Question about tanking....?

[troubleinstore]

Yesterday, I had the building control officer come to see me about some damp which is affecting the inside of the outside wall at the back of the house. He told me that the reason for the damp was when the previous occupier of the house had had flagstones laid in the back yard he had bridged the damp course. This part of the puzzle is easily remedied. What I am concerned about is that he told me I would have to have all the back wall tanked. Damp is about one foot up the wall. So could someone advise please. What is tanking. Do I have to rip up the concrete floor (yuk), can I plaster over it on the walls.... etc etc etc. He did say that the problem was not considered urgent. Your help would be most appreciated.

-- troubleinstore

[BigWallop]

Tanking is just putting a waterproof layer on the inside of the walls and making sure that water runs between the inside of the existing wall and the outside of the new tank type structure. It's best for you to dig out the flag stones and make good the problem that's causing the damp, then you won't need to do any tanking on the inside because the damp won't occur again.

Bridging the damp proof course of walls is a common problem that cowboy builders cause and is the easiest to remedy by undoing what they've done. It might take a couple of summers or a dehumidifier to remove the damp marks, but this is better than spending thousands on something you don't really need done.

[troubleinstore]

Many thanks for the above reply. What worried me was the fact that upon removing the flagstones, there would be 2 foot gap from the others that are there to the house wall, but I have decided to cut about 6 inch off the flags and and then put a border stone what you have in gardens so that it makes a trough:-

house x x x - edging stone x xxxxxxxxxxx - flagstones xxxxx ! trough

the reason for the trough is that water can run straight into the the drain.

As I will be replastering the inside walls anyway, would it not be prudent to put some tanking on the inside walls and if so, could you reccommend a suitable waterproofer to do the job...?

-- troubleinstore

[BigWallop]

The wall really needs specialist treatment because it needs to be injected and then fully tanked with the proper materials to make it sound and to stop the further growth of fungal spores and things. So try your home buildings insurance people for some more advice on this as it will alter your policy if you don't tell them about a possible structural fault and then make any claim against the policy.

My advice is, you get more advice from a specialist, reputable, company on this problem and not to try and tackle it yourself, because you can cause more problems if this type of job is done wrong.

[Christian McArdle]

You can sometimes get away with filling the trough with gravel if the drainage is good. Although it sort of bridges the DPC, the water wants to go down into the well drained trough and might not reach the house wall to cause problems.

Christian.

[troubleinstore]

I should have, but failed to mention that the flagstones are laid upon the original concrete yard. I do not know how deep the concrete is so I will have to get the drill out and do a few pilot holes

-- troubleinstore

[BigWallop]

If the concrete is the original top surface, then how have the flag stones been laid on top of it ? If they've been built up on top of the old surface, then you should only have to remove the new stuff back to the old surface of the concrete. That's taking that the old concrete surface didn't produce the same problems of bridging the existing damp proof course and was well drained originally.

[Jerry Built]

What! You can get a bloody pen-pusher to come out and look at your property just like that?

Often happens, rendering over damp is popular too.

Once you've removed the cause of the damp, you may not need to do anything. I wonder whether he means tank in or out side. Tanking is just making a waterproof barrier in or around your building. Inside, you could hack off existing damaged plaster, make good (flat!) the surface, use bitumen emulsion in 3 coats applied ar right angles, the last one being "blinded" with sand, and re-plaster. Look at the instructions on the tin before you buy (visit Jewson's or somewhere).

J.B.

[troubleinstore]

Yep, I raang him up and he was here within a couple of days.

Is this something strange....?

I have always had good relations with my local council. If I need help, they are very approachable and fall overthemslves to try and help, it's just that he didn't fully explain what tanking was.

I can sort the outside problem out very easily. I can also put the earth rod in that has been sat in my shed and I have been meaning to do for the last 6 years.

Aye, he meant tank it on the inside.

-- troubleinstore

[Hugo Nebula]

On Thu, 13 May 2004 14:06:27 +0100, a particular chimpanzee named troubleinstore randomly hit the keyboard and produced:

Well, yes. Unless you've claimed that the building is dangerous (i.e., in imminent danger of collapse), a BCO wouldn't normally get involved in condition surveys. In some councils Building Control perform an additional role of Grants Inspector or COW.

[troubleinstore]

I only asked for advice. I suppose it's how you do that and the manner in which you do it.

-- troubleinstore