# Forum Home Renovation Waterproofing  Waterproofing a brick wall - One side has irrigated garden bed and soil up it

## DaleBlack

Hi I have a brick garage with a storage area partly newly built, at both ends there is an existing single leaf brick wall that has garden beds with drip irrigation and soil up approx 600mm and maybe 1m of soil up the wall in the other garden bed. This area may even become a habitable room one day so we do not want moisture creating mould, smells etc 
Below is my attempt at waterproofing 
(note both images were taken during the exercise so already show black bitumen coating)   
2nd wall    
I have relocated the nearest drips to about 500mm from the wall. 
the 2nd wall in particularly had moisture seeping through, that was mainly due to the hole drilled by a sparky to push through some 12v garden wire. He just drilled the hole instead of inserting a conduit tightly see below   
Wall 1 
I initially steel brushed and high pressure hosed off these walls to remove ingrained soil and roots that were all in the mortar joints. 
I then troweled on some mortar to cover the worst gaps or holes, though the whole surface is still very bumpy. I am sure a professional would have had the whole area one smooth surface. 
I was initially only going to apply Crommelins water based bitumen single pack, which requires a completely dry substrate. 
I have a moisture meter and the troweled on mortar kept reading 15% plus, sometimes 25% even 6 weeks later. 
Not wanting to wait further I purchased the Crommelins Damp Stop which can handle these moisture levels.  Dampstop: Sealers: Crommelin 
Its a two pack expoxy coat and their tech line said it can then be a primer for the water based bitumen product. 
I applied two coats of the Dampstop and then tech support said i had to get the first top coat of the waterbased bitumen coat on within 8-12hours after the final 2nd coat of the expoxy.
Something about it otherwise hardens beyond the ability of the water based coat to adhere. 
Wall 1 Expoxy coat in grey       
Side Note the ledge at the bottom in the below image, which was a result of my poor formwork which created that as I attempted to motar up the brickwork/mortar joints and other sections with the odd partly missing brick - the sheer drop should have been one flat surface from top to bottom, i assume horizontal surfaces area a weak point if moisture can just sit there.   
Still it dried like a coating of plastic. Two coats. 
Bitumen one pack water based coat below - 3 coats, brushing different directions each time.    
Wall 2   
Note that downpipe you see below , ended up being pipe away to a soakwell so shouldnt be introducing moisture.  
The below exposed bricks is what it also looked like for Wall 1 above, prior to my smearing a mortar coat over it all.   
Note the area at the Wall to Footing junction   
I decided to add a small mortar cove over the wall to footing junction 
tbc in next post

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## DaleBlack

Mortar cover over Wall to footing junction below   
below is the expoxy coat, you will note other then the cove above, i left the bricks exposed. I probably should have had the guy who did the render , render all the way down to the footing, however it was not dug out like this that far down on the day. 
I had to constantly jam the brush into the mortar joints and into the chased copper pipe you see which no doubt leaves a higher chance for small gaps in the waterproofing coat compared to if it has been cement rendered, on such a smooth surface i could almost have just rolled these coatings on. 
Below is the bitumen coat over the expoxy and over the cove i made   
More generic shot   
Finally on both walls, partly to protect the coatings from anything sharp in the soil like small rocks i put a 200micron plastic sheet down, covering the footing and up the wall higher then where the soil will end. 
The white stuff is FMG Homeguard, used as a damp proof and termite barrier that i had leftover however I normally use 200micron black builders plastic. 
The really thick black stuff is some left over expensive Root Barrier product that i shoved in like using the cheap corflute to protect the plastic from rocks.

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## joynz

Couldn’t you just separate the end of the garden bed from the garage?

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## Oldsaltoz

Looks like you have managed to complete the task to a reasonable standard, love the coving on the wall to footings joint, though I would have mixed some sand with the bitumen and used a tennis ball to smooth it out and left it to cure before overcoating it. Filling in the gaps with a mortar mix is best done by first adding one of the many additives available that add fibres to the mix makes it stronger, and less likely to crack. It also makes the coating application easier and faster and improves stabilisation.

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## DaleBlack

Hi Oldsaltoz, 
 do you think the epoxy step was worth it though? or because of the dampness issue I had no choice but to go first with the epoxy to then allow the water based bitumen coat to go on.   

> "though I would have mixed some sand with the bitumen and used a tennis ball"

  ok, i simply brushed the black bitumen on with a brush (this after brushing on the two part epoxy x 2 coats) - 
Does the sand add to its strength ?  
given part of the wall i left with open mortar joints, how would the tennis ball have gotten into those gaps? or the brush is fine for those and then roll the ball around after 
"left it to cure before overcoating it" 
The cure times for epoxy were first coat - 4 hours I think then 2nd coat - then on the tech lines advice topcoat of black bitumen within 8-24 hours. the 2nd and 3rd black bitumen top coats were about a day apart, such that there was zero stickiness when i touched it. 
Is the below what you mean re fibres? i see they also substitute SBR for water        

> joynz    			 			Couldnt you just separate the end of the garden bed from the garage?

  unfortunately the neighboring house is higher, there is limestone blocks and a wall along the border, but they do not go deep enough to the bottom of my retaining wall, so if i did end the garden bed section earlier, about 300mm of sand under the limestone blocks would be unsupported. So i could have done it but would need to have addressed that issue. You can sort of see what I mean in the first few images in my op.

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## Oldsaltoz

Question: Do you think the epoxy step was worth it though? or because of the dampness issue I had no choice but to go first with the epoxy to then allow the water-based bitumen coat to go on. 
As a person who has done a lot of fibreglassing, I know that NOTHING will stick to and epoxy other than a lot of proper preparation and more epoxy. there are inter-coats available but none that work 100% in my experience. However in your case, the coats will be under 'some' pressure by backfilling, so provided there is little to no movement you should be OK. Fingers crossed. 
I am not sure what product you were using. I like the 3 coat bitumen based system, starting with a wire brush to remove any loose material. Then fill any cavities with a coarse sand mixed with the product. Then a watered down primer coat. This dries quite quickly as things like blocks tend to suck in any moisture. Next is the first coat, always working from the bottom up using a roller rather than a brush for better distribution and speed. working from the bottom up means any excess material collects on the top of the roller so also efficient. The time between coats is dependant on the size of the area, for instance, a typical flat block wall, say 15m by 12m would take about an hour per coat. curved areas like your job take just about the same time making sure all areas and crevices are properly coated.  
The use of the tennis ball I referenced was only ever used on right angle corners to provide a smooth transition at the same level making it easy to coat with a wide roller.  
I hope this covers your questions.  :Smilie:  
Good luck and fair winds.

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