Need Advice For How To Make My Garage Damp proof.

Davesnave

hk213 said:

One of the most cost effective methods for waterproofing garage walls is by using tanking slurry to prevent dampness. Tanking is commonly used in cellars and basements to prevent groundwater entering, however, tanking slurry is also highly effective at preventing damp walls in a garage. It is the cheapest and most effective method of garage waterproofing.

Copied and pasted from here:

https://www.permagard.co.uk/advice/waterproofing-a-garage

Not exactly an unbiased source, but they should at least be credited with it!

FreeBear

Davesnave said: Not exactly an unbiased source, but they should at least be credited with it!

Thought it had the smell of snake oil from a damp proofing outfit... From their "How To" -

Tanking slurry requires at least two coats. The first coat should be applied directly to the brick or blockwork by brush in a horizontal direction. Normally we recommend applying the slurry up to one metre high as this will combat most rising damp scenarios.

This rather assumes the damp is purely due to rising damp.... No mention of cold damp air from outside or moisture coming up through the slab.

daivid

I've stored clothes in an unheated, connected garage (in plastic boxes) for 3 years and no sign of mould so far. Mice have chewed a book or two though. I think the suggestion of vacume bags is better still for mould prevention. Though mice could/would chew straight through.

strawberries1

So we got the roof cleaned, replaced flashing, repointed bricks and painted external wall with masonry paint.
We notice damp water mark where the external side wall meets the floor. On the outside is slabs making a pavement btw the garden and the garage. 
What shall we use to stop this damp? Something that looks like flashing (damp course maybe?) seems a little visible from 2 bricks above ground.
The damp on the all was from damaged brick which has now been replaced. 

FreeBear

Cut the slabs so that there is a 200-300mm gap to the wall. Dig a shallow trench in this gap and back fill with gravel. This is called a French Drain and is often a good idea around a lot of buildings.

strawberries1

FreeBear said:

Cut the slabs so that there is a 200-300mm gap to the wall. Dig a shallow trench in this gap and back fill with gravel. This is called a French Drain and is often a good idea around a lot of buildings.

Looks like it will have to be tanking it. There's nowhere for the water to go if we dig a trench outside and will be a much bigger job to cut or move the slabs.