In relation to my workshop build, on the back wall - there is a gap of 2"-3" between the wall and the drystone wall. Now I don't really expect any issues, but would like to coat the outer face of the blockwork with something - to reduce the possibility of any moisture making it thru. Now there will be a vapour barrier on the inside, but part of me would rather deal with it on the outside - the old prevention is better than cure.

I'm thinking that bitumen based membranes\protection boards might be bit of an overkill.

Any recommendations on what to use and is it readily available?

A couple of coats of "Synthaproof" which is like a bitumen emulsion should do the trick. You should be able to get it or an equivalent such as RIW from a good builders merchant.

Jason

_________________
Don't waste wood, it doesn't grow on trees you know!

Fantastic - will ring the usual lot tomorrow and check availability\prices. Thing is the gap is relatively narrow - I thought it best to apply the stuff to each course (after it's set) - almost to the top before the next one goes on with something like a long handled radiator roller.

Otherwise it'll be a pig afterwards.

I used Synthaprufe to tank the inside of my workshop. It's lovely stuff, goes on like thin paint but dries like rubber. It recommends 2-3 coats but I went for 5 as a 5ltr tin goes a long way. It's not cheap tho, £50 IIRC

Cheers - just looked in my Selco price guide, £21 +vat for 5 Litres. Or £29+ vat for the LAC version (Lord knows what that is).

I must have got the £29+vat one. Can't remember what the difference is.

Dibs

Aquaprufe £31.40 + vat / 25litres from a builders merchant.

I just finished some tanking on the back of my house, which I covered in the following blog post;

http://thingswemake.wordpress.com/2009/ ... -in-again/

If you don't have direct ground contact then something less dramatic would probably do the job

Cheers, Ed

Cheers Ed - thankfully on the workshop no direct contact for the most of it. The poured return is around 12" off the slab - So I don't think moisture is going to be an issue there, where it is on average 8" thick. The wall that is built on top of that - there is a gap of around 2" between that and the drystone wall. So with a coat or two of either Synthaprufe or bitumen paint - should be ok.

Although the basement under the garage next to the workshop (next stage of the build) will make your headache look tame. At least the bottom metre of the basement walls will be below ground level so - membranes and waterproof concrete springs to mind.

Dibs

Had a damp water penetration problem

Solved it using Soverign Chemicals Hey'di K11

It's a micro powder wen mixed with SBR ( Like a high strenth PVA ) makes a slurry which you paint direct to the wall

They use it for sub ground and basements etc
Heres a link to a pdf of the product on the company's website

http://www.sovereignchemicals.co.uk/Cor ... usage..pdf