Party Wall Rising Damp

[slimj]

I have a lot of efflorescence on a party wall in my kitchen and I could do with some advice on how best to proceed with it.

The property is a terrace and there is a ‘step up’ between my property and the adjoining owner.

I am sure that given the efflorescence the party has damp as it has no damp course.

The floor is solid and when I broke away some of the damp timber flooring/skirting, what appears to the DPM is present – and clearly not tied into the party pall.

My first thought was to strip the wall, install a chemical DPC and then render the wall again with a sand and cement render (incorporating a salt inhibitor/waterproofer). Also being careful not to bridge the new DPC at low level.

My concern with this is my neighbour and that their property and internal floor level is higher. If the DPC is not injected right though, or even if it is, damp can track around it.

Yellow line is the DPM, grey line indicated the slabs (though neighbours position is unknown) and red dots are chemical DPC.

Any help would be appreciated.

Thanks.

 

[ree]

You have a solid floor with a DPM that doesn't lap up behind the skirting, and there is what looks like efflorescence on the wall above. Your neighbour's solid floor is higher than your FFL.

The wood flooring laid over your concrete floor, & the skirting, is rotting with fungal damage.

Is the front floor(s), beyond the kitchen, solid or suspended?
Have you carefully examined the length of the party wall for similar signs of damp?

Its probable that your neighbour's hardcore, or simply the packed soil under their concrete slab is allowing damp to penetrate sideways into the area behind your skirting. Damp Proof Courses (DPC) are irrelevant in these cases - they will be bypassed.

What do you mean by a "new DPC"?


The first thing to do is to lift and remove all the affected flooring and skirting. Then knock off the plaster back to brickwork to a line 300mm above the last sign of "efflorescence". Remove all debris and pic posts back here.

Given that the Membrane in your kitchen is short then perhaps examine all around the kitchen at floor/skirting level for any other signs of damp.

 

[slimj]

Thanks for the reply dee.

You have a solid floor with a DPM that doesn't lap up behind the skirting, and there is what looks like efflorescence on the wall above. Your neighbour's solid floor is higher than your FFL.

The wood flooring laid over your concrete floor, & the skirting, is rotting with fungal damage.

Spot on yes.

Is the front floor(s), beyond the kitchen, solid or suspended?
Have you carefully examined the length of the party wall for similar signs of damp?

The remaining/other floors are suspended and there are no damp issues. As such the ground water is coming from the ground under my neighbours floor (vertical) or rising up as a result of no damp proof course and the DPM not being tied into the party wall (horizontal)

What do you mean by a "new DPC"?

A new DPC - damp proof course. Given the the location this will need to be chemically injected.

This will get round rising damp from their being no DPC (vertical) but as you say, given the step up in properties, 'they will be bypassed' from the side (horizontal).

This really summarises my initial query - what do I do.

It might be best to install some kind of mesh membrane over the whole wall?

I am trying to plan ahead, but as you say it might be best to strip out and send some better photos at a later date.

Cheers,

slimj

 

[ree]

Chemical DPC's, whether from a tube or pressure injected, are far from being effective barriers - some expert opinions question whether they are of any use at all. From the details that you have posted so far there is no point in installing a DPC.

Its best to do as suggested above (clean out & post pics) - that way, you will hopefully find out how to proceed.

Presumably, your neighbour has a slab in his kitchen, & his front room(s) is suspended?

The rising damp indications that you see on your wall (efflorescence) also indicate that if not now, then later, the damp will penetrate to the neighbour's wall surface.