Garage DPC Passing Water Thru Wall

[Chris Beesley]

HI Guys,

I have a problem with my garage ... it was built with the house around 35 years ago - when it rains water is leaking thru the walls into my garage. The DPC has been laid straight onto the concrete base then the first layer of mortar on top... its this that is letting the water in, is there anything I could do to solve the problem? Maybe a waterproof render inside/outside of a few inched high?

 

[Frederick]

You could consider tanking the walls up to a height of 30cm above the last signs of water ingress, remembering to extend the tanking onto the floor (at least 30cm, but preferably the whole floor). The obvious choice would be a cementitious slurry such as Vandex, although this will not provide a trafficable surface if extended onto the floor. Another option would be to use an epoxy coating. Good quality epoxy coatings (ie those containing pure epoxy and not cut with cheap fillers such as silica flour) should provide ample waterproofing whilst providing a trafficable surface.

 

[PatrickD]

Would it be possible to lower the ground level by a couple of inches in the vicinity of the dpc? Perhaps a small trench or similar?

Patrick

 

[JohnD]

Rather than working on the inside, surely the outside wants protecting? Is there enough of the raft extending beyond the wall to add a dwarf wall, or apply a coating to the lower part of the wall and the raft?

 

[Nige F]

As JohnD said........I had same prob. and just flooded the cocrete and first 2 courses with Grangers....in the summer From the outside

 

[Chris Beesley]

The problem I have is one exterior wall of the garage cannot be accessed as next doors garage is built so close (there is about 6" gap). Can anything be done from the inside? I was thinking of a seal similar to silicone used on a bath but wider...

 

[JohnD]

hmmm, so where does the water come from? Is there a leaking gutter?

 

[Chris Beesley]

Behind our house is a large field/hill it happens after each downpour - i think it is working its way through the soil as our garden gets a lot of surface water. At the top of the field used to be a large wood but they cleared it to make way for housing. I was hoping somebody would have an idea similar to using a sealent/goo? for around the dpc forcing the water around the exterior of my garage instead of through it ... any ideas?

 

[JohnD]

I think Patrick had the best idea, excavate a small trench round the concrete raft and run it away from the garage to drain. You could fill it with shingle so you don't trip in it. The narrow gap would be the worst prob - if there is a build-up of rubbish between the two garages, scrape it out as best you can. The idea is to have the soil level below that of the concrete raft. You might need to dig a soak-away at the accessible ends of the gap. Provided both garages have gutters, and they don't leak, that ought to help a lot. If surface water is running into the gap from the garden, maybe a slate dam would prevent it.

If you are going to waterproof the base of the walls, it would be better done from the outside where accessible - an asphalt or fine concrete plinth raised from the concrete and a couple of courses up the wall, then treat with a waterproofing liquid. I imagine if you scrape the soil away you can see the edge of the concrete with the bricks on top - how far does the concrete project beyond the brickwork?

I have heard of epoxy coatings being used inside basements, you will need a very sound surface or it may get pushed off.

 

[suffolklad]

hi if you are getting flood water because of developement id contact the council the development area should be drained u shouldnt suffer because of it