Brick garage and damp

We've got a brick garage (single brick walls). There are two damp
1. Retaining wall for next door's garden. The close is built on a
hill and next door's garden is about 500mm higher than the floor of
the garage. When it rains very hard there's a gentle seep through the
wall that pools on the floor - maximum 50mm of water, so not a lot.
I really don't want to mess around waterproofing the outside wall as
it's not a big deal. Normally it wouldn't matter as we don't use the
garage for much. However I was hoping to fit our old kitchen units
into the garage today when I found out about this and there is enough
water to blow them.
The good news is that this is on the wall that is to form the side of
the run and is well below the height of the worktop, so it's only
going to affect that one side.
I'm currently thinking of a bodge using a piece of perspex to protect
the side of the unit, perhaps combined with some plastic sheeting
under it. Or could an internal sealer paint be expected to hold up to
this low-volume seeping? Even if it could, is it a good idea to
effectively seal that damp into the brick?
2. Driving rain seeps through wall. A bigger, but less urgent, issue
is that when it rains hard the prevailing wind drives it through the
other side wall. There are numerous seeps through, although this
tends to just lead to really wet walls rather than pudddles on the
What's best practice here? I'm happy to paint the inside and to treat
the outside (presumably after everything has had a chance to dry),
although I'd like the outside coat to keep the general look of
unpainted brick. For example I've just used garage floor sealer and
I'd be happy with that level of shade change to the brick but I
wouldn't like to paint the exterior walls a colour.
Reply to
Provide a shallow gulley by cutting a small channel into the floor to an outside point that can take the water.
Wait for some dry weather and waterproof the outside of the walls with clear silicon waterproofing liquid.
Reply to
On 2 Dec, 15:12, "" wrote:
Dear 86
The best practice is to render externally. However, you make it clear that you do not wish to do that so for the second problem I would use a stearate-based external brick water repellant and am completely against any form of silicone. Ideally, you want a layer that is water repellant but vapour porous not a water proof layer. For the first problem I would personally use Sika No 1 and render the part of the wall and floor causing the problem if I could not gain access to the outside but best solution is to ask your next door neighbour for cooperation (technically he is allowing a nuisance in law and you could force him but clearly that would be ott) and attack the problem at source. Consider a lead capping on the abutting wall, similar water repellant treatement and / or lowering of ground (if that is a problem) insertion of dpm between his abutting wall and yours etc etc Chris
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Thanks guys. I went to the local Focus to see what they had and spotted some Thompson's Water Seal which takes care of the penetrating rain issue. They do two kinds, the normal Water Seal (which seems to be a stearate-based one) and the Water Seal Ultra which is silicone. The silicone one does seem to last longer so I was wondering why Chris dislikes them so much for external garage walls. As long as the inside can breathe (and it's pretty draughty in there :) ), isn't that sufficient?
Regarding the garage/garden retaining wall issue, the two shed solutions seem to be: (a) Unibond Waterproof PVA mixed with cement and brushed on (b) That silicone Water Seal Ultra (although I see on the can it says "Don't use on garden rataining walls")
Has anyone used that waterproof PVA on a cellar or similar?
Does anyone know the reason why the silicone water seal says not to use on retaining walls - what would happen if I sealed the entire damp area? Is it something to do with needing to use a seal/render/etc. that is breathable to allow the bricks/mortar to dry? What would be the risk of sealing a 600*600mm section of the wall, bearing in mind that I'm happy with the small amount of water entering the garage, I just don't want it to enter where it can blow the cupboards.
I had a look at Sika but it looks too thick and bulky considering I only need to treat 600*
600mm of a 5000*2400mm wall. Thanks for the recommendation though.
Reply to
You might be being a little over optimistic there. If the brickwork is porous you'll get through gallons of the stuff and IME it might achieve nothing.
They do two kinds, the normal Water Seal (which seems to
SBR is much better than PVA, but also a good deal more expensive.
It's probably something to do with the possible build up of water behind a retaining wall, which could then freeze and.....
Reply to
Stuart Noble
On 3 Dec, 15:56, "" wrote:
Answer Any building operation to any part of it ideally should be reversible (William Morris Ruskin et al SPAB) or as close to it as possible. Silicone once on will not come off. It will not have a life anything like that of the building (200 years?) because silicone will degrade in say 20 years. You will then have a partial "water proof" layer with water going in faster than it comes out. This is true of oil-based paints on wood which is why wood degrades faster with them AFTER about 5 years than on microporuous paints. Brick operates on the basis of a dynamic equilibrium - absorbing water in the rain and giving it back after. You need to let it carry on doing this with a reduced not eliminated absorbtion Hence repellent not proof Chris
Reply to
Ah. Best give up on my plans to totally seal that wall then.
I've been thinking about the silimarities/differences between this situation and that of cellars. I suppose cellars, where they have been sealed, are underground and under a house, so the water never actually freezes. Looks like I'll be using some 1mm perspex sheeting to cover the side & base of the unit then and perhaps some of the breathable stearate-based sealer on the inside of the wall to try to stop the seeping. I guess I'll have to leave a small airgap down the side of the unit which were we live will turn into a spider factory.
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if the garden next door is higher than your floor then i'd get the nieghbour to dig a little trench on their side rather than dig a groove in your floor, or both, water loves to go downwards and will climb up a bit to do it...
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