Damp course help

[dunny]

Hi all,

I have a damp issue in the majority of the walls in my old (1896) house and asked a company some time back to come and install a damp course. They came along and did as requested and installed one of the modern cream based damp courses. This is the only bit they did, i.e. they didn't hack the plaster off, I did, and they didn't replaster.

I had one room replastered and stupidly, in hindsight, I asked the plasterer to take the plaster all the way to the floor so it would be easy to fit the skirts. The plaster appeared to dry out so we decorated (without the skirts temporarily) and after a short time all of the paper peeled off.

I asked the damp man to come back in and he basically said I have bridged the damp as with the damp course he installed the very bottom course will always stay wet. I had assumed the bottom course would be dry but happy to accept my mistake if that is the case - could anyone please confirm?

I have lost some confidence in the integrity of the damp course now and was therefore thinking I might double up and srill the first course and inject with DPC fluid - is there any reason why I shouldn't do this??

Having hacked off the plaster yesterday where it has bridged the damp I am assuming it should dry out but I am concerned as it was very wet in places. Even in places where the bottom couple of courses had been tanked - I thought tanking itself was waterproof??

Thanks

D

 

[JohnD]

Chemical treatments don't repair the source of damp.

In your house, does the water come from a leaking pipe? A spilling gutter? Puddles against the wall? Banked earth?

Once you have diagnosed and repaired the building fault that the water is coming from, the damp will dry out.

Post some pics inside and out please.

 

[dunny]

Hi

the damp is on all walls including the interior walls. No banked earth or water leaks it is just rising - this was confirmed by the previous damp guys. The outside is red stock brick sat on a sandstone plinth, the inside is just standard old brick. I will post some photos when I get chance, just hacking the rest off as we speak. Is there any reason why I shouldn’t inject on the course beneath where the cream based damp was installed? I am confused as to why bridging the bottom course in a wall that had the two bottom courses already tanked would allow the damp to track up?

 

[dunny]

Some photos

 

[dontbelieveawordofit]

looks like you have timber suspended floors. you need to make sure theres no leaks or water running into the floor under the house.
make sure there’s maximum ventilation under the floors from outside , as thats the best preventitive measure to start with.
in brick walls like yours with a sound mortar bed, modern dpc cream installed correctly should stop damp travelling upwards through the mortar bed . that’s what it’s designed for , and yes it works.
it’s a waste of time in loose rubble filled stone walls.
I’d suggest the dampness on the tanked area is likely condensation.

 

[dunny]

Thanks.

And is there any reason why I can’t damp proof the course above or below by drilling and pumping? Incidentally this is the only timber floor in the house and it does have good ventilation.

I haven’t plastered any of the other walls yet so I could go around and inject them all in addition to the cream that was applied.

D

 

[dontbelieveawordofit]

inject the lowest course .

 

[JohnD]

have you looked under the floor?

the concrete paving against the wall is obviously damp and green. Does it slope away from the house? Is water dripping onto it from the gutters? Show us the downpipes and drains that go into the ground near the house please, especially gullies. If they are clay they are pretty sure to be cracked and leaking. Look for any signs of cracking, sinking or patched repairs around them.

Can you work out where the external ground level used to be before the paving was added?

Show us the airbricks please.

Have you got a water meter?

 

[dunny]

Thanks John

The concrete does slope away and is in fact already about 9 inches lower than the internal floor - if you look at the pic with the sandstone in it the top is about level with the first course of brick on the internal. There is no water dripping onto it - also bear in mind ALL walls are damp including the internal walls. As I look around the otside of the house the internal floor level is about 10 inches or so above any of the outside levels. Under the wooden floor is in really good nick and all of the joist ends look good - they are sat on a DPC on a dwarf wall in most places.

When the DPC guy came he checked all of the levels etc and the remedial action was to inject cream into the bed on top of the first course all the way around the house. It may well be that this is all down to my mistake in asking the plasterer to plaster pretty much all the way down to the floor.

I have obviously chopped all of that back now and tanked the bottome 2 courses on all the walls in the room. I am just worried that if I just assume that it is fixed then I could be throwing goo money after bad.

I havent got a weter meter.

Will post some further pics tomorrow if I can.

D

 

[JohnD]

you can space the skirting off the wall on battens of (near as you can) the same thickness as the plaster, with the top one level with the top of the skirting. You will have a little filling to do and can probably fill the plaster against the battens before fixing the skirting. If you fix the battens in advance, a plasterer can work down to them for a neat edge.

the battens may get damp so I'd treat them with wood preserver after drilling the screw-holes. I suppose you could isolate them from the wall with thin strips of DPC. You can leave a bit of a gap between floor and skirting for ventilation. Normally I'd pack it to prevent draughts, but in your case I think ventilation will do more good. I wouldn't final-fix it until the wall seems fairly dry. To fix skirting to good battens only needs a few small countersunk screws. Stainless to avoid rust stains. In your case the lower batten should be spaced of the floor and have gaps. It is very easy to take the skirting off to check the wall by removing the small countersunk or raised screws, with no damage except perhaps paint over the screw heads.

I wonder where the water is coming from? Leaks are very common but it might be groundwater (should show under the floor).