# Forum Home Renovation Retaining Walls  Waterproofing behind retaining walls

## barney118

What products are available to waterproof behind a block retaining wall? I take it a paint on option is the best. I take it a layer of plastic is not going to cut it? I plan on getting a waterproof additive in the concrete. Infill. How far do you go?  
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## barney118

I found an old thread suggesting grip set 51 is this still current  
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## phild01

2um plastic would be fine provided it never sees any daylight, in conjunction with geo fabric and a drainage blanket (comes in a roll).

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## paddyjoy

With the paint on bitumen stuff make sure it's fully dry before you back fill. I made the mistake of putting plastic against the bitumen and backfilling before it fully dried, checked it a couple of weeks later and it was still wet. I imagine it will never dry down there and will eventually wash away.

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## intertd6

> What products are available to waterproof behind a block retaining wall? I take it a paint on option is the best. I take it a layer of plastic is not going to cut it? I plan on getting a waterproof additive in the concrete. Infill. How far do you go?  
> Sent from my iPhone using Tapatalk

  Any suitable for the purpose paint on product will do the job, just plastic vapour barrier, no! It's a waste of time & money putting a waterproof additive in the mix as the block won't have it & still be porous, you will need to have some sort of protection for the WP like coreflute when backfilling behind the wall to stop rocks or debris puncturing the WP layer & rendering it defective.
regards inter

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## Oldsaltoz

> What products are available to waterproof behind a block retaining wall? I take it a paint on option is the best. I take it a layer of plastic is not going to cut it? I plan on getting a waterproof additive in the concrete. Infill. How far do you go?
> Sent from my iPhone using Tapatalk

  . 
Hi Barney,
I am a waterproofer and can tell you you should be looking for a product that comes with a proper membrane, this will help control the thickness of the product at least. I will also need to be protected when backfilled, and a proper drainage system installed just below the wall footings.
The seal should cover the wet side of the wall right down, over and past the footings step by at least 100mm. 
Anything less than the above is a comlete waste of of your time and money. this is the minimum standard. 
Good luck.
Sent from mi crappy computer using two fingers.. :Smilie:

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## phild01

> Any suitable for the purpose paint on product will do the job, just plastic vapour barrier, no! It's a waste of time & money putting a waterproof additive in the mix as the block won't have it & still be porous, you will need to have some sort of protection for the WP like coreflute when backfilling behind the wall to stop rocks or debris puncturing the WP layer & rendering it defective.
> regards inter

  Yeah, my slip-up thinking about another thing and not considering seepage.
But corflute is not really a suitable  drainage material and only offers buffering from the aggregate.  Use something like this instead: http://www.elmich.com.au/newsletters...inage_0505.pdf

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## intertd6

> Yeah, my slip-up thinking about another thing and not considering seepage.
> But corflute is not really a suitable  drainage material and only offers buffering from the aggregate.  Use something like this instead: http://www.elmich.com.au/newsletters...inage_0505.pdf

  the coreflute is not for drainage, only for the very economical protection for the WP membrane, drainage material is a separate layer when using this system.
regards inter

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## barney118

> . 
> Hi Barney,
> I am a waterproofer and can tell you you should be looking for a product that comes with a proper membrane, this will help control the thickness of the product at least. I will also need to be protected when backfilled, and a proper drainage system installed just below the wall footings.
> The seal should cover the wet side of the wall right down, over and past the footings step by at least 100mm. 
> Anything less than the above is a comlete waste of of your time and money. this is the minimum standard. 
> Good luck.
> Sent from mi crappy computer using two fingers..

  do you have product recomendations oldsaltz?

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## barney118

> Any suitable for the purpose paint on product will do the job, just plastic vapour barrier, no! It's a waste of time & money putting a waterproof additive in the mix as the block won't have it & still be porous, you will need to have some sort of protection for the WP like coreflute when backfilling behind the wall to stop rocks or debris puncturing the WP layer & rendering it defective.
> regards inter

  interd6 product from green shed? as mentioned earlier is gripset51 still the norm?

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## Oldsaltoz

I only use products that include a primer, a membrane and a thickish roll or paint on sealing material. 
Prime the blocks and the the footing the blocks sit on and let it fully cure. Then precut the membrain and roll it up, apply the first coat over about a metre of the wall, covering all the primed areas, lay the fabric on the nw wet product and add more o flood the membrane with a roller, then smooth out with a wide brush looking for any tiny pin holes as you go. 
Pull about 100 mm back off the wall and do the next meter as above till finished. 
Do a final check before the product fully dries and cover any pin holes or thin sections with a wide brush. 
Don't forget to remove the drainage pipe befor yo start or will get partly sealed. 
Good luck and fair winds.   :Smilie:

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## barney118

> I only use products that include a primer, a membrane and a thickish roll or paint on sealing material. 
> Prime the blocks and the the footing the blocks sit on and let it fully cure. Then precut the membrain and roll it up, apply the first coat over about a metre of the wall, covering all the primed areas, lay the fabric on the nw wet product and add more o flood the membrane with a roller, then smooth out with a wide brush looking for any tiny pin holes as you go. 
> Pull about 100 mm back off the wall and do the next meter as above till finished. 
> Do a final check before the product fully dries and cover any pin holes or thin sections with a wide brush. 
> Don't forget to remove the drainage pipe befor yo start or will get partly sealed. 
> Good luck and fair winds.

  Thanks, I'm going to be a bit restricted in getting in so I will be building the wall and waterproof at sumiliar times otherwise I won't reach in.  
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## DEMAK Timber

> I found an old thread suggesting grip set 51 is this still current  
> Sent from my iPhone using Tapatalk

  These days it's called "Gripset Betta"...

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## barney118

> These days it's called "Gripset Betta"...

  cheers, first slab/footing this weekend then build the walls.

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