Newly fitted basement window - bulging walls and damp

Hi all,

Looking for some advice on next steps.

We had a new upvc window fitted to our basement in June last year that involved digging out a large section of earth, laying some stones in the base and bricking up the dug-out section (see photo 1).



However, in September we noticed mould, discolourations in the plaster and what looks like salt in various patches on the plaster surrounding the window (see photos 2-4). It's worth noting that these surfaces were at this moment mostly plumb, with a good space between the wall and the inner window frame, with the window opening easily.



When we had the painter come in to get the whole room prepped, he said it was likely to be damp related and he'd see if he could patch-up any gaps in the sealing on the outside of the window and then once the plaster dried out it should be fine... He got to work and had the whole room painted in a week, it looks fantastic, very pleased, yadda yadda yadda.

Anyway, we've been noticing the walls around the window frame slowly but surely bulging with cracks appearing in the plaster and small sections of paint flaking off. We had asked the cowboys responsible for this mess to come back and sort it a few months back but obviously they're still awash with funerals, dentists appointments and the like. This morning I had a proper look and took a few photos to try and get some idea of what to do (see photos below).



The walls are now bulging by between 10-15mm on each side directly by the frame, and the sill underneath is bulging by about 11mm in the centre, flattening out towards the corners. The window now no longer opens easily, and has cracked the plaster where it meets the wall when opening.



As you can see from the picture above, pebbles were laid, but are practically level with the window frame, and the builders threw the rest of their plaster/cement/grout over the pebbles, creating a lovely layer of mush. I'd imagine this is also affecting the waterproofing of the window frame, but any advice on this would be appreciated.

I'll follow up this post with a load of photos of the outside of the window.

My main questions are:

- Is this likely to be damp-related or are there possibly greater structural issues at play?
- Is this purely an issue relating to the plaster or could the brickwork be compromised from ingress of water?
- Can this be solved with a bit of elbow grease and diy, or should I try and get another set of builders in to fix the issue?

Also, I doubt this is on the cards with them disappearing into the wind, but if it's worth trying to pursue the old builders in any way, then any advice on how to do that would be massively appreciated.

Thanks all, I can take more photos as necessary but thought I'd prioritise with these as I can only have 10 in a post.

Thanks,
Oscar

Exterior situation:



I believe the black sealant is the painter's attempt to seal the outside but I'm not sure it's particularly effective.

Thanks,
Oscar

Oscar,
Why not stand back and photo what looks like an areaway, and then the whole of the rear elevation?

On the RH side there seems to be an opening ? What is it, does it go somewhere else in the basement?
What kind of lintel has been installed above the new window opening?
Have any cracks appeared on the outside or the inside wall surfaces?
Look at the floor/skirting board in the room above the window - any gaps under the skirting?
There are other issues but for now just a few questions

The painter was talking nonsense - the only thing he succeeded at was taking your money.

SaggingBeams said:

My main questions are:

- Is this likely to be damp-related or are there possibly greater structural issues at play?
- Is this purely an issue relating to the plaster or could the brickwork be compromised from ingress of water?
- Can this be solved with a bit of elbow grease and diy, or should I try and get another set of builders in to fix the issue?

Click to expand...

Is the basement made of cavity wall construction?
what is the basement wall construction detail under the plaster?

the plaster on the window reveals should not be touching the external brickwork at all or damp is inevitable -I suggest taking a chisel and hammer and knocking off some of the plaster so we can see what theyve done underneath


Externally, the gravel is way too high -it should be 150mm below the window cill really

is there any form of drainage under that gravel -if theres nothing for drain away the water, that area could just fill up with water

Hi Ree and Notch,

Thanks for a quick response. Here's a photo of the wider area, the condition of the walls is a little tricky to work out as they're covered by two large mirrors, but considering there's no movement or cracks on the wall facing into the room I'd be surprised if the problem was also there.



There's no visible cracking or damp throughout the rest of the room or under the lintel on the inside of the top of the window. At the edge of the sill on the right side there is a small bit of cracking, same as the bulging around the window.




Onto the lintel:




It looks to me like they've used brick here, though whether they've simply left the old bricks not removed where they were, or installed an actual lintel isn't clear. They certainly don't look like 8 month old bricks though.

ree said:

Oscar,
Why not stand back and photo what looks like an areaway, and then the whole of the rear elevation?

On the RH side there seems to be an opening ? What is it, does it go somewhere else in the basement?
What kind of lintel has been installed above the new window opening?
Have any cracks appeared on the outside or the inside wall surfaces?
Look at the floor/skirting board in the room above the window - any gaps under the skirting?
There are other issues but for now just a few questions

The painter was talking nonsense - the only thing he succeeded at was taking your money.

Click to expand...

Smoke and mostly mirrors, the room used to be a gym and still has the old mirrors on it. The basic floorplan I made has the layout of the room.

- Apart from the cracks shown in the pictures so far internally and externally, there aren't any others that have appeared.
- No obvious gaps under the skirting in the room above, it's a victorian terrace house so the floorboards are pretty gappy, but there's been no cracking or damp in the room above.
- In the painter's defence, he didn't ask for any money for it. But obviously, just painting over the issue doesn't fix it and means it'll need to be redone.

Notch7 said:

Is the basement made of cavity wall construction?
what is the basement wall construction detail under the plaster?

the plaster on the window reveals should not be touching the external brickwork at all or damp is inevitable -I suggest taking a chisel and hammer and knocking off some of the plaster so we can see what theyve done underneath


Externally, the gravel is way too high -it should be 150mm below the window cill really

is there any form of drainage under that gravel -if theres nothing for drain away the water, that area could just fill up with water

Click to expand...

To be honest I'm not sure if it's a cavity wall, though I doubt it based on the pictures below.

Have had a bash about and there's quite a strong smell of mould and damp coming from the feature hole I've just installed.


It looks as though they've slapped a load of mortar into the hole and left it there, with the mortar then touching the back of the plaster and allowing moisture to pass through. It's very soft and easy to push through with a chisel, and is damp to the touch.



I also had a poke at the small cracked section under the sill, which looks similarly not right.



Back outside, I had mentioned the issue of drainage whilst it was being worked on and never received an answer on that. I haven't noticed any pooling of water but regardless I think I'll dig up what they've laid and go another 150mm deeper as you say, relaying the gravel and removing the plaster and brick dust they left behind.

Thanks,
Oscar

OP,
A photo of the whole elevation would still help?

The small patch of visible render has perished - it needs to come off, & be replaced by sand & lime render.
Is there render over the whole elevatiion or just on the bay?
The arch over the window opening would usually be a brick, soldier arch. Looking up from below its hard to tell whats happening with the arch?
The soil and pebbles can be lowered but soil areaways are very difficult to drain.

Inside I would remove the mirrors and carefully examine the walls for water penetration.
Where you have opened the reveal might mean some bricklaying is going to be needed - why not try & hole the other reveal and have a look?
All plaster that looks to be water damaged should be removed back to brick to brickwork, and replaced with sand & lime render.
Plastic corner beads, not metal beads, should be used.

Or you could go in for tanking all the inside water damage.
I'd stick with rendering and replacing the render in say 10 yrs or more?

ree said:

OP,
A photo of the whole elevation would still help?

The small patch of visible render has perished - it needs to come off, & be replaced by sand & lime render.
Is there render over the whole elevatiion or just on the bay?
The arch over the window opening would usually be a brick, soldier arch. Looking up from below its hard to tell whats happening with the arch?
The soil and pebbles can be lowered but soil areaways are very difficult to drain.

Inside I would remove the mirrors and carefully examine the walls for water penetration.
Where you have opened the reveal might mean some bricklaying is going to be needed - why not try & hole the other reveal and have a look?
All plaster that looks to be water damaged should be removed back to brick to brickwork, and replaced with sand & lime render.
Plastic corner beads, not metal beads, should be used.

Or you could go in for tanking all the inside water damage.
I'd stick with rendering and replacing the render in say 10 yrs or more?

Click to expand...

In this instance would the whole elevation refer to a photo of the front of the property, where the window is located? As full a frame of the front of the house including the window as possible? I'll take some photos in the morning, and can knock up a drawing of the front exterior if that would be helpful.

It's my mother's property so all of the building work was done when I wasn't there unfortunately, part of the reason I'm only getting to it now. The front of the house is only partially rendered. There was a small window located there prior to this new one, so the builders carved out a bigger hole and plugged the new window in.

I've since found out they insisted no lintel was required, so I'm not exactly sure where that leaves us regarding building regs and structural integrity...
The bricks above the window are those that were in place before, for the prior window, which was considerably smaller but the same width. I don't think I have any photos or measurements of the old window to hand, will ask and see.

If lowering the soil and pebbles is a good first step without affecting structural integrity for the exterior then I'll get on that first.

Was never a massive fan of the mirrors so will get those removed in time and have a look behind for water damage, fingers crossed.

If all of the compromised render needs to be replaced anyway then I'll have a bit more of a dig around surrounding the frame to get a clearer picture of what's going on behind the walls.

I think I'd rather go with your original suggestion of rendering than attempting to retroactively tank the areas affected, seems far more sensible to my untrained eye.

Thanks again for your help, it's really appreciated.
Oscar