Wet bricks after plaster removed

[Springmachine]

Hi, I had a leak in the kitchen which means the floor was soaked and has been ripped up. The plaster was slightly blown in a patch next to the worst of the leak and was pulled off at the same time.

It's an old house circa 1900's and there was 3 layers of plaster removed.

Underneath has revealed quite damp looking bricks.
More damp than I imagined they should be after the leak.

What would be the best action here?
The insurance company dealing with the leak drying have stripped out and put dehumidifiers in but not too sure this is enough to sort this wall?

We changed guttering when we moved in as it was faulty to the outside of this wall so maybe that has something to do with it but that's 18months ago now.

At some point we need to replaster and decorate and to prevent any future issues want to put some sort of breathable membrane in. Would that help?

You need to find the source of the damp and fix that. Otherwise you are just treating the symptoms, not the cause. Where the gap is, what is in there? If there is rubble, etc it needs to be removed or it means damp from outside can travel through the cavity between the two walls. You can probably reach inside the cavity with a phone in your hand and take some photos with the flash on.

The cavity is soil stack and plumbing to upstairs. It's totally dry in there.

The house had issue with a leak previously in the same place about 2 years ago but that's been fixed.
On top of that the same wall had got damp due to faulty guttering which was then also fixed.

The outside ground levels are low, the guttering good and the pipe work is all sealed.

Surly it can't still be wet from before?

is it a concrete floor?

have you got a water meter?

How close is the wet patch to the place where the kitchen sink was, when the house was built, and where the water pipe comes up through the floor, and where the waste pipe goes through the wall to the gulley?

@PigletJohn

It is a concrete screed floor, we do have a water meter (newly installed)
The wall is located on the wall near to wear a sink once would have been.

There are pipes in that wall but they are all visible within the void

I've just been watching my water meter and it's steady at the same number

The concrete floor next to the wall doesn't appear damp despite our recent dishwasher leak

have a look at the water meter. Is there a glass window with the a bubble in it? The bubble moves when water is flowing. Does yours ever stop? It is much more sensitive than the numbers.

Doesn't seem to be moving at all.
We had trace and access 18 months ago so all pipework has been tested not so long ago and we had a new water main installed so none of the original old (leaky) pipework from when the house was built is in use anymore

that's good.

Water can move up a plastered wall by capillary action, sometimes by a metre or so. An unplastered wall (both sides) it rarely moves up by more than a couple of bricks above ground level, due to a peculiarity of capillarity stopping because the pores in the brick are not the same size as the pores in the mortar. A wet wall can take a year to dry out, much longer if the bricks are not exposed to dry air. Blowing a fan on the bare brick will help dry it out, the movong air takes up the water, and the dehumidifier dries the air. Dehumidifiers warm the room a little as well. Take your electricity meter readings before and after they are used, the insurance co will pay for the estimated usage.

If the ground is wet, water will be absorbed into the wall from below. Now the plaster has been hacked off, it should be able to dry out.

If you tape a piece of clear plastic to the floor, see if the concrete turns wet beneath it. It may look dry if water is evaporating off the surface faster than it penetrates from below.

Your concrete floor looks quite old and cracked, one day you could have it dug out and a new one laid, with DPM and insulation. This will be a good time to examine any pipes and drains in the floor, and perhaps renew them. Old water pipes often leak between te ages of 50 and 100 years. Old clay drain pipes usually are cracked and leak at the joints, traps and bends if they were laid before May 1945 and you are in or near a town or city.

Sinks often leak into the floor without being noticed, and washing machines sometimes do.

Try to resist chemical treatments or waterproof plastering systems. They hide damp but do not cure the source of water (which is usually a leak or a building defect).

@PigletJohn thank you

I'm inclined not to put any special treatments as it looks like people have done this in the past and it might have just held all moisture in. It was 3 layers thick. Hoping it dries soon.
It doesn't feel that wet to the touch it just looks wet from the colour and slight smell.

How quickly with the dehumidifier and blower going should it dry now?

maybe a month.

Thank goodness, I was worried you were going to say a year!

I'd have to find my diary notes from a previous job, but I remember the walls with blowers dried and were replastered, but the pantry had a wet wall after several months where there were cupboards in front of it that had not been removed. We pulled the cupboard out and put a big blower on it 24/7. I don't really remember how long it took. it was noticed because a socket in the wall was shorting out and damaged the cable.

The difference after just a few days is noticeable so we are going on the right direction at least. I'm taking regular photos to keep track. Looks a lot better... (before and after 'today' shot)

Here is a photo from last week. At this point we had been tuning dehumidifiers for a few weeks constantly.

However, after 2 days of them not being here anymore the wall looks a little more damp again.

I've checked my water meter again and can't see any sign of movement.

Am I missing anything else before I get damp proofing specialist over?

Ps - multiple surveyors have checker externally and confirmed no penetration of eater there

It looks as though there's a leaking pipe somewhere or a watercourse of some description. Is your house detached or are you attached to any other houses? It could be a leak on another supply for example.

It could be a waste water pipe or drain leaking.

It's not attached on that side.
There is a water pipe that leads from the mains entry to the point it goes upstairs along the base of that wall under the concrete screed.

I looked at my water meter and it's not moving at all but I'm now thinking it could be ever so slow that I wouldn't see it.

This has always been a problem wall and the pipework in that section is anywhere between 50-100 years potentially.

No waste water pipe that side, main drain line location externally is a few feet from that wall and been checked before we moved in.

My money's on a leaking pipe and I'd get the pipework in that area replaced.

Thank you @wowfudge

Would I need to dig up and expose the original pipe or could I potentially cap off at either end and put reroute a replacement ?

This is the visible part of the pipe where it exits to return to feed upstairs

I don't know - that photo looks like it could be copper pipe fitted onto lead and old lead may well have sprung a leak.

Over the past few days I have been getting people in to take a look. Im more confused than ever as every person says something else.
Overall the advise has been:

From the damp specialist -
The wall will never dry, its an old house, tank it.

From the general builder -
Scratched his head at wondering if it could be a very slow leak or if its something else. Confirmed external wall was sound and no moisture coming in from outside.
Said the house didnt have a damp course so he would suggest injecting wall with chemical damp course and redoing the screed with a dpm.

From the heritage surveyor -
Do not tank it. its just wet and still drying out. The dehumidifiers only did a job of drying the top surface of bricks, now they are gone its just the internal moisture still finding its way out. It; take a long time to dry properly. Said that the house wasn't built with a damp course as that age of house isnt, but thats nothing to worry about and rising damp is very rare. The house is built in an area where the ground water levels are low. The weather has been dry so the moisture isn't coming from the ground or outside in their opinion.

Another general builder:
The concrete floor used to have a bitumin coat to the surface which has been removed. Recoat it with liquid dpm and put some up the wall. Stud and dryline and then skim.