Damp on granddads house since they built next door

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Venche

New Member
So. 6 years ago they built a house next door to my mates granddad. He is end of terrace and the new house foundations lifted the ground level on that side of the house so the internal floor is now about 40cm below the outside ground level.

The picture below shows the outside. Inside the house the floor about 1m below the top of the render.

there has never been much of a problem but this summer a lot more people have been living in the house, and over the last few weeks the heating has been on more than usual and damp has appeared.

The second photo shows the damp that has appeared. This line runs the length of the dining room (back of house) and the center of the damp is perfectly in line with the top of the render. It has spread about 20cm upwards and downwards. the living room (front of house) also on the same wall with the same render but has had no issues.

There is no damp at the bottom of the wall, or anywhere else.

My proposed solution is to take the plaster off, back to the brick, put permagard from 4cm off the floor up to about 1m above the damp, then affix batons vertically to the wall above the permagard and dot and dab plasterbaord on the permagard + screw into the batons above the permagard. Then glue skirting to the bottom.

My thinking is that this is a 140 year old house, so I don't want to go nuts with the permagard as it has to breath. and I just use the permagard to cover the damp area so it does not come through to the rest of the house. leaving the air gap at the bottom and top I hope lets it breath.

He does not have much money so going to do the job for him at cost - ideally keeping these as low as possible!

Any ideas / suggestions welcome.

Thank you.

Also - The people who built the house next door are long gone unfortunately!
 

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ChrispyUK

Well-Known Member
So. 6 years ago they built a house next door to my mates granddad. He is end of terrace and the new house foundations lifted the ground level on that side of the house so the internal floor is now about 40cm below the outside ground level.

The picture below shows the outside. Inside the house the floor about 1m below the top of the render.

there has never been much of a problem but this summer a lot more people have been living in the house, and over the last few weeks the heating has been on more than usual and damp has appeared.

The second photo shows the damp that has appeared. This line runs the length of the dining room (back of house) and the center of the damp is perfectly in line with the top of the render. It has spread about 20cm upwards and downwards. the living room (front of house) also on the same wall with the same render but has had no issues.

There is no damp at the bottom of the wall, or anywhere else.

My proposed solution is to take the plaster off, back to the brick, put permagard from 4cm off the floor up to about 1m above the damp, then affix batons vertically to the wall above the permagard and dot and dab plasterbaord on the permagard + screw into the batons above the permagard. Then glue skirting to the bottom.

My thinking is that this is a 140 year old house, so I don't want to go nuts with the permagard as it has to breath. and I just use the permagard to cover the damp area so it does not come through to the rest of the house. leaving the air gap at the bottom and top I hope lets it breath.

He does not have much money so going to do the job for him at cost - ideally keeping these as low as possible!

Any ideas / suggestions welcome.

Thank you.

Also - The people who built the house next door are long gone unfortunately!

The problem is external. You need to sort that first.
 

Venche

New Member
Thank you.

The thing is that next door have built right up to the house - so that the bottom few feet of that wall is essentially now underground.

I can’t change that, so do you have any thoughts on what I could do?
 

Venche

New Member
Yep - the builder is long gone unfortunately! Any tips on what I can do, internally, to fix/make the problem better?
 

ChrispyUK

Well-Known Member
Thank you.

The thing is that next door have built right up to the house - so that the bottom few feet of that wall is essentially now underground.

I can’t change that, so do you have any thoughts on what I could do?

Could be multiple issues adding up. By building up the ground, you’ve lost the air bricks and underfloor ventilation on the end of the house (unless the floor is concrete). If it’s floorboards, I’d pull up a few and see if there’s any obvious signs of water getting in. You don’t want rotten floors!

Check the top of the render to make sure water isn’t getting down the back of it.

These are easy things to check first.

I’m guessing the render was applied when the new house was built, in an effort to stop penetrating damp, but you’ve no idea if it was done properly or how far down it goes from the ground level. Find the worst bit internally then dig down externally to see what’s going on. There’s also no drains there by looks of it, so surface water will just work it’s way down the side of the house.
 

Venche

New Member
Thank you.

The floor is concrete - no signs of damp at floor level at all.

The render looks in good nick - when it rained last there was no sign of any lasting damp on the outside around the render.

I’m hesitant to start digging up on the neighbours land, their building is within a meter of this house. There are paving slabs and god knows what else to consider.

Does anyone think it’s possible to isolate the damp on the inside with something like permagard? Or is that a fools game?

Thank you!
 

John j

Mono Don
Could be multiple issues adding up. By building up the ground, you’ve lost the air bricks and underfloor ventilation on the end of the house (unless the floor is concrete). If it’s floorboards, I’d pull up a few and see if there’s any obvious signs of water getting in. You don’t want rotten floors!

Check the top of the render to make sure water isn’t getting down the back of it.

These are easy things to check first.

I’m guessing the render was applied when the new house was built, in an effort to stop penetrating damp, but you’ve no idea if it was done properly or how far down it goes from the ground level. Find the worst bit internally then dig down externally to see what’s going on. There’s also no drains there by looks of it, so surface water will just work it’s way down the side of the house.
You heard this fatha @essexandy . Google been busy
 

ChrispyUK

Well-Known Member
Thank you.

The floor is concrete - no signs of damp at floor level at all.

The render looks in good nick - when it rained last there was no sign of any lasting damp on the outside around the render.

I’m hesitant to start digging up on the neighbours land, their building is within a meter of this house. There are paving slabs and god knows what else to consider.

Does anyone think it’s possible to isolate the damp on the inside with something like permagard? Or is that a fools game?

Thank you!
Give them a ring.
 

essexandy

The Lake Governor
Contact building control and ask if the house has been built according to the plans that were passed. There is no way on earth that permission should have been given to raise the ground level up the existing property. Either planning were at fault or building control didn't do their job. The cost of remedying this issue should not fall on granddad.
@ChrispyUK put that in your pipe and smoke it.
 

ChrispyUK

Well-Known Member
Contact building control and ask if the house has been built according to the plans that were passed. There is no way on earth that permission should have been given to raise the ground level up the existing property. Either planning were at fault or building control didn't do their job. The cost of remedying this issue should not fall on granddad.
@ChrispyUK put that in your pipe and smoke it.
Correct
 
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