Damp Proof Injections

[hansPulesh]

Hi all,

I've been having major issue with damp patches on an external wall. I live in an end of terrace property and the outside flank wall seems to have a major amount of damp in the middle of the wall - none of the render is loose on the outside.

I can't for the life of me work out where the damp is coming from.

I've had a number of damp experts in and they have not managed to isolate the reason for the damp.

They have however all advised a damp proof course consisting of injections is put in place. How is this done?

I'm pretty hands on and have built my own extension in the past and so have no problems tackling this by myself just as long as I first understand the technicalities behind the process.

I've been advised to

1. Strip the wall back to brick from the inside
2. Use a waterproof paint on the brick work.
3. Use PVA in waterproofed sand and cement - apply this to the wall.
4. plaster over this.
5. On the outside, drill holes and inject the waterproofing solution into these.

Firstly, is this correct?
Secondly, how far apart should the injections be? Which solution is best to use?
Which waterproof paint is best to use on the inside?
Is there specific sand and cement mixture tht should be used? which other additives should be added to the mixture?

Many thanks.

 

[stuart45]

I've had a number of damp experts in and they have not managed to isolate the reason for the damp.

You need to find the cause of the damp before you can fix it.

 

[gregers]

if your walls are cavity then theres no need to drill/inject the outside skin.
before you plaster then remove the bricks to form a hole about 8"x8" then using an ades or a flat bar/hook remove the crud from within.
as for injecting it depends on the solution?
usually its 2 in the stretcher and 1 in the header,or at roughly 45 degrees into the motor course.
or research on creams.

 

[theprinceofdarkness]

In a house where we once lived we had this. It was that in days gone by the wall had been damp proofed by nailing some patent bitumiuos cardboard to the wall. This stuff was corrugated at every 1/2 inch or so, so there were these channels running vertically through which the wall was meant to dry out. It dried the wall by depositing the dampness into the plaster where this stuff stopped. We only found it when we knocked a wall down for an extension. Never did cure the damp patch at a level of 5' on a party wall in the front room.
Frank