Damp / Condensation on Party wall

[KenGMac]

SALL2009, good evening again.

In no particular order.

Look at fitting a room vent into the blocked of chimney in the ground floor, provided the chimney stack checks out OK? and ensure there is a vented terminal on the pot.

As for the "dampness" between the wall paper and the plaster above the area of wet plaster on the ground floor? If it were me, I would strip the paper and wait, what can and does happen is that the dampness from lower levels, provided there is enough of it will "wick up" the interface of plaster and wall paper to cause damp marks to appear on the plaster, in a load of cases leave the wall paper of and allow the plaster to breath and dry.

The possibility of failed Cavity Retro-filled insulation, a whole different can of worms? I recall asking that question several reply's back?
At times what can happen is that the fill becomes saturated, the water gathers at the base of the wall? but in your case the presence of an un-vented chimney ??
As above, I would tend to play the waiting game, to see if the dampness dissapears as the property warms up or ??
As for how to proceed if indeed the cavity fill has failed?
A/. Find out who holds the insurance backed guarantee for this material, the vendors Solicitor [Lawyer] may have some info?
B/. Get the property surveyed for failed cavity fill, there is a vociferous small "industry" around this form of defect.

Ken.

 

[Leofric]

Apart from new work ,NHBC also cover conversion work eg barn conversions , and this can involve damp proofing existing solid brick walls by chemical injection. I worked for an NHBC registered housebuilder for 13 years and was dealing with NHBC every week on projects including conversion of old buildings into dwellings. Contact your local NHBC office and ask them if they cover conversion work including damp proofing of existing walls if you don't believe me. The damp proofing has to be carried out by an approved installer including ' replastering ' ( a term used by specialist firms themselves ) to their specification which forms part of the damp proofing process in order to be covered by their warranty.

p.s. this is a reply to bobasd's comments

 

[SALL2009]

SALL2009, good evening again.

In no particular order.

Look at fitting a room vent into the blocked of chimney in the ground floor, provided the chimney stack checks out OK? and ensure there is a vented terminal on the pot.

As for the "dampness" between the wall paper and the plaster above the area of wet plaster on the ground floor? If it were me, I would strip the paper and wait, what can and does happen is that the dampness from lower levels, provided there is enough of it will "wick up" the interface of plaster and wall paper to cause damp marks to appear on the plaster, in a load of cases leave the wall paper of and allow the plaster to breath and dry.

The possibility of failed Cavity Retro-filled insulation, a whole different can of worms? I recall asking that question several reply's back?
At times what can happen is that the fill becomes saturated, the water gathers at the base of the wall? but in your case the presence of an un-vented chimney ??
As above, I would tend to play the waiting game, to see if the dampness dissapears as the property warms up or ??
As for how to proceed if indeed the cavity fill has failed?
A/. Find out who holds the insurance backed guarantee for this material, the vendors Solicitor [Lawyer] may have some info?
B/. Get the property surveyed for failed cavity fill, there is a vociferous small "industry" around this form of defect.

Ken.

It has been a busy week or so, we took out all of the concrete (gone below the slate DPC) and then installed suspended floor. There is a step by the patio door which is half way up an air vent, so could explain one source of water. But still doesn't explain the area near the rad looking still wet?? Guess it is a waiting game now (waiting for plaster to dry).

Chimney stack seems to be fine. The roofer said the lead flashing looks perfect, The pot is covered and vent and thinks that some water maybe coming through (angled rain) but should dry out once the property is heated.

Managed to speak to the owner and she said there used to be the kitchen there and boiler back pipe use to run down there. When we dug, there were no clear signs of a source of the issue, i.e. soil was damp but no water. The owner also said that she had a survey done (to get re-finance) and they said there was no rising damp issue (just condensation caused an above floor level vent she has closed off). Also, according to her the neighbours have the same issue, but when I spoke to them, they said they don't have damp just a bit of condensation.

 

[SALL2009]

This is the patio door at around 12 pm, the bay window has similar amount of moisture on it. Does this seem excessive amount of moisture for the current weather and can explain plaster not drying out?

 

[JohnD]

had it been raining?

does the paving slope towards the house?

show us the outside, especially the gutters and downpipe

and the outdoor tap

All that water is coming from somewhere.

Show us the damp soil too.

 

[SALL2009]

It hasn't rained for around a week now, but prior to that it has been fairly wet weather. I only have this picture of the outside at the moment



That vent under the slab could be the source of water to enter, as on the inside the cavity was bridged and concreted above slate DPC with no membrane. (But i'm not sure that much water could come and spread from there?)

This is the soil after removing the top level of concrete.



This is wall two days after being plastered.



I was there today and the bricks below the plaster look dry.

This is a skimmed wall on the other side of the room (was dry and no damp issues) was still very patchy after 2 days. It seems mostly dry today (3rd day) after I kept the windows and doors open for good few hours.

 

[JohnD]

The paving slabs in your outdoor picture look very wet. Why?

There is a small trap in the paving, such as a stopcock or water meter would be underneath. What's down there?

 

[SALL2009]

It had been raining that day.

It's the water meter. When i opened the lid, there was water droplets on the meter and soil around it wet. not sure if that's normal?

The direction the pipe seems to be coming from, doesn't seem that it runs under the house.

 

[JohnD]

let's consider the possibility that the pipes connected to the meter are leaking. It is, after all, a water pipe of unknown age next to a wet patch.

Is the bubble turning?

Is there a stopcock in the pavement?

What route do you think the pipes take?

Are there pipes or tanks in the loft? Where do the pipes go? Where is the kitchen now, and where was it when the house was built?

Time to get your spade out and have a look.

An experienced plumber or waterman can listen to the pipes and hear if there is the hiss of a leak.

 

[SALL2009]

The meter was installed a year ago and the pipe (what i can see) look the new plastic pipes.

The didn't notice a bubble on the meter, i'll have another look.

No stopcock that i can see.

I think the main water pipes run under the gardens(for the street) and then a supply comes to each house.

I did a visual from the loft hatch and no tank in the loft and couldn't see any pipes either (but it is insulated so can't be sure).

The pinnacle of my artistic skills.



The meter. Ok, just noticed there is a stopcock next to the meter.

 

[JohnD]

looking at the diagram, I see the wet patch is along the wall of what used to be the kitchen.

It's possible that the cause of the water isn't an old leaking pipe.

But I wouldn't put money on it.

Spade time.

 

[arkie]

Are you still not living in it? Are you heating the house to 18c?

 

[SALL2009]

Are you still not living in it? Are you heating the house to 18c?

No still not living there.

Well in a bit of a catch 22 situation. To heat properly, I'll have to close the windows, doors etc, but to air the place I'm keeping windows and doors open when we are there.

 

[arkie]

If you cant have a window on a vent and heat it, You should probably buy a cheap dehumidifier or borrow / rent one.

And if you cant babysit it, set it up with a hose down the kitchen sink.

 

[JohnD]

I think you should ask @Ian H

he likes this sort of thing.