Damp in wall, patio built too high outside - how to cure damp?

travel_freak

Hi,

More damp....!

This time in a kitchen wall.

Outside a patio has been built. This is a Victorian house, builders who I've had round told me that there is the original blue damp proof layer put in when the house was built. (This is right at base/ground level.) Above this, in the wall, is the modern injected damp proof course.

Prior owners built a patio against this bit of the wall. It is about 6 inches in height, so well above the original blue damp proofing and only a couple of inches below the injected one.

The survey said this wall is damp and it smells very damp in the kitchen.

I have lifted and removed a layer of patio and the rubble under it so that the wall can breathe again. Will this be sufficient to dry out the wall or will I have to do more works? Have new damp proof injected etc?

Also, one builder told me I could relay part of the patio stones I've removed provided I allow a 6 inch gap from the wall and put only gravel in that gap - please does anyone know if this is correct advice?

Many thanks for any advice.

Doozergirl

Yes, that would be correct advice. Make sure the gravel is also below your DPC as well, just in case. but
it will allow water to drain away from the area more quickly than soil and will look much better than a trench running around your house, which there still will be, just disguised by the gravel. You often see it on new builds.

The kitchen wall will need to dry out over quite some time but if there is no way for the damp to access above the DPC anymore than it won't do any more damage. The DPC is useless if it's being breached and will do it's job again when it isn't.

ariba10

travel_freak wrote: »

Hi,

More damp....!


Also, one builder told me I could relay part of the patio stones I've removed provided I allow a 6 inch gap from the wall and put only gravel in that gap - please does anyone know if this is correct advice?

Many thanks for any advice.

I would leave a gap but leave out the gravel unless you think it would be too dangerous to do so.

Six inches is enough as long as it goes down well below the damp course.

alan292

hi travel freak....i have encountered this many times in my working carreer....you have done the right thing removing the patio ,and replacing it with one leaving a gap is the correct method to adopt,but i would advise leaving the area affected by water ingress until it has completely dried out before backfilling the gap with rubble.....also inside the house you may find the plaster requires to be stripped back and the wall allowed to dry properly aswell.....

travel_freak

Hi,

many thanks for the helpful replies.

Please can I just check I haven't misunderstood - easy for me!!

At the moment there is a trench between the damp kitchen wall and the rest of the patio.

Ideally I would like to leave the rest of the patio where it is as it looks nice and will be a hell of a job if I have to lift and lower it all.

So at present the depth/height of the trench is about 6 inches and it is also about 6 inches in total width, measuring from side of wall out to where patio starts again.

It looks dreadful so I'd definitely have to fill it in again eventually.

Have I correctly understood that I don't need to add earth but just gravel, on its own, something like pea shingle?

Sorry to ask so many questions but I want to get this right before my kitchen goes in on aforementioned wall!!

Have now taken out the units along that wall and the plaster does not look good, also there are just bare bricks showing inside at the bottom near the floor level with what look like the holes made outside for the DPC - confused?! Shouldn't this have been fully plastered inside?

Please does anyone know how long I'll need to leave it to dry out as the kitchen is a depressing disaster zone at the moment and I'd really like to get new one in asap? How will I know whether it's dry enough - should I get one of those damp meters and just keep testing it from time to time?

Huge thanks for any tips as I'm totally in the dark here...!

ariba10

As long as there is a gap between the building and the Patio and the gap extends down below the damp course it should be O K. (6 inches below the damp course would be perfect.)

The wall will take some time to dry out but with summer coming, that should help.

Canucklehead

Good evening: We had a similar problem with a previous home (3 bed Victorian stone) ...this site has lots of great advice for period property owners. We used the french drain method to deal with the damp.

HTH

Canucklehead

travel_freak

Hello again,

Update on my damp problems... Having lifted the patio the wall is trying its best to dry out. I've borrowed a dehumidifier and that is drawing out tons of water.

The plaster on the inside of the wall looks very strange, a sort of pink/brown colour and I wonder if it is also the wrong type of plaster. Even if not, would it be a good idea to hack/chip this off to get back to bare brick - I just thought this might help the wall to dry out quicker, but not sure?

I guess it wouldn't do any harm?!

Any advice gratefully received.

Many thanks.