Chasing walls already treated for damp?

[hillbillie]

I'm possibly about to rewire a basement flat with a serious damp problem. Some of the walls will have the damp treatment done after I have finished (or after 1st fix, I'm not sure) but some have already had damp treatment. So, what do I need to do to maintain the integrity of the damp protection when I chase and cut out the brick for the back boxes? Is there some sort of sealant or special plaster I need to use around the boxes and in the chase? I have no idea what sort of damp course was done.

Any assistance would be very welcome.

 

[Deleted member 26818]

You really need to speak to the people who did the tanking.
There's a very good possibility that any chases will compromise the damp proofing, and whatever seallent used on the walls may also have to be used inside the chases before any cables are installed or any filling conducted.

 

[Des 56]

You really need to speak to the people who did the tanking.
There's a very good possibility that any chases will compromise the damp proofing, and whatever seallent used on the walls may also have to be used inside the chases before any cables are installed or any filling conducted.

Do not go making chases without first contacting the building inspector,any drilling or chases will compromise the tanking already carried out
Some building inspectors may permit you to drill and insert sealant before screwing etc,others will not permit any disturbance

 

[Engineer54]

Need much more information than that!! For a start, what sort of damp-proofing has been done?? Also was it internal or external. Reinstatement of damp proofing can be simple or neigh on impossible, all depends on what system used and how applied!!

 

[markc123]

You need to get in touch with the building inspector asap probably try contact whoever did the damp-proofing aswell. It may not even be possible now, you're client sure has ****ed things up here by the sounds of it.

By all means start on the untreated walls, but i wouldn't touch the rest of it with a barge pole if i were you at the moment - because you'll be the one that gets the blame.

 

[londonlec]

In addition to what the others have said, the firms who do the DPCs usually give a 25/30 year warranty on the works, but if you drill any holes in the surface the warranty will be void.

Usuallly they only go up a meter or so can you fit accessories above that height.

 

[Deleted member 26818]

I think it's a basement Londonlec, so no 1m height.

 

[MDJ]

You really need to speak to the people who did the tanking.
There's a very good possibility that any chases will compromise the damp proofing, and whatever seallent used on the walls may also have to be used inside the chases before any cables are installed or any filling conducted.

Totally agree here, don't do anything without talking to the original Plasterer who added the tanking, unless you have good insurers who won't mind shelling out a tidy sum in the future.

 

[Heisenberg]

If it been 'tanked' then you're going to have real problems :boat:

But how about convincing the customer that having bare galvanized trunking is the latest craze doing the rounds on Grand Designs, and that you'd be happy to install that :cool3:

 

[MDJ]

If they did ever install that they would have to pump silocone into the holes before they added the rawlplugs, but surface work is an option, I expect the original plasterer would say something similar.

 

[hillbillie]

Many thanks to all of you that posted above.

Basically then, I'll have to chat with the people doing the new damp course and hope they'll help me out (unfortunately the other spark going for the job works for them).

 

[daimack]

I chased out some walls last year that, unbeknown to me, had been damp proofed at some time in the past. It wasn't a pretty sight when the damp started finding its way back through my chases :sad: . Fortunately (or not depending upon how you look at it) it was a property I was renovating to let out myself and we had to have other walls re-damp proofed anyway, so it just meant a bit of extra grief rather than major problems, but I agree with others, chasing will probably compromise the damp proofing.

 

[Guest111]

I saw one done and the tanking was a polythene liner under the plaster,everything was done surface and bonded to the plaster with gripfill,it was explained to me as follows.Tanking is like a bucket,but instead of the water being in the bucket the water is outside and the room is in the bucket.We all know what happens when we get a hole in our bucket of water don't we lol.