Having problems with damp on one wall of our Victorian semi. Chemical injection carried out in 2013 by Peter Cox still under guarantee. Only moved in 6 months ago and been quoted silly money for tanking the whole of the downstairs by a damp specialist. Could the patio be a potential issue, I have included photos. I assume if this is this issue, Peter Cox will not honour the failure of a damp course due to previous owners bridging with the patio!? Peter Cox want a call out charge of nearly £100 to even look at it. LP
I don't know where the DPC is. Do you?
It looks to me like the paving is incorrectly high, and needs to be taken up and the ground level lowered. It also looks like the paving is sloping towards the house, causing rainwater to run towards the wall. it also looks to me like you have a gully under the paving, which is most likely broken and leaking. It also looks to me like the wall has been repointed in sand and cement mortar by somebody using a teaspoon, or possibly their thumb, and this may well be because the original lime mortar had been softened and washed away by long term water.
A chemical injection will not cure any of the building defects that that I think I can see.
It looks to me like the paving is incorrectly high, and needs to be taken up and the ground level lowered. It also looks like the paving is sloping towards the house, causing rainwater to run towards the wall. it also looks to me like you have a gully under the paving, which is most likely broken and leaking. It also looks to me like the wall has been repointed in sand and cement mortar by somebody using a teaspoon, or possibly their thumb, and this may well be because the original lime mortar had been softened and washed away by long term water.
A chemical injection will not cure any of the building defects that that I think I can see.
You're right about the teaspoon. Looks like a child slopped it on. So would you recommend getting a general builder to lower the ground level and repoint in lime mortar and a drain specialist to check for broken or damaged drains in terms of the gully? In terms of who to approach. Only sign of a chemical DCP is a few holes in the course of bricks right up against the flags, so I imagine the original DCP a lot lower again!? Would we get away with a trench against the house rather than the hole thing coming up? or is it best to drop the whole area?
Yes, I guess so. I see what you mean so more likely the teaspoon/thumb mortar job...
there is an undesirable amount of green algae and black mould on the paving and wall.
I am always suspicious of old gullies on old houses. maybe yours is the one house in England where they aren't broken and leaking. That would be thrilling. If not, they'll need to be dug up and replaced, and that could reasonably be done at the same time as digging out the paving.
There is a good chance that when the house was built, it had a slate DPC which will still be present. You might be able to see it near a doorway. If you can find it, wire-brush the mortar joint to make it visible, and follow it along the house wall.
I can't see any airbricks. Does the house have solid concrete floors?
I am always suspicious of old gullies on old houses. maybe yours is the one house in England where they aren't broken and leaking. That would be thrilling. If not, they'll need to be dug up and replaced, and that could reasonably be done at the same time as digging out the paving.
There is a good chance that when the house was built, it had a slate DPC which will still be present. You might be able to see it near a doorway. If you can find it, wire-brush the mortar joint to make it visible, and follow it along the house wall.
I can't see any airbricks. Does the house have solid concrete floors?
tanking, like chemical injections, will not cure the building defects. It may hide them for a while.
I think it is solid floors, (?) laminate throughout and not lifted anything up yet to inspect. No sign of air bricks at the back of the house at all, some at the front but not sure if they are for the walls rather than the floors (photo) no access to the side of the property due to neighbours land adjoining so no view from there just yet until I get permission.
Attachments
Yes, this is what I want to avoid. I want to solve and not mask.
the projecting part of the wall looks like it might be a chimneybreast. These are often full of builders rubble, which will draw water up from the base much more than good clean brickwork. It may have no DPC, probably in the belief that an open flue and constant coalfire would keep it warm and dry. I think I can see efflorescence and old frost damage which may be related. Luckily, it can be fairly uncomplicated to open up a bricked-up fireplace and shovel out the rubble (preferably go down below floor level) and add an airbrick to ventilate the chimney and help it stay fairly dry. Drilling into the fireplace and prodding will indicate if there is damp rubble inside. A disused fireplace, opened up and ventilated, can make a useful wine store.
I would be very inclined to take up the paving, reduce the ground level, examine and probably replace the broken drains. That would reduce the excessive water load, and lowering the ground level will expose more bricks so they can lose water by evaporation, instead of soaking it up. Water rises into bricks until loss by evaporation equals water entering from below, though the mortar joints between bricks also inhibits capillarity due to change in pore size. If the drains are leaking and splashing they will add a lot of water to the ground against the wall, which would correspond to the wet area in that corner beside the gully.
if, as I suspect, there is an original slate DPC somewhere in that wall, lowering the ground level below it will make it much harder for the wall to be damp above it. look out for the floor also bridging it, though.
I would be very inclined to take up the paving, reduce the ground level, examine and probably replace the broken drains. That would reduce the excessive water load, and lowering the ground level will expose more bricks so they can lose water by evaporation, instead of soaking it up. Water rises into bricks until loss by evaporation equals water entering from below, though the mortar joints between bricks also inhibits capillarity due to change in pore size. If the drains are leaking and splashing they will add a lot of water to the ground against the wall, which would correspond to the wet area in that corner beside the gully.
if, as I suspect, there is an original slate DPC somewhere in that wall, lowering the ground level below it will make it much harder for the wall to be damp above it. look out for the floor also bridging it, though.