# Forum Home Renovation Retaining Walls  Besser block retaining wall - render or cladding?

## dansa

Hi, 
I am doing some renovations at my place as owner builder. 
A tradie built this Besser (concrete) block retaining wall for me. It is 1400mm high, steel reinforced and filled with concrete sitting on a solid footing. It is rock solid.
I have laid a 100mm socked AGI pipe behind and covered with blue metal but only about 800-1000mm and then covered with dirt to the top.
I havent done much homework about how to proper waterproof it on the wet side. Now, when it rains the water seeps through the retaining wall and the dry side gets wet. My plan is to render it but with the moisture that goes through the blocks every time it rains, I am concerned the render will get stained and at some stage it might fall as well.
I am after some suggestions if it is worth trying to waterproof it on the dry side and then render on top (expensive) or should I batten up the wall with some composite battens to resist the moisture on the dry side and top and cover with fibre cement and then paint with a texture paint.
I can do the cladding so it will be cheaper than hiring a renderer and then pray the render will not fall at the next heavy rain. 
Any pros and cons for cladding? 
Thanks.

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## Tools

You need to dig it out and tank the wall before back filling. 
Tools

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## pharmaboy2

Cladding isn't the answer, dig it back out, water proof, refill, render   :Wink:

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## dansa

> Cladding isn't the answer, dig it back out, water proof, refill, render

  I would dig if I could but is all rock behind the wall and there are sections where there is only 200-300mm gap between the rock and the wall. Its impossible to dig such a narrow trench to 1.4m in depth. Also the retaining wall is 15m long. Its a lot to dig.
Why is the cladding not an option?

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## havabeer

Put a trench or gutter I front of the wall to direct the water somewhere else 
basically you needed to water proof the wet side when you had the chance, otherwise your just forcing your brickwork to stay wet

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## dansa

> basically you needed to water proof the wet side when you had the chance, otherwise your just forcing your brickwork to stay wet

  I know that but is a bit too late and I am looking for an alternative solution.  :Rolleyes:

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## Bigboboz

So what you're thinking is a cladding that isn't completely touching the wall and keep a gap for moisture? Even ventilation between the wall and cladding?

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## dansa

> So what you're thinking is a cladding that isn't completely touching the wall and keep a gap for moisture? Even ventilation between the wall and cladding?

  Exactly! The cladding is not touching the wall. I can prime it and seal it on the inside before I put it on. The cladding will stay dry and I can use a texture paint to paint it on the outside.  I guess the bluebird will be the best option.
I can also make some weep holes at the bottom in case the water needs to run out or I can even leave a small gap, let’s say 5mm at the bottom.
What do you think?

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## pharmaboy2

Before you do it, at least remove as much of the soil, then the blue metal that you can, paint the wall with a crystalline type waterproof treatment for concrete as far down as you can, then you can probably do the same on the front of the wall.  When you replace the fill, make Sure it is well covered by geotechnical fabric, and don't put soil right up to the edge of the wall. 
see how it goes and if you get salt/calcium coming through over winter, if not, render it, but the render will need an additive. 
cladding will look terrible unless it's an architectural type finish, which will require expensive installation .  Blue board or such will just look like blueboard over the top of a wall - it will not look like a rendered wall 
a matrix type revealed joint cladding would look ok, but it needs to be installed correctly, but after you have at least made an attempt to waterproof the wall - mould and moisture will still come through. 
id still just dig/jackhammer the back wide enough to take it right down to the bottom of the wall. 
btw, murobond type paints breath if you can get it nearly waterproof

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## Marc

I had a similar problem with a core-filled block wall. Brickie build it against dirt without any drain at all. Had to go next door with an excavator and dig a trench right next to the wall all the way down to the footings. Not easy and needs a zero turn excavator to go safely next to the wall. 
Once open, need to let it dry, water proof, lay plastic against the wall and the bottom of the trench. Geotex inside the trench both sides and enough to cover the top. Ag pipe all the way down hill, fill with blue metal, gravel or recycled concrete 20mm, cover the top with the geotex and have some extra gravel on top.  
I am afraid there are no alternatives, short of buying a 44 gallon drum of silicone sealer and pouring it against the wall, and even that may not go where you want it to go.

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## toooldforthis

That ABC Dream Gardens had that problem in one episode.
They got some dudes in to treat the wall, it was effervescencing, very expensive. Then sealed it. 
I doubt it solved the problem more than til the end of the photo shoot. But you could look it up. It was an early episode where there was a huge block wall built in the back yard, had a pool, and terrace at the top of the block from memory.

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## Tools

You can buy negative pressure waterproofing that can be put in the outside of the wall. ABT make one, as do others. 
Tools

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## dansa

Thank you!
It looks like cladding is not very popular, is it? Is it because it looks "cheap" or because is not a long term solution?
Can I render the retaining wall after I do the negative waterproofing?

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