waterproofing in a food growing area

MJ starts with ...
Hi everyone

I am at a loss to find out about the safest way to waterproof a limestone wall, which will be a food-growing area (fruit and veg all together).

I have been quoted for "bitumizing" the inside of all of the walls. Does anyone know if this is safe for edibles, or what alternatives exist? I have googled, but just come up with commercial products which look like a bitumen product, or a concrete-like product. The company say they are safe, but I don't know anything about it.

Any ideas? There is such a lot of great knowledge on this forum, I thought I'd try here.

Thanks
MJ

Julie says...
Don't know about the inside MJ, but years ago I waterproofed the outside of a brick wall with Bondcrete - probably diluted, but too long ago to remember.

I have also used it (1:4 Bondcrete to water) to seal a strawberry pot. It is very useful stuff.

MJ says...
Peter, the quote was just part of the overall quote for building the walls and paving, so hard to tell. It looks like a reasonable quote though, we think we'll go with this guy.

Julie, is Bondcrete the stuff you use on concrete floors (like garage floors)? I seem to remember that.

Jim, black plastic might be the go. Or, I could even use it next to the bitumen...

Will keep pondering

Julie says...
Mj, I think it is a PVA water-based glue. Don't know about the concrete floors though.

I made cheap signs for a garden by enlarging typed text on photocopier, gluing to board and coating with diluted Bondcrete. They lasted for years.

MJ says...
Amanda, yes, that is my primary worry. I might be better off just using a concrete "render" on the inside and leaving it at that. Limestone will go grey in time, anyway.

Jim says...
Hi Miranda you might want to seal the outside of the limestone also as this will help it keep its colour. I assume you have already bought it but if not than there are some reasonably good looking reconstituted limestones that wouldn't have these issues.

Jim says...
I have had reconstituted in for about 3 years and it hasn't changed colour at all. I did put some plastic on the back to be sure but even then I was advised that it wasn't necessary. Obviously it will depend on the type, but one of the main selling points of reconstituted is that it will keep its colour, so I wouldn't be too concerned.

MJ says...
I will ask my mum, but I thought she said she had recon... Hmmm.

Amanda, I have a bore, but it is unusual in that there is no staining from it. The next street, where I'm currently renting, does have the rust stains. Ours must be at a different depth.