A brick garage was built on the side of our house about 22 years ago, a few years before we moved in. Its 4.5 inch external wall is nearly on the boundary very close to a wooden fence, and sits on the base slab of the garage.
Our neighbour must have raised his rear access footpath app 3 inches above the common level of our two houses before the garage was built, so his footpath is app 12 inches above the top of the base slab of the garage.
I haven't yet removed the fence but it looks as though 'debris' has accumulated between the footpath/fence and the bottom of the garage wall. So, I imagine that when it rains very heavily (such as on last weekend) the rain ponds against the joint between the brickwork and the base slab and finds its way inside the garage. (normal rain isn't a problem)
I plan to remove the fence and to take out any debris by the garage which should cure the problem, as the rain should then flow away down the line of the fence.
But to make sure it lasts I was thinking of waterproofing the outside of the brickwork, particularly at the joint with the slab and about 12 inches above it. I would appreciate any advice as to the best way to achieve the waterproofing, as I have noticed a lot of different products from special mortars to brush-on bituminous/polymer liquids, and its hard to know which to use.
Many thanks for taking the time to read this and apologies for its length.