Damp

[Outonmyear]

Hello all, hoping somebody can help me. About to buy a house in great location with loads of potential. Priced fairly as it needs a lot of updating. Survey just come back as red for internal and external damp 😱
I’m not the calmest person about damp so no idea what to do next. Surveyor said some could be explained by cracked render (but that one wall was suspicious in that it had been replastered and painted fairly recently)
His biggest concern was this - on an internal wall between living room and dining room. Is this definitely rising damp?

@PigletJohn Would appreciate your advice on this one. Just been reading some threads where you have given amazing insight. Your thoughts would be very welcome 🙏

If there are no pipes in that area that might be leaking then it’s got to be coming up the brickwork from the ground . How old is the house ?

Suspended wooden floors or concrete slab?

@Outonmyear

Hello all, hoping somebody can help me. About to buy a house in great location with loads of potential. Priced fairly as it needs a lot of updating. Survey just come back as red for internal and external damp 😱 I’m not the calmest person about damp so no idea what to do next. Surveyor said some could be explained by cracked render (but that one wall was suspicious in that it had been replastered and painted fairly recently) His biggest concern was this - on an internal wall between living room and dining room. Is this definitely rising damp?

looks to me like there is a source of water, most likely a plumbing leak, in or close to that corner.

Is the floor concrete?

Where is the bathroom?

Where was the kitchen when the house was built?

What is on the other side of the wall?

How far away are the radiator pipes?

Thank you so much.
1930s house. Bitumen damp proof but solid floor. Chimney breast on opposite wall will need venting as all chimneys have been blocked without vents.
Surveyor thought damp proof may have failed but had no real suggestions about this one.
There potentially may be a central heating around there I suppose but not sure at all.

Nothing obvious above which could be trickling down although conceivable there may be central heating pipes.

Didn’t see above messages before replying. Thank you both.

Surveyor said solid floor - so concrete? Was assuming a suspended floor in a 1930s house so little surprised. Kitchen well away at back of house. Bathroom a distance away too. Kitchen was possibly in the morning room which backs on to this corner when built. There is also a dining room other side. No idea on configuration of central heating pipes.
Surveyor seemed to suggest damp everywhere which was a bit alarming some of which the vendor has tried to hide by replastering.

I’ve always thought of damp as sinister and incurable so I’m in a right tizz but love the house and think it will be worth it. Thank you all for helping me to see it as a rational thing!

@PigletJohn
Please excuse this very amateur picture which is not to scale! Circled cross is damp I showed a picture. Other crosses are other spots of damp he found and said outside bricks are damp too? Presuming cavity wall construction 🙏

the wet patch appears to be mountain shaped, so probably not generalised dampness, but a particular water source near the point of the peak.

a leaking pipe in the concrete floor is common.

or a pipe buried in the wall with a leak where the point is

or a bath on the other side of the wall with a defect in the tiling or bath sealant. It does look very localised. If the bathroom is above there might be a pipe hidden in the wall.

it looks too pointy to be a drain leak, unless there is a fault in the wall allowing water to track through.

if the walls have previously been tanked or treated then they might be damp, but hidden.

why do you assume cavity? 1930's house often solid. Have you got any pics showing the outside brickwork pattern?

Is there any sign of rows of holes drilled in the bricks near ground level, in a futile attempt to repair faults by injecting silicone?

Is this a terraced house with external walls only at back and front? Damp internal walls are pretty sure to be plumbing.

if you can get back, or study your pictures, look for the outside stopcock, usually next to where the front door used to be when the house was built; and the indoor stopcock, under where the sink used to be when the house was built.

the incoming water service pipe is pretty sure to be in a straight line between them, and quite likely to leaking at this age. a leak in a concrete floor can cause no end of damp, you will see it if you lift floor coverings.

Look at the outside walls for any signs of airbricks, which would indicate the house was built with wooden floors.

@PigletJohn

why do you assume cavity? 1930's house often solid. Have you got any pics showing the outside brickwork pattern?

Is there any sign of rows of holes drilled in the bricks near ground level, in a futile attempt to repair faults by injecting silicone?

Is this a terraced house with external walls only at back and front? Damp internal walls are pretty sure to be plumbing.

if you can get back, or study your pictures, look for the outside stopcock, usually next to where the front door used to be when the house was built; and the indoor stopcock, under where the sink used to be when the house was built.

the incoming water service pipe is pretty sure to be in a straight line between them, and quite likely to leaking at this age. a leak in a concrete floor can cause no end of damp, you will see it if you lift floor coverings.

Look at the outside walls for any signs of airbricks, which would indicate the house was built with wooden floors.

Thank you. This is all amazing.

It’s a semi detached house with pebble dashing. No sign of airbricks at ground level. Didn’t see any dpc holes in render. I don’t know why I assumed a cavity.
Annoyingly the surveyor said he couldn’t find the stopcock apart from one on the street.

Looking at the estate agents floor plan that damp patch is nearly on a straight line with the sink if you trace towards the front door.

I’ve put a cropped photo of the side of the house to show pipes etc. Thanks again.

I have some internal walls EXACTLY the same as your pic....I assume rising damp. Does not cause me any issues, so I live with it. On other walls with the problem, I re-plastered with 'Limelight' renovating plaster (up to a height of about 3 feet), which solved the problem (though it's a messy job, and takes a few days,
as 3 coats required).

it looks to me like the ground level round the house has been raised by the paving, and quite likely has bridged the original DPC. You might be able to see it under or beside the front or back doorstep, or, if you look at other houses in the street, you might be able to gauge where ground level used to be, and possibly see the dpc.

Looking at the gable end wall, I see three drain/soil/downpipes.
In a 1930's house these are pretty sure to join to brown salt-glazed clay sockets or gullies in the ground, which are pretty sure to have been cracked and started leaking around 1941 if the house is in a town or city, or near a factory, waterworks, gasworks, railway terminal, marshalling yard, warehouses or harbour.

Does it seem to you that the other damp patches correspond to the positions of these drains?

@tanguero

I have some internal walls EXACTLY the same as your pic....I assume rising damp. Does not cause me any issues, so I live with it. On other walls with the problem, I re-plastered with 'Limelight' renovating plaster (up to a height of about 3 feet), which solved the problem (though it's a messy job, and takes a few days, as 3 coats required).

Will take a look at that plaster, thanks. Do any of these ideas explain your damp wall?

No, there's no leaks or water ingress, just damp rising up the bottom of the walls (1917 house) by capillary action. With 'Limelight' (or other lime based plaster), the water (I presume) still rises, but the plaster doesn't hold it, just allows it to 'wick' into the air. The lime plaster walls are dry to the touch, with no visible water mark - though the paint tends to flake off the wall bottom in patches (I presume because of the water finding its way out of the wall). THIS CAN BE SOLVED by using breathable emulsion such as 'Earthborn clay paint'. (I used normal Dulux).

@tanguero

"there's no leaks or water ingress, just damp rising up the bottom of the walls "

damp is water.

where do you think yours is coming from?

@PigletJohn

it looks to me like the ground level round the house has been raised by the paving, and quite likely has bridged the original DPC. You might be able to see it under or beside the front or back doorstep, or, if you look at other houses in the street, you might be able to gauge where ground level used to be, and possibly see the dpc.

Looking at the gable end wall, I see three drain/soil/downpipes.
In a 1930's house these are pretty sure to join to brown salt-glazed clay sockets or gullies in the ground, which are pretty sure to have been cracked and started leaking around 1941 if the house is in a town or city, or near a factory, waterworks, gasworks, railway terminal, marshalling yard, warehouses or harbour.

Does it seem to you that the other damp patches correspond to the positions of these drains?

Removed my own message in case pic IDd the house.

There are some patches on the carpet in the morning room which could be damp/ could be just staining. Seems to correspond with that damp area though.

Other damp patches could be caused by the pipes outside or breached dpc.

Is replacing water main under house or replacing clay joins really expensive?

not really. a sturdy woman who knows how to drive a spade can do most of it. Plumbers are weedy little fellows with petal-soft hands so a small local builder or labourer usually does it.

The new pipe does not have to follow the same path under the house.

In your case, as you are end of terrace, it could sensibly be trenched to the side of the house, and enter through the kitchen floor.

The old pipe was quite likely 1/2" ID nominal, which is fairly small but adequate for topping up a loft tank. modern practice is to run a plastic pipe of 25mm or 32mm OD which will give much better flow, sufficient for a decent shower from a combi or a powerful one from an unvented cylinder, and will fill a bath in reasonable time. Ample flow should prevent the squeals of annoyance from someone in a shower when a tap is used elsewhere in the house.

i think your supply pipe is probably iron, but if there is any possibility that the house has lead pipes, ask the water co to test the drinking water for lead content, which is harmful. They may offer a lead replacement subsidy or at least free reconnection to the main. Also ask if they have a leaking pipe replacement scheme. They might connect free if you get a water meter and the new pipe is already in position ready to connect. They will want to inspect it before the trench is filled in to ensure it is at the correct depth. If you have a plumber, ensure they fit full-bore stopcocks at the boundary and inside the house. They are more expensive, but will not impede flow. It is a hundred times more effort and expense to replace stopcocks afterwards, than at the time of laying.

If, as I suspect, the clay drains are cracked and leaking, this is again work for a small local builder, though it is quite a pleasant outdoor DIY job in summer. Look out for wild tomato plants or red worms in the soil which are signs of broken sewers and soilpipes. When reinstating you can lower the ground against the house, or fill the trench with cobbles and pebbles which do not allow water to rise by capillarity. All this can be done in one job.

You mention damp patches on the carpet.
This is consistent with a water leak in the solid floor.

Is there a water meter?

An experienced wrinkly old plumber can confirm a leaking pipe in other ways. It is common.

Thank you @PigletJohn you’ve made everything seem manageable rather than utterly terrifying. 🙏

I’ve spoken to someone on same road who has had ‘moling’?? Done with the water pipe too. My husband is wondering why I am scrutinising the paving level against the house on street view 😂

I’ve found a damp surveying company who seem like they know what they are doing but don’t know whether to bother with another survey or just accept it’s part of getting a house 30/ £40k lower than some of the neighbouring ones. I’ll sound out the estate agent/solicitor.

No idea about water meter, I’ll go and read the survey for the 75th time.

don't allow anybody who sells silicone injections near your house.

@PigletJohn

don't allow anybody who sells silicone injections near your house.

That's scuppered my breast augmentation plan then...