Help identify source of dampness?

[Pollyanna]

I'm staying at my partner's house while my own is being reinstated after flooding. We found this behind the furniture in the corner of my bedroom when we were spring cleaning yesterday. Could anyone help me identify what's going on here and how it can be fixed? The walls are on the outside corner of the house.

[ToughButterCup]

Go outside to the same corner as shown here. Take a photo of the wall - see if you can get the damp proof membrane in the shot,  and post it here, please? 

Why?

To see if the source of the water / dampness has anything to do with the level of soil in relation to the damp proof membrane - or not.

 

It doesn't look to serious .........

[TonyT]

Outside wall, furniture nearly against wall, lack of air movement if there are no external issues  as toughbuttercup is pointing out.

[Pollyanna]

21 minutes ago, ToughButterCup said:

Go outside to the same corner as shown here. Take a photo of the wall - see if you can get the damp proof membrane in the shot,  and post it here, please? 

Why?

To see if the source of the water / dampness has anything to do with the level of soil in relation to the damp proof membrane - or not.

 

It doesn't look to serious .........

[Pollyanna]

Oops.

Edited May 29, 2023 by Pollyanna

[Pollyanna]

Sorry, struggling with the ins and outs of the forum. Here is the other photo which I have now managed to resize.

[ToughButterCup]

Ha!

See the air brick ....?  It looks a tiny bit '... low...' to me. Probably doesn't make too much difference, but it might .

The rest of the wall looks well maintained - recently well-painted, and there's a proper drip strip to absorb splashes.

 

I'd try and clear round that corner - strip the carpet back. Take a pic and we'll all have a look.

Thanks

Ian

[Pollyanna]

16 minutes ago, ToughButterCup said:

Ha!

See the air brick ....?  It looks a tiny bit '... low...' to me. Probably doesn't make too much difference, but it might .

The rest of the wall looks well maintained - recently well-painted, and there's a proper drip strip to absorb splashes.

 

I'd try and clear round that corner - strip the carpet back. Take a pic and we'll all have a look.

Thanks

Ian

I thought the air brick looked low too. The drive slopes down from the garden to the house and partner says the integral garage (which is adjacent to this bedroom) gets flooded if it's very heavy rain. Here are the pics.

[ToughButterCup]

Right: you seem to me to be saying that the area round that corner gets occassional  '  ... secondary ... ' flooding. 

There's your water-path then.

 

Divert it somehow

• French drain?
• deeper splash strip?
• lower the splash strip to below the air brick?
• all three?
• Catch the water coming down the drive and route it somewhere 'safe' ?

Photo of your drive / garage / water path? Please, if that's intrusive, a sketch?

 

[Pollyanna]

39 minutes ago, ToughButterCup said:

Right: you seem to me to be saying that the area round that corner gets occassional  '  ... secondary ... ' flooding. 

There's your water-path then.

 

Divert it somehow

• French drain?
• deeper splash strip?
• lower the splash strip to below the air brick?
• all three?
• Catch the water coming down the drive and route it somewhere 'safe' ?

Photo of your drive / garage / water path? Please, if that's intrusive, a sketch?

 

OK I took a photo of the garage from the highest point of the drive, one from the side so you can hopefully get an idea of the slope, and one of the top of the drive from down by the garage which shows the busy four lane road that's outside the house. Hope this is helpful.

[Pollyanna]

[SteamyTea]

Is that downpipe flooding the area?

 

[ToughButterCup]

I wonder @Pollyanna, do you know if there is a soak-away for the surface run-off ? 

I'd like to scratch that really well manicured red gravel off and see what's underneath it. If its builder's rubble or  MOT1 (builder's sub-base that compacts to form a semi impermiable layer) , then that layer could  (stress could) be fairly dense and keep the water near the surface.

 

Add  @SteamyTea's point (run off from the roof) and you might  have the cause of your problem.

 

First  job now -  where does the surface and roof run-off water go?  Hopefully a working soakaway. 

If NOT then bingo, there's your answer.

 

 

Edited May 29, 2023 by ToughButterCup

[SteamyTea]

3 minutes ago, ToughButterCup said:

 

If NOT then bingo, there's your answer

Careful, could be other things, burst water pipe, blocked gutter, blown render (what happened to my house) badly fitted window.

 

@Pollyanna, your roof has a good angle for winter PV production, which way does it face and how much shading does it get on the sunny side?

[ETC]

The external ground level at that point is too high - it looks like it’s the same height as the DPC and sub-floor ventilation. Surface water is by-passing the DPC. Pull the gravel back so that it’s about 250mm below the DPC and see if that does any good. Clear out the vents and let everything dry out. Going forward you’re going to have to reduce the ground level.

[Pollyanna]

1 hour ago, SteamyTea said:

Is that downpipe flooding the area?

 

Not as far as we know.

[Pollyanna]

1 hour ago, ToughButterCup said:

I wonder @Pollyanna, do you know if there is a soak-away for the surface run-off ? 

I'd like to scratch that really well manicured red gravel off and see what's underneath it. If its builder's rubble or  MOT1 (builder's sub-base that compacts to form a semi impermiable layer) , then that layer could  (stress could) be fairly dense and keep the water near the surface.

 

Add  @SteamyTea's point (run off from the roof) and you might  have the cause of your problem.

 

First  job now -  where does the surface and roof run-off water go?  Hopefully a working soakaway. 

If NOT then bingo, there's your answer.

 

 

Is this a soak-away, it's just in front of the garage door? I scratched off a wee bit of the gravel in a couple of places and it just seems to be a very thin layer of chips laid on top of hard compacted earth. The water from the roof runs down that drain pipe in the corner and as far as we know, that's working fine (not blocked).

[Pollyanna]

41 minutes ago, ETC said:

The external ground level at that point is too high - it looks like it’s the same height as the DPC and sub-floor ventilation. Surface water is by-passing the DPC. Pull the gravel back so that it’s about 250mm below the DPC and see if that does any good. Clear out the vents and let everything dry out. Going forward you’re going to have to reduce the ground level.

That sounds logical, we'll have a look at it tomorrow and see what we can find out. Thanks.

[Pollyanna]

2 hours ago, SteamyTea said:

Is that downpipe flooding the area?

 

No, don't think so.

[ToughButterCup]

10 hours ago, Pollyanna said:

Is this a soak-away, it's just in front of the garage door? I 

 

It could be.

Test it with a hose. I'm with @ETC above. It seems to me that the gravel is possibly a visual distraction from the reality.... All the front area is in effect a solid or semi solid surface.

 

That said, the problem could be worse. Test that soakaway first. Run a hose on it for a while. If it backs up, then it's blocked. 

 

[Pollyanna]

12 hours ago, ToughButterCup said:

 

It could be.

Test it with a hose. I'm with @ETC above. It seems to me that the gravel is possibly a visual distraction from the reality.... All the front area is in effect a solid or semi solid surface.

 

That said, the problem could be worse. Test that soakaway first. Run a hose on it for a while. If it backs up, then it's blocked. 

 

Hi. I've tried running the hose as you suggested, and the soakaway seems to be holding its own BUT, if you look at that slab to the left of the drain it slopes downwards towards it, so the water running down those slabs past the drain seems to just pool in that area which is right next to the wall where the stain is.

[Radian]

1 hour ago, Pollyanna said:

if you look at that slab to the left of the drain it slopes downwards towards it, so the water running down those slabs past the drain seems to just pool in that area which is right next to the wall where the stain is

So that would soak the external brick leaf but how is it tracking across to the internal? It may be a cavity full of mortar snots or other rubble from when the house was built, it may be something else bridging the cavity. Has the cavity been filled with insulation?

Or do you see evidence of any ants in the vicinity. Ants have a penchant for gathering soil and transporting it to a void in which they construct a nest. Some species even favor a damp soil.

[Pollyanna]

59 minutes ago, Radian said:

So that would soak the external brick leaf but how is it tracking across to the internal? It may be a cavity full of mortar snots or other rubble from when the house was built, it may be something else bridging the cavity. Has the cavity been filled with insulation?

Or do you see evidence of any ants in the vicinity. Ants have a penchant for gathering soil and transporting it to a void in which they construct a nest. Some species even favor a damp soil.

I believe that cavity wall insulation was installed several years ago.

[ToughButterCup]

Now's the time for a dig around in the inside wall, and floor boarding.

Get a damp meter and see just how damp (or otherwise ) it is.

Here's a link to a series of choices of damp meter. (I assume you haven't got one)

[Pollyanna]

On 31/05/2023 at 08:53, ToughButterCup said:

Now's the time for a dig around in the inside wall, and floor boarding.

Get a damp meter and see just how damp (or otherwise ) it is.

Here's a link to a series of choices of damp meter. (I assume you haven't got one)

Hi I will get one ordered up and come back to you in due course. Please bear with, and thanks for all your help so far!