Failed DPC Injection? & Slate DPC

[Jack07]

Hi,

I noticed that a small area above my skirting board is showing signs of damp as the wall paper was soft and sticky. This a 9" party wall between myself and my neighbour. Ive checked next door and cant really see much.

I removed the wallpaper and it feels damp approx 2' across. Removed skirting and found that it has been previously injected.

What could be the causes? It still feels damp to the touch. I have a few tubes of injection cream left over from previously treating one of my walls and thought about re drilling the holes and re-injecting?

Also I did the same to my front wall as I noticed that approx 200mm below the corner of the window was a small bulge behind the wallpaper. After removing the wall covering and a bit of old plaster a horizontal peice of slate has moved and is poking out.

This is approx 1 metre above floor level. Is this the old DPC? Were they usually so high?

Thanks again.

 

[tony1851]

When they re-plastered the wall after injecting the dpc (assuming it was re-plastered) could they have used ordinary plaster instead of renovating plaster? Rising damp can draw up salts which stay in the brickwork and attract moisture from the air, thus making the area where the salts are deposited permanently damp, and this can sometimes be mistaken for condensation. Renovating plaster is designed to suppress this. (properties treated for rising damp are supposed to have the lower few feet of old plaster completely removed and the walls re-plastered).
Assume you have eliminated the obvious causes such as leaking pipes etc?
If the piece of slate is 1m above the floor, it is unlikely to be a dpc. Could it have just been a piece of packing to level up a mortar joint?
You don't say how old the house is, or whether it is built of brick or stone.

 

[gregers]

if the wall was damp then it still is damp,party walls afaik can only be injected 4 " i:e from your side your neighbours side may still be damp.

 

[Jack07]

Hi,

The house was built around 1930 and is brick built cavity walls.

There is no sign of leaking pipes, they are all surface mounted.

I didnt realise that hydroscopic pipes would still make the walls damp. I thought they just made it still look damp.

I dont think the walls have been re-plastered as it still has the old black stuff. There is a small area that has been re-plastered due to an internal wall being removed. This is adjacent to the damp area and the new plaster has the similar height of damp showing.

I was going to re-inject as I have spare cream and hack off old plaster to just under 1m.

Does this sound like a good way to go about it?

Thanks again.

 

[hotrod]

I was going to re-inject as I have spare cream

 

[Jack07]

I was going to re-inject as I have spare cream

As I was typing that line i had a little chuckle to myself but thought no one would pick it up so didnt bother changing it.

How wrong I was!!!