Waterproofing blockwork

[macadonald]

Hello,

I have just built some raised bedding out of blockwork about 3-4 foot high. I will be filling these with soil and rendering the outside. I had planned to use a plastic lining on the inside to stop water/damp within the soil from seeping into the blocks and ruining the outside render. It's just crossed my mind that a painted on sealer might just do the job.

Can anyone advise please. Also what the best stuff to use would be.

Many thanks

 

[Blagard]

I have always used RIW sealant. It is like a bitumenous paint.

Whilst a proper job would be to use one of their systems, I have found that for the odd bit needed in a garden situation a couple of coats has always worked for me. http://www.riw.co.uk/lac.htm

Some builders merchants will stock it or get it for you.

Main site is:
http://www.riw.co.uk/

Edit - a quote from the retaining wall part of their site
"RIW LAC is most often used to protect landscape walls, and is applied to the soil face of the wall with appropriate drainage or protection boards "

 

[macadonald]

Thanks Blagard,

Looks like good stuff, just need to find somewhere that stocks it now. Any idea if you can plaster over these products?

I suppose the upside of using this over plastic, is that it's slightly flexible and less likely to tear over time.

If anyone knows of more readily available equivalents, then please let me know.

Thanks

 

[maltaron]

This one from Wickes is worth a look.

http://www.wickes.co.uk/Liquid-Damp-Proof-Membrane/invt/241217

 

[noseall]

Polythene, so long as it is not exposed to the elements, will last a long time.

Both painted and mechanical damp proof products have their merits so it is up to you to choose.

I have to say though the builders' choice is polythene sheet.

 

[r896neo]

you can render over synthapruf