Reduce the ground level and damp issues

[Mr A]

Damp along the front wall and the party wall just behind the door.
Damp surveyor has recommended an "effective dpc" and the ground level be lowered to at least 150mm below the inside floor level or a stone filled soak away. Gas mains runs 10cm below the joist level. The joists sit in the masonry unprotected.


Would it be a okay to take up the flags to the right of the doorway carefully dig out around the gas pipe and fill with gravel to a lower ground level. Ive been looking at French drains but I have no idea of where or how to funnel the water as the reduced ground level will be lower than the drained footpath on the other side of the wall.



I was also wanting to get a couple of air bricks/vents installed in this wall. One for this ground level and a telescopic one for the basement in the room below.

I dont really want to get a dpc injected into the front stone wall. I have been thinking if i just get the damp plaster off the walls let them dry check the cavity isn't bridged with debris to allow penetrating damp. The added air brick ventilation along with the clearing of the cavity and as a last resort a dryrod dpc in the internal cavity wall.

What are your thoughts on my suggestions? Any better ideas?

 

[Doggit]

You need to use stones at least 1" diameter for a french drain rather than gravel. the gravel will fill with dust and dirt, and then you're bridging water across again. As long as you did down to bare earth, then any water will just drain into that. Injected DPCs are old hat, and I don't know how well they'd work in stone - if at all. A dryrod DPC, or silicone injection into the mortar is more common nowadays. You'll definitely need to take the plaster off and let the wall dry out, but I expect you'll find it's a solid brick wall, so you may need to batten the wall internally, and then use plasterboard - even though this wasn't the original design of the property. And that's the odd thing about the setup; was the gas main installed with the property, or afterwards, and how far out from the wall is it. If you expose the gas pipe whilst you're digging the french drain, then you need to find some way of supporting and protecting it.

 

[vinn]

Are you buying this property?

Is this road on a hillside or very low lying land? There are unusual features with the roadway, the kerb and the footpath.

Why not ask the neighbours how they had coped with what you have?

Do you know what a section view is - could you sketch one of the area in question from cellar floor to FFL?

 

[Mr A]

Yes I am buying this property. It looks as if the first houses don't have basement floors as you go further along the row the houses start to cut into the land and the houses start to have basement floor.

I am thinking the paint needs to be removed also I would like to install a cavity drain membrane and drainage to make this room habitable but I will tend to the more pressing issues first.

Thankyou for the advice it is very much appreciated.

 

[vinn]

Walk along the backs and you will see who has basements.
The house is on a slope, therefore you are fighting against the water table as it comes down the slope.
Your basement walls seem to be relatively damp free - some staining in a corner.
Membrane, pump & sump (draining to the rear) would be the way to go for any refurbishment.
Probe the joist tails with a small screwdriver - are they built in or are they sitting on a brick ledge?
I dont think that much useful could be done at the front - perhaps a couple of air bricks, & removal of the sand and cement fillet.

The interior damp plaster could be removed and rendered back in lime and sand. This will give you a say 20yr breathing space before damp salts appear again.

Nothing you show above would be a cause for concern - the house is what it is.

 

[Doggit]

Sorry to correct you vinn, but the water table is the height below ground that the water settles to over a wide area. I suspect you're trying to say that the water coming down the street when it rains is an issue, but any water that soaks into the ground, will just go vertically down, and as all of the houses seem t be cemented over at the front, there's not going to be much water penetration at all; this is more of a general wet ground problem.

The basement doesn't seem to be damp, so a pump shouldn't be necessary, but yes to the membrane if they want to use the basement as a room wouldn't do any harm.

Mr A, going back to the airbricks in your OP, as the rear of the basement backs onto the yard, do you have airbricks in this wall.

 

[Mr A]

On the other side of the staircase(rear of the Property) on the lower ground floor is the kitchen and it doesn't have air bricks built into the wall. It does have a vent sucking air out of the kitchen though and a vent that looks to line up with the combi boiler. It has one air brick at the top near the roof. Looks to be redundant drainage pipes and aweful paint make the house look abit of an eyesore.

 

[Doggit]

So the backdoor leads into the basement, and am I right in thinking it's fairly dry then. The combi boiler is getting it's fresh air from the outside, but you'll need fresh air in the place. Rather than airbricks, I'd suggest trickle vents on the tops of the windows

 

[Mr A]

The kitchen is drylined unsure of the method of tanking if it has even been tanked the damp/timber surveyor was unable to test as it would have meant a destructive test. The stairs run through the center of the house, to the eye the rear basement room(kitchen) looks fairly dry. But the earth retaining side of the house has some water ingress to the right hand party wall where mortars been forced out.

 

[Gerrydelasel]

Looks like Lancashire to me, right?

 

[Mr A]

You are correct Gerrydelasel it is Lancashire

 

[Doggit]

Is the party wall by the front door, or the other side. Picture please. I suspect you'll need to repoint, and then use a tanking slurry.

 

[vinn]

Wrong. User name Doggit. I'm sorry that, as in a number of your posts, you are wrong again.

The house is cut into the slope and into the water table.
A water table will roughly follow the contour of a slope.
Gravity moves water downhill.

Leave the air brick in the rear of the basement - its a basement, there's a chimney flue needs air, and dry lining in a basement might have been done as a method of dealing with damp.
Through ventilation from front to rear is also needed.

No tanking slurry is required - it will only move damp penetration upwards or sideways. Its often blown by water pressure.

 

[Doggit]

God, it shows how much out of date my Geography lessons are; I stand corrected on that point Vinn

 

[vinn]

User name Doggit, I made a number of points.