# Forum Home Renovation Waterproofing  How the waterproof the edge where the wall meets the concrete driveway

## justonething

In this thread http://www.renovateforum.com/f198/wh...earers-113366/, I mentioned one of my problems. The investigation of either borer/ants is still ongoing, waiting for me to crawl under the house once again. In the meantime, I have also mentioned that the moisture contents of the joist and bearers adjacent to the external brick wall is about 15 - 16%. This might not seem much, but considering the rest of the house, including the garage is around 11 - 12% and the wall feels slight damp. I think the dampness might have contributed to my problem of borer/ants/termites/rot. 
I think I have discovered what caused the wall to be damp, while the soil under the house is bone dry. We have a small front porch with a flat roof (see photo). Water from the spouting is discharged directly onto the concrete driveway. The way our land laid makes sure that water will always runs to the house, and then along the external brick wall as flows down the gently sloping concrete driveway. I think much of the water is trapped at the corner/intersection where the wall meets the driveway and leaks into the subfloor.  
Twenty years ago, I caulked this corner with some sealant ( I don't remember what it was exactly but it could be a grey silicone). Obviously some of the caulking has come off the surface, and weeds have set roots in it. I measured the moisture content behind the caulking today, it was 25%. I think the problem with the caulking was that there were always soil and dust trapped at the corner no matter how clean I tried to get and it is always damp and hence the sealant adhesion wasn't perfect. Eventually it came off sometime during the last twenty years.  
I intend to get the grinder out and cut a 5 to 10 mm grove along the corner and wipe clean with methyl spirit. I want then to first seal it with some kind of sealant, and then secondly raise the corner to a bead of say 20 - 25 mm radius to divert water away from the corner as it runs down the slop. But I'm not sure what is the best sealant to use in the 1st or the 2nd step. 
The first step I am thinking about using a epoxy resin that tolerates a bit of dampness. The 2nd steps I'm thinking about using flexible water based pointing compound like flexipoint. 
I would like people's opinions on this? Should I just use polyurethane sealant for both steps? If I did, would it last? I wouldn't want to do it again in 10 to 20 years.

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## Oldsaltoz

I have been epoxy resins for many years and can assure you, any sign of moisture will result in a failure. 
However, there are now epoxy based resins available in the form of two sticks that can be needed together and will stick onto a wet surface. Not cheap though. 
UV can also effect many of the sealants available and it's worth checking before you purchase any. 
In this situation I use a product called C-1, it looks like pure cement and when mixed with a little water starts warming up, it actually forms crystals in the joint and seeks out moisture, filling and gaps. 
Problem for the non tradie  is that it comes in a 12 kg drum for a bit under $400.00 so economical unless you have huge area. 
I have been using it to patch up leaks in an underground car park, not accessible from above ground, covered in lawns and palm trees. Originally used to stop a large dam leaking on the dry side of the wall. 
Good luck and fair winds.   :Smilie:

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## justonething

Oldsaltoz, what about using sikaflex pro? Would they last?

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## Oldsaltoz

> Oldsaltoz, what about using sikaflex pro? Would they last?

  
According to site information.
Quote- Sikaflex-PRO is a one component, thixotropic, polyurethane based joint  sealant.  It cures under the influence of atmospheric moisture to form  an elastomeric material with adhesive properties, in some cases without  the need for priming of the substrate.End Quote. 
Based on the above I would say go for it. I have used this for construction joints in brick walls in the past. 
Good luck and fair winds.   :Smilie:

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## justonething

The data sheet says sikaflex-pro has excellent adhesion to bricks and cement. Just have to make sure the area is mechanically clean of mould, soil and dust.

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