Damp proofing external walls help

annieb1981

So we had a rogue builder who I have referred to a few times on here! and we have an issue in places where there has been wrong DPC levels in walls, sloping DPC and rubble in cavity helping to bridge moisture across to inside walls. Our current situation is we think this is creating a strange condensing moisture situation in the bedroom with moisture settling on top of the carpet. Not to mention potential long term problems yet to happen. 

We have been advised to chip off a band of plaster around the external walls and paint on a damp proof substance, bitumen or rubber substance like used in swimming pools. We have also been told to dig down as far as we can to apply this substance. The more expensive alternative would be to remove a few bricks at a time, remove any rubble in cavity and add a substance to the inside of the cavity wall- this we cannot afford to do.

Has anyone done anything similar or can advise on this before we start the process if
chipping away plaster? We have been out a lot of money taking this man to court so we are hoping this will be something we can do ourselves as there is no money left to hire in help.
many thanks!

stuart45

If you clean out the cavity yourself it won't be expensive. You don't need to tank your walls.

annieb1981

stuart45 said:

If you clean out the cavity yourself it won't be expensive. You don't need to tank your walls.

How could we do this? They have been filled with ball insulation as well.

stuart45

That makes it more difficult. It's normally cleaned out first. They usually get cleaned from outside by removing a few bricks at the corners and using a long piece of 2x1 with a nail rake the debris back to a few coring holes.
You might be able to get a piece of 2x1 in along the cavity a bit higher up the hold the insulation back.

FreeBear

stuart45 said:

If you clean out the cavity yourself it won't be expensive. You don't need to tank your walls.

Had a cavity here filled with debris that was causing damp problems. Took a few bricks out myself (being a lime mortar, easy enough to do with just a pad saw). Removed several buckets of sand, tile, and cement "snots" before putting the bricks back in.

Depending on when your cavity wall insulation was put in, a binder may have been used to stop the polystyrene pouring out of any holes - Some installers use a glue, others don't.. But you really need to remove the cause of the bridging rather than slapping a bodge over to hide the problem for a few years.

annieb1981

FreeBear said:

stuart45 said:

If you clean out the cavity yourself it won't be expensive. You don't need to tank your walls.

Had a cavity here filled with debris that was causing damp problems. Took a few bricks out myself (being a lime mortar, easy enough to do with just a pad saw). Removed several buckets of sand, tile, and cement "snots" before putting the bricks back in.

Depending on when your cavity wall insulation was put in, a binder may have been used to stop the polystyrene pouring out of any holes - Some installers use a glue, others don't.. But you really need to remove the cause of the bridging rather than slapping a bodge over to hide the problem for a few years.

When you removed the bricks how did you support that section of wall? I really worry if we would have the time and ability to do this ourselves 😩 but I do want it done right. how did you know you got everything out? We had hoped to have got money from our rogue builder having got a judgement against him which would help pay to have this done but it looks like justice works in strange ways!

stuart45

Were you thinking of doing from the inside or outside?

MikeJXE

What do you mean by

Wrong DPC levels ?

Sloping DPC, ?

How do you know there is rubble in the cavity ?

annieb1981

stuart45 said:

Were you thinking of doing from the inside or outside?

The outside 

MikeJXE said:

What do you mean by

Wrong DPC levels ?

Sloping DPC, ?

How do you know there is rubble in the cavity ?

It’s all a mess. When we discovered he hadn’t put in a subfloor and had all removed the surveyor found all the builder levels were wrong so doorways were very high. DPC in some areas are well above floor level and in others were found to slope from outside brick to a brick below on the inside and therefore holding moisture against the inside wall. Total nightmare. We used an inspection camera and can see debris in the cavity.

MikeJXE

It's difficult to work out the best course of action not being able to see, What does the surveyor suggest ? He should be your best bet. 

Depending on where the floor is, where the DPC is,  cleaning out the cavity may not solve the problem 

Is the cavity filled with insulation if so what type ?

annieb1981

MikeJXE said:

It's difficult to work out the best course of action not being able to see, What does the surveyor suggest ? He should be your best bet. 

Depending on where the floor is, where the DPC is,  cleaning out the cavity may not solve the problem 

Is the cavity filled with insulation if so what type ?

He did say best advice is remove bricks and treat the problem from the cavity 😬 clear out and bitumen paint on inside of cavity. The insulation is the beads and are loose. A reputable builder said he felt the bridging of moisture due to the debris was a culprit too so I guess we might have to do a bit of everything. Actually fills me with dread. We wouldn’t have known the effects until the moisture sitting in the carpet. Underneath is bone dry. not even any excess condensation on windows either. One day we literally thought there had been a leak and I took off skirting and lifted the carpet. All was dry but there were very damp patches on top of carpet. Thought my mind was going because couldn’t explain and have put it down to all these other issues. Damp meter definitely picking up the damp in the brick when we exposed an area after taking of skirting and the camera showed the debris.