TANKING OR DPC

[surreygirl]

Which is best. I have had a builder in and he said tanking would be fine. As stated in the other post my neighbour will not respond to a party wall notice so I cannot use a DPC on that wall so I thought I would have it replaster with Sika!

I am uploading photographs from the other thread which has been locked so I cannot upload them on/in to that thread!

 

[surreygirl]

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JohnD wrote:
you live in a basement so you might have penetrating damp and you probably have condensation. Show us some pics //www.diynot.com/forums/viewtopic.php?t=129539


I can see the photo's over the top but not in my post John!!

 

[JohnD]

I think your original post was
//www.diynot.com/forums/viewtopic.php?p=2459444#2459444

"Damp in Basement"

Is that right?

where you said

Well I have been told that I have rising damp in my flat which is a basement flat. I had a DPC put in about 20 years ago but it seems to have failed as I have damp coming up over the top of the DPC it is shown by red discoloration coming through the plaster and also on another internal wall the plaster is bubbling up. I can understand that the external walls could have water coming through from the outside but I do not understand why the internal walls are showing damp.

Also I have had some of the companies say I have damp in the bathroom and kitchen whilst others say there is no damp there!!

Others have said that I have a real problem whilst others have said that it is really only cosmetic and that the damp is not bad. Who to believe and what to do. Do I go for another expensive damp course or leave it and just replaster. Any advice would be appreciated

It doesn't look locked to me. If it is, click on "Alert Moderators" and ask for it to be released.

The pics are all a bit close, can you stand back a bit for a wider view, and put something in the pic like a hand or a cat or a 50p piece to show the scale?

Where the wall is very lumpy it puts me in mind of a Victorian house with lime plaster that has been whitewashed or distempered and then painted over the top. Do the blisters pick off easily?

In one of your pics I see a brass stop-cock. Wet walls next to pipes and taps are very often due to leaks.

 

[surreygirl]

OK I will do that John. Yes the loo has been leaking and also there was condensation from the shower.

The areas are small however the bubbling up is all over that one internal wall. It was all replastered in 1989 when I had the first damp proof course put in so it is not lime although I know what you mean!

Apart from that the areas affected are small but lots of them. But in the bathroom and kitchen the tanking seems fine.

 

[surreygirl]

I have managed to take some more photo's and will now see if I can upload them

Thank's so much for your help John I honestly dont know whether I am coming or going with all this damp proofing, membrane or tank situation

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The one on the end is another internal wall. That is the handle of the hoover to give some idea. Just appears that damp is coming over the top of the damp proofing that I had done 20 years ago!

The other thread was looked it said "this thread has been locked" not sure why. I am not very experienced at these things lol!

 

[JohnD]

I was particularly interested in picture 3.

The plaster looks OK until a few inches above the windowsill.

Has that section been replastered or tanked? What is on the otherr side of that wall (is there a source of damp such as wet earth, leaking gutter?)

picture 4 seems to have a similar line.

 

[surreygirl]

Yes I had a damp proof course put in years ago and below that the plaster is fine. What the surveyor said is that the damp has risen above the original damp course!

You can see the window and possibly water has come in through the wooden pane but that doesnt account for the rest of the flat ie the two internal walls. The tanking in the kitchen and bathroom seems to be fine even though the surveyor said it had rising damp too but he put his meter right above the cistern which had been flowing over. I have removed the tiles etc and the bathroom is drying out. The floor was also wet from the drain which gets blocked and brings water back in. I have had that cleared.

I didnt trust the surveyor's report as he was more interested in telling me to sell it (as it was ie needing a DPC because he said there were plenty of people who would buy it in its present state!) then in doing a damp proof survey and his report is all about selling it. His first words to me when he came in was "what a horrid little flat get rid of it!) He also stated that he could not see any evidence of a chemical injections and my understanding of that is that he can only tell if it was chemically injected by taking a sample!

Some of the companies I had in only found a small amount of damp others went straight through it and came up with every area needing a new DPC which is why I am so confused with everything!

 

[JohnD]

If you bring someone into your house from a company that sells damp-proofing, you can rely on them telling you you need to buy damp-proofing.

Correcting the leaks and ventilating to dry out will do a lot of good. Do you get a lot of condensation on the windows? If you tape a piece of clear plastic tightly to the wall you will see if water droplets form behind it.

I am still interested in the idea that the new plastering looks OK but the old plaster looks rough and blistered. Does it seem to you that the new is drier than the old? Was it done with a water-repellend sand and cement mix?

We may find a plasterer has something to say.

 

[surreygirl]

Hi John It was all plastered at the same time but as you can see from the photo's where there has been a DPC and the room has been tanked up to a hieight of one metre, all that area is OK it is the plaster above the tanking or water proof plaster which is blistering.

It does need to be re-plastered but should I put in a DPC or just tank up to the ceiling!

I cannot put in a DPC in the party wall as the next door owner has not responded to my "party wall noticce"

Thank you for taking the trouble to help me out. I am in a complete muddle about it all

 

[JohnD]

well it looks to me as if the tanking has worked, but I am no expert on that.

most of my experience with damp in houses has been caused by condensation, followed by leaks, and is cured by removing the cause and ventilating.

it might be interesting to see some pics of the outside of the walls, in case that sparks any ideas.

 

[peaps2]

It's the tanking and plaster that's causing the problem.

 

[surreygirl]

Those walls in the photographs are internal John! There is only the bit by the window which is external although I suspect that the outside walls are not water proof and need to be repainted!

 

[peaps2]

The walls will have been lime rendered originally, some are left and the brick is just lime washed.

The soil has been removed from all except one side from what I can gather, this will help matters.

If you want this to be dry it needs to be redone in either lime render or board it all out. I would use gypframe if I was to board, adding vents to allow the wall to breath. I suspect the outside walls have been pointed with sand and cement, this should be ground out and repointed in lime.

If you seal the walls like what has been done, you will get problems down the line like what has happened. The walls have been sealed and because the water can't evaporate it's soaked up the wall and since the bottom half is water proof it's broken through further up. It will also be causing the brick to degrade....

Like John said, you need plenty of ventilation.

 

[joe-90]

It was originally lime - and damp. Peaps is an alternative plasterer playing at the good life.

 

[peaps2]

It was originally lime and damp because it was designed to be since it was a basement.

Dig out the sides, sand and cement pointing, internal work with waterproof etc Seals the walls and damp in

The brick under will be suffering and if you listen to people like joe you won't have much of a house left, before long.

You have already had modern methods applied and you can see where you are now....