is a remarkably simple job, if you can use a spade, and very common on older houses.

Covering it up will not mend it.

When you replace a broken drain, it is usual to find multiple old attempts to patch it up with mortar poultices. None of them work.

 

[CH_AD]

a can of worms.

You don't know me

 

[JohnD]

If you ever dig out a foul drain (not rainwater) you will find lots of wriggly red worms feasting on decaying organic matter.

 

[Ivor Windybottom]

You can't get one-way polythene. It's as likely to keep water in as keep it out.

You should improve/repair drainage rather than putting barriers in.

 

[CH_AD]

Pi

You can't get one-way polythene. It's as likely to keep water in as keep it out.

You should improve/repair drainage rather than putting barriers in.

Wouldn't any groundwater just hit the DPC/go into the cellar as usual? Which is fine. I just want to limit surface/rainwater at the edge of the house, that is all.

Basically my thinking is emulating the function of the existing concrete surround by adding gravel against the wall with a DPM sloped away for drainage. The membrane would only be attached around the top and underneath the plinth. See diagram.

 

[Ivor Windybottom]

It all makes logical sense until you consider the water that's behind it. Then you've created a problem that wasn't there before.

There's a reason that most people don't do what you're doing!