New plasterboard damp (Plumbing leak?)

[Bankrobber]

Hi
I have recently stripped my kitchen and had a a new DPC injected into the walls. The Damp company then plasterboarded the walls using dot and dab, they said I would be able to decorate/fit a new kitchen after approx a week. Most of the plaster dried out ok, but after 3 weeks we still have damp patches on one exterior wall where the adhesive dabs are. Some of these appear to dry out and then become damp again, I have contacted the damp company who were unhelpful and said i needed to give it more time to dry out? I am now concerned although it is only 3 weeks as most of the new kitchen is fitted and the damp does not show any signs of drying out it just goes through cycles of appearing to start drying then getting damp again. The house is Victorian end terrace with solid brick walls.
Any advice would be most helpful.
Thanks

 

[JohnD]

injected dpcs do not have a good reputation, you need to find the source of damp and correct it. If as you say the patch is drying out then getting wet again, there must still be a source of damp.

do you know where the damp is coming from? In a kitchen common sources are:

leaking pipe (this can include a water main in a solid floor that has rusted and pin-holed)

sink drain

gutter dripping or downpipe leaking on other side of wall

sink overflow

washing machine etc

fractured gulley outside

dripping from bathroom above or leaky soil pipe including at joint in ground

excess condensation from unvented drier

rainwater penetrating round window or door frame

outdoor tap

have a look at the outside of the wall

if this is on a party wall then the source of damp can be next door.

 

[Bankrobber]

Hi
Thanks for the reply I have already checked outside and could find no obvious signs of any damp penetration. There are no pipes close to the damp patches other than a central heating boiler that has no signs of any leaks and the pipes come from the ceiling. There was a small hole around the flue, but i have filled this.

 

[JohnD]

is there a water pipe under the floor?

 

[Bankrobber]

The nearest source of underground water is where the soil pipe joins the underground drain, however there is no damp adjacent to this and this drains away from the house.
Is it possible that there is still moisture in the wall and this will eventually dry now the new DPC has been installed?

 

[JohnD]

it's possible, but you said it was drying out then going damp again

is it anything to do with wet or cool weather?

What route does the sink waste take? Where is thh washing machine?

Maybe you can post some pics inside and out to spark ideas.

Do you wet-mop or wash the kitchen floor?

What pets and small children do you have?

can you dig or drill a hole outside the wall and see how wet the ground is? And under the floor inside?

where does the cold water supply come into the kitchen? And what route does it take from the road? Is it damp under the other floors?

Is it a solid floor, or wooden with plenty of unchoked airbricks?

Have you looked at the gutter on a rainy day? Is there a yard gully? Where is the downpipe?

 

[Bankrobber]

The adhesive dabs can appear to dry during the day only to appear damp again in the morning (not related to rain but yes cooler tempratures). The sink, sink waste and water supply is on the other wall. The washing machine is adjacent to the damp but all plumbing has been renewed with no leaks. The floor is concrete and I have also removed all the ceramic tiles and no it does not appear damp. The washing machine is on this wall but all plumbing has been renewed and has no leaks. I have no pets but a five year old girl but she does not go near this wall. The down pipe is not on this wall. The yard gulley is on the other wall. Before removal, the old plaster touched the floor which I think was the main cause of the previous plaster becoming damp.
The exterior walls has been previously painted and this is flaking in some places but other walls have dried ok.
I will take some photos of interior & exterior, is it possible to post them on this site?

 

[JohnD]

//www.diynot.com/forums/viewtopic.php?t=129539

is the water main buried in the floor?

 

[Bankrobber]

Hpoefully I have loaded the photos correctly View media item 2956 View media item 2957 View media item 2958 View media item 2959 View media item 2960

 

[JohnD]

Is this damp above the worktop
View media item 2956
I think it is coming down from the bathroom above (edited: no. I am SURE)

View media item 2960
Is it a cavity wall?

stand back and take a wide view photo of the kitchen.

 

[Bankrobber]

Yes it is damp above the worktop.
Its a solid brick wall no cavity.
A internal or external picture?

 

[JohnD]

Internal.

if the condensate pipe from the boiler, or any other pipes are not visible in the pic, say where they are.

then go and have a look under the bath or take up the bathroom floor and I bet you will see a damp patch on the wall under one or more of the pipes.

If it is plastic (not iron) you will probably be able to replace it yourself fairly easily.

p.s. (this is just to upset you) how much did you pay for the injection damp-proofing?

 

[Bankrobber]

It is difficult to get a full pcture due to the size of the kitchen and doorway etc
Is the condenate pipe the flue? this comes directly out of the back of the boiler?
I cannot contemplate taking the bathroom floor at present the thought is making me feel ill, it was refitted only 6 moths ago and ceramic tiles laid.
Yes the damp proofing cost a fair bit, the surveyor diagnosed rising damp! Anyway the kitchen.......
View media item 2961

 

[JohnD]

aha! so the boiler is directly above the damp! Furthermore, the wall appears to be damp below the boiler, but not above it!

the staining looks to me as if there is no doubt that water is running down the wall (inside or on the surface)

you appear to have a modern condensing boiler. This condenses steam inside, which (is supposed to) run out of a pipe into a nearby drain. The boiler also obviously has a water supply, and pipes for the radiators and hot water.

So, in my view, the water is certainly coming from a plumbing leak, not rising damp, condensation or penetrating damp.

I say it is either running down from the boiler, or is from the bathroom. They are both above the wet spot.

Trace all the pipes you can and try to find the wet one. If that doesn't help, cut out a section of plasterboard, use a torch and a dry finger to trace it (it is fairly easy to repair the hole and fix the patch back for redecorating).

If the boiler is leaking, you may find it is losing pressure and needs to be topped up often. Check that the filling loop is turned off.

If you can't trace it, take photos of all the pipes round the boiler and in the bathroom and see if anyone can suggest more. The inner part of the flue will be quite steamy, but if this was leaking into the wall or room then you would have a severe and dangerous problem.

 

[Bankrobber]

Hi thanks
The boiler is a traditional boiler using HW tank etc. but does not appear to be topping up fropm the header tank regularly and was only recently serviced. Would they not detect a leak on a service? I was sure the boiler was not causing it.