Damp patch at foot of external wall (ed.)

[Lupus]

It seems that every other post on here at the moment is related to damp in someway or another, but I'm afraid I've got another if anyone could be so kind to please share their opinion.

We have a fairly decent sized lounge measuring around 7.5m by 3.7m. One side of the 7.5m length and both 3.7m widths are external walls, with a chimney breast in the middle of the 7.5m. The wallpaper (okay lining paper, that has been up an embarrassingly long time) in the red area looks damp for a few inches above the skirting board.

On the external wall, the bricks and pointing look in good condition, as does any guttering and roofing. The damp proof membrane looks good with no obvious sign of bridging. We did have cavity wall insulation installed a few years before this first started appearing. Our house is in an exposed position.

I know they're utterly rubbish, but our damp meter (with brick mode enabled) shows the humidity of the wall just above the skirting board to be about 14%, a few inches above where its spotty about 12% and finally a few feet up around 9-10%.

There is a slightly different feel to the paper where it's marked, this could be due to present damp but I'm guessing the texture has just been permanently changed by any previous damp.

My wife previously made some salt-dough learning toys for my little one, one of them was left learning leaning against this wall and it turned really wet and mushy. The other toys in the 'set' were away in the draw and are perfectly dry. Unfortunately I don't know how long it was there for, I'm guessing between a few days and a couple of weeks, but could be wrong.

I'm thinking it would either be:
* Rising damp - highly unlikely as its actually really rare and the dpm seems fine
* Problem with the cavity wall insulation
* Condensation - I would have thought this would be more likely be towards the ceiling

I'd be grateful for any thoughts.

Thanks

 

[Wayners]

Gypsum plaster used instead of lime on renovations. This causes damp.
Non breathable paint trapping moisture in walls.
Cracked concrete or cracks in drain gully flooding water under house. That's common.
No gap between concrete path and house wall causing damp bridge.
Windows leaking down cavity so buy cheap camera and push in to look.
List goes on.
Get it looked at although pick your firm carefully as some are useless from what I've seen.

 

[JohnD]

You don't drape wet washing inside the house, do you?

 

[Lupus]

Thanks for coming back to me. I did get somebody out for their opinion who said it was condensation, but I wasn't 100% confident as its so low down, patchy and only affecting 1/2 the external wall with none the other side of the chimney breast.

In winter we do dry the clothes indoors, but usually have a dehumidifier running in that room at the same time - well as of the last 3 months or so.

 

[JohnD]

Show a picture of the outside please. Indicate the DPC and airbricks. High enough to show the gutters

In your drawing, where are the window and the radiator?

When did you last hang wet washing in that room?

Do not allow anyone into your home who sells silicone injections.

 

[Lupus]

I've dug out an old floor plan I done yonks ago as I thought it might help. There is a radiator opposite the fireplace and under the window at the front.

I've marked on in red where its worse (as in the initial photo), yellow where its a bit better and green where there is only a slight faint line above the skirting board. I just noticed some minor water marks above the radiator, but this is no where near where its worse so probably not related. The original photo is roughly where the yellow arrow is pointing, I've attached two more pictures marked by white arrows.

Previously clothes were hung to dry mainly in the kitchen or the snug, it would be extremely unusual for them to be hung in the lounge.

These photo's really make the room look disgusting, apologies. We've been wanting to get a porch built for years and held off decorating this room properly until we do. Unfortunately with affordability, a huge mortgage and continuous surprise expenses its always been 'next year' and now its just tragic and desperate!

I'm working from dark-til-dark at the moment, but will take some external photos either tomorrow or Tuesday and post those.

Thanks again for your time.

 

[JohnD]

What is on the other side of the wet wall?

Is the floor concrete?

 

[Lupus]

Sorry for the delay in coming back with the other pictures, I've been doing silly long hours at work and kept missing the daylight!

The floor is a suspended floor, that part of the house was built around mid-50's if it helps. At the front of the house there is a 'lawn', the top of it comes up to about a bricks height below the DPC.

The side of the house was 'mud' until about two years ago. With the DPC about 1-1.5 bricks beneath the DPC.

I then lowered the 'mud' by 1.5-2 bricks of height, and laid a layer of 20mm gravel and currently storing some spare bricks on top of the gravel, though there is a gap between this and the wall. The DPC is now at least 2 bricks above the gravel level and probably about 3 above the earth.

If it wasn't for the 'wet' salt-dough toy against the skirting board, I would have assumed that it was no longer an issue and resolved by lowering the 'mud'. Which was why I was initially wondering about the cavity wall insulation.

Below is view from the bottom of that wall looking up.

Thanks again.

 

[JohnD]

Your picture with the grass shows noticeable efflorescence below the DPC, suggesting the ground is quite wet, with hard water.

I get that going two bricks above ground level, then it stops (this is below the DPC)

I presume the retrofit grills are to keep mice out. They may obstruct airflow.

Surprisingly there are no visible drains, though I see a downpipe on one corner. Is it near your damp patch?

Do you know where the water goes?

As you have a suspended floor, you can take up some boards to see what damp is below.

 

[foxhole]

Is the chimney capped and vented

 

[foxhole]

I've dug out an old floor plan I done yonks ago as I thought it might help. There is a radiator opposite the fireplace and under the window at the front.

I've marked on in red where its worse (as in the initial photo), yellow where its a bit better and green where there is only a slight faint line above the skirting board. I just noticed some minor water marks above the radiator, but this is no where near where its worse so probably not related. The original photo is roughly where the yellow arrow is pointing, I've attached two more pictures marked by white arrows.

Previously clothes were hung to dry mainly in the kitchen or the snug, it would be extremely unusual for them to be hung in the lounge.

View attachment 287875

View attachment 287869
View attachment 287873

These photo's really make the room look disgusting, apologies. We've been wanting to get a porch built for years and held off decorating this room properly until we do. Unfortunately with affordability, a huge mortgage and continuous surprise expenses its always been 'next year' and now its just tragic and desperate!

I'm working from dark-til-dark at the moment, but will take some external photos either tomorrow or Tuesday and post those.

Thanks again for your time.

Drying washing indoors affects the entire home not just the rooms used for the washing .

 

[Lupus]

Is the chimney capped and vented

Yes.

Your picture with the grass shows noticeable efflorescence below the DPC, suggesting the ground is quite wet, with hard water.

I get that going two bricks above ground level, then it stops (this is below the DPC)

I presume the retrofit grills are to keep mice out. They may obstruct airflow.

Surprisingly there are no visible drains, though I see a downpipe on one corner. Is it near your damp patch?

Do you know where the water goes?

As you have a suspended floor, you can take up some boards to see what damp is below.

The front of the house is permanently in the shade, so when wet the ground there will probably take a long time to dry out.

The MouseMesh vent covers were installed a couple of years ago, not saying that don't make things worse but it was after the damp initially appeared.

The visible downpipe runs down into the bottom right of my house plan, labelled DP. So yes, where it's damp. I tried to see where this was going when I lowered the dirt and laid gravel, I can say its an underground pipe but couldn't really tell with enough confidence where it goes or what state it's in. I thought at the time it went forwards towards the lawn, I'd then guess it bent round to cut across the front of the house to join up with the main pipe - but that is a guess.

The lounge has wooden floor laid over floorboards, it's been stuck somehow so if I take it up I'm potentially not going to be able to refit it in any reasonable state.

Drying washing indoors affects the entire home not just the rooms used for the washing .

It probably is condensation, but it's not where I would expect it and as its only on those two walls it could be something else and I'm quite a paranoid person anyway!

Thanks again, I really do appreciate you both taking the time to help.

 

[JohnD]

Is there any sign the downpipe is overflowing or leaking?

 

[Lupus]

No, all looks in good order and it only collects from one side of a gable and perhaps 2m of main roof that 'feeds' into that gable.

 

[winston1]

What is that bit of plastic doing in the right hand mains socket? It is dangerous, remove it and bin it.

FatallyFlawed