# Forum Home Renovation Waterproofing  Waterproofing between concrete slab (roof) and brickwork

## hitch77

I have recently bought and moved into a house which has a deck/verahdah out the back. The floor of the deck is a concrete slab, which forms the roof of the shed underneath. Please see this other thread for some photos of the construction etc (and I'll add some close up photos of the problem I'm describing here if needed) :  http://www.renovateforum.com/f214/ne...uld-do-114477/ 
The way it currently is, when it rains a lot of water builds up on the verandah. There are small holes at the base between the joins of the breeze-blocks that currently form the fence around the deck. For most of these, the previous owners have put some copper pipe through the hole to run the water out and away from the slab. However one of these holes doesn't have pipe. Therefore the water oozes out of the hole, collects on the outside of the fence and runs down the side of the slab. It then either: runs between the slab and the brickwork, into the inside of the shed and runs down the wall, orruns down the outside of the brickwork, causing lichen and moss to grow, and I assume, move through the grout also affecting the inside of the shed.  
This then means that the shed is not watertight, and all of my tools, bikes etc. are then susceptible to rust and it is just generally unpleasant.  
I'm wondering what the best, most cost effective DIY method would be to seal this up. I've spoken with a few people who have talked about having the grouting redone, having Silex (?) applied over the outside to waterproof etc. however these options are expensive and not necessarily easy/DIY. Also, as noted in the other thread, we may be renovating the whole back of the house in 12 months or so, so don't want to invest too much in what may be a throw away solution. 
I was hoping when we next have a run of hot days and things can dry out a bit, to simply try putting a bit of silicon along the join to see if it would make a difference. Above the door (in the photos in the thread linked above), there is some kind of glue with a thin strip of flashing over the join, and it appears to keep all moisture out. 
I've heard though, that standard silicon won't bond too well to concrete/brick work?  
Anyone have any recommendations or suggestions? 
Before I spend a few thousand I'd like to try some other options.  
Obviously it would be good to fix the problem of the water pooling, which I'm also planning to try...

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## droog

I had a problem slightly different but maybe it could be adapted to suit.
We had a concrete suspended balcony and the water would run down the side and then run back under the balcony, I wanted the water to fall at the edge rather than running back underneath the slab. 
I attached an aluminium angle at the edge of the slab with mansonary anchors and sealed between it and the slab with sikaflex, then painted the whole edge of the slab and over the angle with Bondall Pondtite  Bondall - PondTite creating a drip rail.
The Pondtite was also able to fill the voids in the end of the concrete slab left from casting. 
We have since moved from that house but was sound and required no maintenance in the 8 years after I did it.

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## Oldsaltoz

Seems to me you have a few tasks to complete. 
The Copper pipe should never have been installed and should be removed and replaced with PVC. The problem being that Copper reacts with concrete and should be taped to seal and protect it. PVC on the other hand needs no treatment. 
Also that the the Copper or PVC drains or Spitters to the right name are not the best because the wind blows the airborne water back into the wall. 
It also seems that no matter what renovation you do short of removing said wall, it will continue to leak unless properly treated, so might like to sort that first. 
If you decide to keep the balcony, then look at installing a collection gutter under the spitters and direct the run off to down pipe, this means less water on the walls and stains from spitter spatter.
    Oh I like that line :Smilie:  
Last but least you need to improve the air flow under the structure or provide better protection against moisture entry. 
There are special angles designed for balcony edges that will not only prevent any water running of the edge but direct it to a proper drain. This type has a up-stand on the outer edge. The more common angle is a drip rail with a turned down edge, the common mistake made when installing these is not leaving enough gap between the downturn and the end of the structure, anything less than 20 mm just is not enough.  
Good luck and fair winds.

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## hitch77

Thanks for the great ideas droog. Was your angle 90? I naively expected to find angle that was > 90° at bunnings, but as the guy said, I'd struggle to think of a commercial reason why you'd need that. I didn't think 90° angle would be any good. I could mount some channel, to run it off, but would prefer the drip rail idea. Bunnings had crescent aluminium, but it didn't look like it would sit out far enough from the wall...

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## droog

Mine was 90 but it was installed under the edge of the slab, you will need to mount to the face, there is plasterer's angle at 135 degree,  Peer Industries 2.4m Gold P135 Internal Angle Plaster Trim I/N 0730147 | Bunnings Warehouse 
You would need to use a matting with the waterproofing as the angle is perforated Bondall - Polyweave 
This would get you a drip rail edge about 20-25mm out from the edge of the slab.

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## Oldsaltoz

90 degree angle is available in most aluminium distributors like Ullrich Aluminium, and cheaper than Bunnies.

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## phild01

> 90 degree angle is available in most aluminium distributors like Ullrich Aluminium, and cheaper than Bunnies.

   ..and the better suppliers have anodised and powder coated.

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## Oldsaltoz

Also now available is an anodised, polished angle, almost looks like Chrome.

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