Damp Internal Wall

[psd99]

Hi all,

I got a wall in my hallway that is suffering from damp troubles.

This is what it looks like inside and outside:






The paint is bubbling up, 2 years ago I got all of that external wall treated with an injection on the outside.
The internal wall has been re-plastered 2 years back. It all looked good for a while but the damp to re-appear.

The internal wall to my surprise when I got the property (6 years back) is actually plaster board, I did wonder why plaster board was used here, when the rest of the walls are brick/block.

Looks certain there is something I need to to do the outside of the wall but what can I do to stop/halt the internal damp coming through?

 

[psd99]

that is a brand new air brick
been there since the world cup - pretty sure inside was good and fairly clean.

 

[psd99]

Is there any potential source for sub surface water nearby? No chance of a blocked drain or anything?

What material is below the bottom of the white painted bricks?

Injection treatment is a total con.

there is a gutter above but it is very far.

Looking at the first picture on the right hand side some of the cement is broken - I wonder if another layer of cement on top of the black paint bit will help.

the floor is concrete, it's a part of the house that wall never gets much sunshine so lots of algae on the floor etc.

 

[psd99]

there was damp in other places but since the injection that doesn't occur
it's only on this small part where the issue is

it's a 1930's build almost 90-100 years old. I suspect that is a cavity wall as I could never work out why the inside wall is plasterboard.

what do I need to use to clean the outside of the bricks? I will prob do this in spring/summer but just looking for advice now

I got gut a feeling that the previous owners at some point took all of the internal bricks/blocks away and changed it to plaster board probably for the same reason as I'm putting this post up for.

 

[psd99]

ummmm, then you really need to get that checked out. If that is a cavity wall then the internal wall is actual the wall that holds the loads of the house the external brick work is normally just the skin you really need to get that check out as you might currently be having issues with your house sinking in that area and yes if you have no block work or brick there then that will easily be what your issue is since the water is just soaking through the out brick skin into your house.

Regarding the outside of the house, try and bursh some of it off on the mortar for now as this will allow the water to escape from at least between the bricks. If you leave it like this eventually the bricks will start spalling.

what am I brushing off of the wall and how do I know exactly where to do that?

30’s may be either solid wall or cavity. The plasterboard will be dot and dab (boards stuck on with ‘adhesive) which will usually have a small void behind it. It definately wont just be one skin!

Check airbricks for flow and gutters for leaks. What is the room used for?

It is in the hallway when entering the property, I can check the airbrick by poking something into it possibly but the gutters do need a clean but don't have a ladder to do it, one on the list.

Hallway can be hot and cold together, the front door is old and has condensation/mould on it, they are plans to change it in the future with a new porch. (no porch currently)

I know this is also a problem, but got to wait to build the pot up first.

On the left of the internal view there is a return, is there a window there or a door?

that is a little coupboard that houses the electric main box

I will look inside there but pretty sure it's generally okay under there.

Remove the paint as a first step and then look at removing the concrete. The concrete is a big slab right next to the wall stopping proper drainage. You want a french drain against the wall with sufficient shingle to allow any rainwater to rain down through the shingle into the submerged drain and away from the house. It also stops “splash back” so the wall generally stays drier.

You want a gap at least 3-5 inches from the brick wall and after that you can patio it as normal. Did this at a similar house I used to own and it completely cleared it. Also the concrete path is ugly!

Thanks I think this is a good suggestion but this is on a shared driveway. Where do I stand on making this change?

I don't believe I got a drain near by, there was one but it got concreted over a few years back as it was no longer required.

 

[psd99]

how deep will it need to be? - it is the side of the house - but not all of the house has this problem though.

 

[psd99]

yes it is a suspended floor what difference does it make?

 

[psd99]

Just pointing out that the air brick isn't ventilating between layers of brick it's ventilating under the suspended floor.

I would assume the issue is as others have stated.

Lack of drainage up the wall and splashback onto the bricks with the painted finish is retaining moisture in the wall

but why would it only be an issue on this part of the wall - the rest of the wall is okay

I will check the gutters + airbrick to see if it helps, then perhaps that pea shingle approach will be the best long term in this case.

 

[psd99]

thanks I will look at this soon.

I don't have any way to look under the floor except taking the skirting board off, floorboards off etc

wire brush - do I need to go back to the cement/mortar?

I guess the paint will flake off.

 

[psd99]

have a look at it - does the wall feel wet after its stopped raining for a few hours? is there actual water behind the paint? is the paint starting to bubble up because the water behind it cant escape? You might have an issue that its not just the paint that is causing the issue, looks like some of that wall has been repointed. If the house is old and they have used a cement mortar instead of an lime mortar that will also trap the moisture in the brick work.

Are you 100% sure you dont have a water leak somewhere in the house? Next time you go out turn off all the taps in house so nothing can use water. Check the meter and see what the numbers are, then when you return say 3 hours later check them again, this should tell you if you potentially have a hidden leak somewhere in the house.

I doubt it is a leak because the internal wall gets worse when it rains more
so it's got to be the rain water

it was okay in the summertime, unless a magical leak has emerged somewhere.

the only water pipe we got is the mains water but it is far out from the wall

 

[psd99]

thanks all, the weather is picking up here from the weekend so I will try some of the basic suggestions. It definitely has got worse over the last year.

I'm also in touch with the person who did the external wall damp injections just to get their input.

 

[psd99]

Ok the plan this weekend according to this thread is:

- Clean the gutters above
- Wipe off of the blistering paint with a brush.
- Clean inside the air brick


then I will leave it like this for now and hope to see a difference before implementing the potential soakaway!

should I also remove the paint on the inside wall to let everything breathe properly?

 

[psd99]

It's going to look terrible leaving that off like that, not to mention the coldness. but we'll see how it goes.

 

[psd99]

Ok thanks

- gutters are fine
- paint does not easily come off with a wirebrush

there is conflicting advice on this forum about using a chemical remover to get the paint off

despite that if i did get the paint off
Its going to look rubbish
Whats the long term plan? Paint over it again?

 

[psd99]

ok took some point off today with a filing knife
but absolutely no sign of the DPC or something of that sort

I am Fairly certain that air brick is below the suspended floor and it was there originally prob from the 30's
except I replaced the air brick with a newer one, rather than the cast iron one from before

 

[psd99]

Ok thanks

it is hard to tell if I have a slate DPC as there is white paint everywhere.

 

[psd99]

Yep good points

I am certain that internal wall has been replaced with plasterboard I suspected something about then when I purchased the house 5/6 years back.

This could have been a problem for a while and thats why the previous owner boarded the hallway, so I am wondering if there is a chance those plasterboards are waterproof already

Mr injector responded back telling me that he can’t help me under his gurantee as his team did not do the internal plastering work
Basically he is being useless
I suspected this would be the case

how long have water proof plaster boards been around?

 

[psd99]

I think it would be best to break that internal plasterboard up to see what is really going on before taking further action

but it is not a good time of year to do this right now as it will make the hallway extra cold and that’s the place I got my nest in.

 

[psd99]

I'm renovating a 1930's house and had issues with water under the floor when it rained.
Luckily as I'm renovating I could lift the floorboards, the root cause was perished mortar joints in the footings.
Only 2 or 3 tiny pinholes would let in a lot of water over a day! Tracing dye was invaluable.
Whats the slope of the property, would water accumulate against that wall in that area?
I note the damp tide mark is higher towards the return. Do you potentially have a dwarf wall under that return? Where water may pool up against it.
If you have a carpeted area nearby where you could lift a couple of floorboards and get your head in with a torch would be my thinking.
I'd do it after a decent rainfall if so.

I do notice that there is a slight gap between the concrete on the floor and the wall
is that what you meant?

The slope is fairly flat, I don't think water goes up against the wall but there are definitely gaps there in that area.

 

[psd99]

I am not sure if it is a dwarf wall

the area has laminate flooring I agree about lifting it up one day and checking underneath.