damp proofing with DRYZONE

Ken,
I discovered that I had rising damp in my kitchen walls about 2 years ago.The damp proofing company that I got to do the job used Dryzone.I had to strip all plaster and render up to a height of 1 metre.They then bored holes about 150mm from outside ground height and then they injected the outside walls.they then bored holes in the inner wall and again injected the Dryzone.I had too leave inner walls for about 6 months to dry out before renovating plaster could be applied.Everything is ok so far.Company also guaranteed job for 20 years.
Hope this helps.

 

I think the official BRE advice is to leave it for 6 months as this gives the wall the best opportunity to dry out. However in reality most walls are rendered the same day. Because the sand-cement renders used over damp-proofed walls are vapour-permeable the wall will dry out eventually - it will just take longer.

The Dryzone website - http://www.dryzone.eu - doesn't say much about replastering, but I think it is covered in the rising damp guide that can be downloaded from the site

I recall that rising damp treatment was covered in one of the BRE's "Good Repair Guides" which you can buy from the BRE websitre for about £10 each - http://www.bre.co.uk/

 

next time someone asked you to hack off for damp proofing take 1.20 and not a metre , I've seen lots of damp proofs with damp above the 1 metre mark ...

 

I think you're supposed to replaster up to 30cm above the highest signs of damp. To be honest, it's often less hassle to just replaster floor to ceiling - it doesn't cost that much more and you don't have to risk doing the job again if the damp rises above the new plaster (rising damp can actually rise more than 2m in some situations!).

 

Ken,
The reason that I removed 1 metre of render is because thats what the damp proofing company wanted.I dare say if the dampness had risen higher up than that they would have wanted me to remove more.

 

Just remembered.Damp proofing company also said that for 1 inch thickness of walls that I had to leave the plastering for 1 month,hence the time of 6 months before replastering.

 

Have a look here
http://www.constructionsupermarket.com/index.php?act=viewProd&productId=309
I have done my own DP using these products. Follow the general guidelines freely available on the net:- hack off plaster to 1200mm or 300mm above highest sign of damp, drill into mortar course 100mm above floor at 100mm spacing 12mm dia and 75% depth of total thickness of wall. After injecting DP cream paint surface of wall with 50/50 diluted SBR bonding agent and plaster with renovating plaster before SBR dries (dries smooth as glass) Finish with normal finishing plaster and then emulsion paint.

 

Forgot to add, use stainless steel screws when refitting skirtings etc

 

The trouble is with that cheap Remmers cream that you get from construction supermarket is that it has a very low amount of active ingredient (silicone). When it first came on the UK market about three years ago their salesman tried to sell it to me and gave me a German datasheet saying you had to drill 20mm holes and fill them three times! To try and compete with Dryzone they then modified their datasheet to match the specification for Dryzone - even though the Remmers product contains about a quarter of the active ingredient!

Damp-proofing is a messy and disruptive business so I always suggest that people try and get it right first time - i.e. use decent products and don't cut corners with replastering.

 

Hi Ken. I was just wondering if the damp came back or if the DPC actually worked. I've not had much success on my own place. Keeps failing and it is very disruptive.
I would like to know how many have failed and had to be redone.