New floor and now getting damp issues!

[dllive]

The windows/doors have been open (as much as I can) and its been 4 months since the plastered the walls with lime plaster. Its been boiling hot with only a few days of light rain in the intervening months.

Heres a photo:

You can see the discoloration. All the interior/exterior groundfloor walls have this dampness going up about 500mm.

Does that give you anything further to go on?

 

[Footsoldier888]

Are you 100% sure you are using the right paint? There is a good explanation of what sort of paint you need here:

http://cornishlime.co.uk/information/breathable-paints-explained/

It's good you have lime plaster though.

 

[Footsoldier888]

I know it looks bad but it can't be anything too major in that you have gone back to bare walls and lime plastered, which is the correct approach. The thing is it doesn't take much water to cause staining, just a few cupfulls.

If your paint is correct a common cause of damp like yours is the ground levels being too high on the outside walls. Or the walls are cement rendered with the moisture getting trapped behind. But hopefully these issues were addressed in your renovation.

 

[dllive]

Ive now had confirmation that they didnt use lime plaster(!) It was a gypsum one coat plaster. Is this a cause for concern? (Something tells me Im not going to like the answer). Just to clarify: the tide mark is on all external AND internal partition walls.

 

[Footsoldier888]

The trouble is that gypsum is not damp tolerant and modern houses have cavity walls to stop water getting anywhere near the inner leaf of the wall.

A photo of the outside walls would really help as to me at least that sounds like the more worrying problem. Why are these outer walls damp or even wet?

Sometimes it can be the drip channel under the window sills has worn away and when it rains water is getting fed onto the walls.

 

[JohnD]

. All the interior/exterior groundfloor walls have this dampness going up about 500mm.

So the ground or the floor is wet. It's a concrete floor, is it? Do you know that it has a DPM? Did you see it going in? Was it lapped up the walls and tucked behind the skirting? If the concrete floor is dry, then it's wet ground.

Are there any pipes in or under it, apart from the water supply pipe?

Have you got a water meter?

How old is the water supply pipe?

When were the drains renewed?

 

[dllive]

So the ground or the floor is wet. It's a concrete floor, is it?
Yes. Concrete/insulation/screed. All surveyed by a building controller. Before the concrete pour I walked around and the ground didnt feel/look damp (not that I was particularly looking). See below:

Do you know that it has a DPM? Did you see it going in? Was it lapped up the walls and tucked behind the skirting? If the concrete floor is dry, then it's wet ground.
I presume the DPM was laid (building controller oversaw this). I can currently see bits of green plastic appear above the screed, so I assume thats the DPM. Its not "lapped up the walls and tucked behind the skirting". The concrete is dry.

Are there any pipes in or under it, apart from the water supply pipe?
As far as I know there are no pipes under it or in it (apart from the under floor heating which I know is not the cause as it was pressure tested and commissioned last week). The water supply goes by the side of the house.

Have you got a water meter?
There was an existing leak when we first bought the house (Feb 2018) but this was detected and fixed in March. But as you can see form the photos - the ground looks dry(?)

How old is the water supply pipe?
As I say, the old water pipe was fixed and the builder has upgraded to a modern plastic pipe from the road to the rising main.

When were the drains renewed?
Drains are not under the house. I did have these inspected (they used a camera) and all was fine.

Ill try and take some video/more photos tomorrow of the outside walls and try and put it 'in context' for you. The builder/plasterer/everyone's saying "it will dry out once the UFH is on and theres warmth in the house" but Im not so sure (I hope to god Im proven wrong!). The plaster has been on for atleast 4 months and we've only had a handful of rainy days/nights, so surely it should have dried out by now! Unless its condensation which is forming the 'tide mark'.

 

[Footsoldier888]

Well it could yet all turn out well, perhaps it will dry out?

If it was me I would be a lot more concerned about the state of the outside walls if they are damp or even wet.

Perhaps you have a raised concrete path all round these walls and water is splashing above the damp course. Or the stone has been cement pointed and water is getting trapped in the stone.

Clearly this is a total renovation, did you tackle it from roof down so to speak and have a plan for the outside or whole building? I take it you had a full structural survey before starting this work, or a plan of works from an experienced builder?

 

[dllive]

Well it could yet all turn out well, perhaps it will dry out?

If it was me I would be a lot more concerned about the state of the outside walls if they are damp or even wet.

Perhaps you have a raised concrete path all round these walls and water is splashing above the damp course. Or the stone has been cement pointed and water is getting trapped in the stone.

Clearly this is a total renovation, did you tackle it from roof down so to speak and have a plan for the outside or whole building? I take it you had a full structural survey before starting this work, or a plan of works from an experienced builder?

Youre right, the ground to the right front of the house is further up the wall than I would like. (It seems at some point in the past they were overzealous with the gravel!). I will try and take some more photos of the outside. But surely that wouldnt create moisture on the internal pation walls. Ive got a dehumidifier going.
Thanks.

 

[Footsoldier888]

Yes you are right about the internal wall. As the other poster said, that could suggest a problem with the dpm not going up the walls by a good amount like in this short clip.

No dpm up the wall and plaster coming down to floor level could give you a problem like yours.

 

[JohnD]

the amount of water showing on the walls is very similar to what I saw in a house which had a burst pipe, and the solid floor was flooded with water for about a day. As it is on the interior walls as well as the external walls I believe you have a "wet ground" problem. A leaking pipe seems to me most likely but if you have disproved this (remember that old buildings can have old pipes that have been forgotten about) where is it coming from? The walls were wet even after a long dry spell.

 

[dllive]

The DPM doesnt go up the walls at all.

Ive taken some more photos. Hoping they shed a bit more light on the situation.

This is an internal wall. The 'tide mark' isnt a clean line - its blotchy. Not sure if that could be a sign of anything else (ie condensation):

Outside wall next to a fireplace. Shows damp pacthes emanating from fireplace:



Another internal wall:
Front left elevation. The ground level was almost to the window sill!! Even with my limited knowledge I knew that wasnt a good thing so we dug all that away. You cant see it in the photo, but at this level it unveiled a yellow french drain pipe. So basically someone in the past had laid a french drain and put ~600mm gravel on it(!)


Front right elevation. The gravel here is lower than what was on the left side. The gravel here is about the same level as the floor inside. Maybe that is still too high?



In the photos I posted in a previous post - the ground doesnt look damp does it? It was almost dusty from what I recall - and that was in February when it was cold/damp outside.

 

[Footsoldier888]

It looks a most interesting project.

I wouldn't say your problems are too bad outside but it is a shame it wasn't tackled first.

If you have to take the plaster off at this stage, in the scheme of things that is not a big expense compared to say finishing everything and then getting a bad damp problem.

I would have thought the area where the wall abuts the house and under the two windows needs the attention of a builder who understands and has worked on old buildings.

 

[Footsoldier888]

Given the lack of heating I take it this house has not been occupied for some time. All I am thinking is if you introduce a heating system, people and washing machines etc then if the house hasn't been tackled properly your problems could get worse at that stage. So the marks you see could turn out to be a blessing in disguise.

 

[dllive]

Im not sure what the next step is. Should I get a speciailist in? Who would be the best person (Ive heard some surveyors will automatically recommend a DPC which might not be the best solution in an old house). Im at my wit's end with this - I dont know who to turn to.