# Rising Damp?



## straas (7 Nov 2022)

When we first moved in (circa 9 years ago) I noticed brown stain type paint on the plaster by the front door that I assumed might be to do with rising damp.

I have noticed it getting a bit damp there when it rains but always put it to the back of my mind - the area of damp had now spread to the side wall and maybe 800mm off the floor, I did have the cavity wall ties renewed a year or two ago and wondered if this may somehow have made it worse? The wall has had lining paper installed and it's fairly obvious to see visually. It recedes when we have a dry day or two.

It's a job I keep meaning to get round to, but life gets in the way.

We've got a suspended timber floor and varnished floorboards, my idea at the moment is to carefully cut and lift the first few to give access to the wall, then drill the mortar and install Dryrods.

Has anyone done this before, and does it sound like a sensible approach?


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## fossyant (7 Nov 2022)

How's the house generally for damp ? Is a dehumidifier worth a shot if it's an older property ? Is it just on the surface ?


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## MichaelW2 (7 Nov 2022)

You need to inspect yourfloor timbers for rot and ensure good ventilation.


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## TissoT (7 Nov 2022)

I have used/fitted Dryrods they are Affective depends on how wet the wall is.


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## Ian H (7 Nov 2022)

Sounds more like penetrating damp than rising damp to me. If it's by a door it might be something around the frame. I assume the ground level outside is below the damp course. 
I have also seen problems caused by dirt having built up over years under a suspended floor, but that was an older house.


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## ColinJ (7 Nov 2022)

Ian H said:


> I have also seen problems caused by dirt having built up over years under a suspended floor, but that was an older house.


That happened to the house that my niece bought in Exmouth. She discovered that the floor was rotten and had to be replaced.


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## straas (7 Nov 2022)

fossyant said:


> How's the house generally for damp ? Is a dehumidifier worth a shot if it's an older property ? Is it just on the surface ?



The rest of the house is generally ok, we run a dehumidifier for drying clothes.

If I put the dehumidifier by the damp it doesnt drop below 73%

In other rooms it starts around 70% and drops to 50%

I do find it strange that it has such a strong response to rain - I've watched the gutters etc in the rain and can't see anywhere it's splashing onto the brickwork. Also the exterior brickwork doesn't show signs of damp.


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## berty bassett (7 Nov 2022)

Another one for water ingress here ! Sounds like rain is getting in somewhere more than rising damp to me - mastic on frame ?


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## straas (7 Nov 2022)

Interesting - so the dryrods could be a waste of time if so?

Few photos attached to show inside / outside. Cavity walls that were filled with those polystyrene balls before we bought the house.


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## TissoT (7 Nov 2022)

From a builder's point of view I would be inclined to check the condition of the rainwater drain.


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## straas (7 Nov 2022)

Thanks - I'm guessing you mean below ground level?

I did try to look previously but the grate is either glued or rusted in place


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## TissoT (7 Nov 2022)

straas said:


> Thanks - I'm guessing you mean below ground level?
> 
> I did try to look previously but the grate is either glued or rusted in place



Yes below ground. 

lift a few boards and take a look inside the sub floor to see what's going on.


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## the snail (7 Nov 2022)

I agree with the other posters it looks like rainwater penetration, rising damp doesn't usually look that wet, usually you see brown staining and/or salt crystals. My guess would be poorly sealed door/window, gaps in pointing or failed guttering/downpipe as others suggest. It might be worth going outside when it's raining and having a look.


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## Broadside (7 Nov 2022)

Is that a blocked up air brick to the right of the front door?


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## straas (7 Nov 2022)

Broadside said:


> Is that a blocked up air brick to the right of the front door?



It's got stainless mesh over it to keep mice out - little sods.


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## Ian H (7 Nov 2022)

Water can track for a long way before it shows itself, but generally downwards, not upwards. I'd be checking above windows & doors (lintels - anywhere where the inner & outer walls join) and even looking to see if there are any missing tiles or slates letting water into the cavity.


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## straas (7 Nov 2022)

Cheers all - I'll get the ladders out and see about cutting a floorboard.

Penetrating sounds less stressful that retrofitting a damp proof course.


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## postman (7 Nov 2022)

Got the same problem with a wall inside the corridor I am painting for the church ⛪.Ours will be dealt with when we get some real cash together.Two coats of damp proof paint hopefully will hold it back long enough.


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## straas (7 Nov 2022)

postman said:


> Got the same problem with a wall inside the corridor I am painting for the church ⛪.Ours will be dealt with when we get some real cash together.Two coats of damp proof paint hopefully will hold it back long enough.



Let me know if you get the cash - I need some too!


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## Gillstay (7 Nov 2022)

straas said:


> Cheers all - I'll get the ladders out and see about cutting a floorboard.
> 
> Penetrating sounds less stressful that retrofitting a damp proof course.



I once had to treat rising damp in a similar situation and just treating the cement between the bricks was enough.

I did it on a hot day so it got sucked well into the cement and did the worse bit by injection and the rest with a brush. 

Cured the problem, so must have been an odd spot causing the damp.


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## berty bassett (7 Nov 2022)

you little tinker ! you didn't say there was a rainwater pipe - when its raining go outside and watch what is happening - might be blocked anywhere and running onto brickwork - you could even run hose pipe in gutter to check - that picture isn't rising damp - its water getting in from somewhere that outside corner looks soaked


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## dave r (7 Nov 2022)

ColinJ said:


> That happened to the house that my niece bought in Exmouth. She discovered that the floor was rotten and had to be replaced.



We had similar in our first house and I had to replace most of the joists, it had a sleeper wall going across the middle of the room, I had to cut off the rotten joists in front of the sleeper wall and fit replacement joists that extended behind the wall, I always thought the TV rocked because of the cheap stand it was on but it was the floor.


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## ColinJ (7 Nov 2022)

dave r said:


> We had similar in our first house and I had to replace most of the joists, it had a sleeper wall going across the middle of the room, I had to cut off the rotten joists in front of the sleeper wall and fit replacement joists that extended behind the wall, I always thought the TV rocked because of the cheap stand it was on but it was the floor.



The house in Exmouth had a faulty drainpipe which was leaking water onto the front wall of the house. It had probably been like that for years. The water was running down the wall into a crack and getting into the soil under the floorboards that way.


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## Slick (7 Nov 2022)

Obviously I could be very wrong but I reckon the fact you replaced the wall ties could be significant as they form a bridge between the inner and outer skin of the house. Cavity wall insulation won't help, even if it is the balls. Houses were built with a cavity for a reason.


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## dave r (7 Nov 2022)

ColinJ said:


> The house in Exmouth had a faulty drainpipe which was leaking water onto the front wall of the house. It had probably been like that for years. The water was running down the wall into a crack and getting into the soil under the floorboards that way.



The house had been empty for several years, an old lady had been living there on her own and after she passed away the family was selling the house which had rising damp and several other problems which they had to fix before we brought the house.


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## CXRAndy (8 Nov 2022)

straas said:


> Interesting - so the dryrods could be a waste of time if so?
> 
> Few photos attached to show inside / outside. Cavity walls that were filled with those polystyrene balls before we bought the house.
> 
> ...



The air brick has been blocked, but also the gutter down pipe looks like it discharges onto the tarmac. The gutter gulley looks blocked too. I suspect water rising up from the gulley or tarmac areas.

Clean out the gulley, put an inspection camera down it to make sure it's not cracked. If it's cracked, dig out and replace with new.


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## straas (9 Nov 2022)

CXRAndy said:


> The air brick has been blocked, but also the gutter down pipe looks like it discharges onto the tarmac. The gutter gulley looks blocked too. I suspect water rising up from the gulley or tarmac areas.
> 
> Clean out the gulley, put an inspection camera down it to make sure it's not cracked. If it's cracked, dig out and replace with new.



It's just a stainless mesh on the airbrick - reduced flow but not blocked.

The downpipe outfalls into the drain - it's not blocked, stainless mesh to stop the leaves getting down, I tip into the green bin regularly.

I've just ordered a borescope from amazon - should be here tomorrow.


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## MrGrumpy (11 Nov 2022)

We had an issue with dampness and water ingress, when we moved into this house . 
It’s modern but it took my nearly a year to work out what was going on when it was heavy rain. Water coming up through skirting and water running down inside of front window . 
It turned out to be a gap at the concrete top lintel outside , the lead flashing didn’t come all the way along and there was a hole. 
Mixed up some mortar and filled the gap . No more water and the wall inside above the windows is now dry . The plaster was damp and flaking .


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