Garage leaking

[Electric_Andy]

My garage is single brick, has been dry as a bone for 4 years. But back in November my gutter and drain became clogged and water pooled up the side and seeped in over the damp proof course. I cleared all the drainage but it's still damp coming in the bottom whenever it rains.

DPC is only.75 of an inch above the concrete base at the front, which is where it's coming in.

Any advice on what to do? Can't understand why it's been fine for 4 years, now drainage not an issue but still weeping in? Does DPC become less effective after it's been flooded through?

 

[Psamathe]

I'm no building expert but when I put in paving slabs beside the house slabs had to be a minimum distance below the DPC. Although slabs were outside the house, rain can apparently splash hence the minimum distance below DPC so it does not splash onto wall above the DPC and soak in causing damp.

Might this have something to do with your damp problem? Where I live we seem to have had a lot of heavy rain that goes on for days ...

Once water soaked into and through a wall I'd expect it would take a fairly long time to dry out (even without being replenished).

(I am no builder so only repeating what I found when doing my own works.)

Ian

 

[Buck]

The ground surrounding the garages is likely water logged and rain splashing up onto the brickwork may be breaching the DPC. Also, the bricks themselves may not have dried out properly so any sustained rain like we have been having is causing the bricks themselves to take on even more water and through capillary action the dampness is appearing. Potentially also a failure of the pointing ?

Check that there hasn't been a build up of debris (leaves, soil that's washed against the wall as well)

You can buy a brick sealer which if the pointing and bricks are in good condition can eliminate some of the problem.

 

[Electric_Andy]

had to be a minimum distance below the DPC

thanks, yes I htink this is definately the problem but it's next doors concrete drive so I can't do anything about it. It's just confusing why it's been fine for 5 years, then obviously flooded when the drainage was blocked, but now seeping in again

 

[Electric_Andy]

Check that there hasn't been a build up of debris (leaves, soil that's washed against the wall as well)

You can buy a brick sealer which if the pointing and bricks are in good condition can eliminate some of the problem.

Thank you, I have totally cleared the very shallow gully down the side which was the problem (and a blocked drainaway). I will look into a brick sealer as well, but I read somewhere that you have to do the entire wall inside and out for it to be effective. Maybe sealing the bottom foot would be better than nothing

 

[jowwy]

Thank you, I have totally cleared the very shallow gully down the side which was the problem (and a blocked drainaway). I will look into a brick sealer as well, but I read somewhere that you have to do the entire wall inside and out for it to be effective. Maybe sealing the bottom foot would be better than nothing

you could paint around the bottom of the outside wall with a rubber membrane, so water doesn't penetrate the brickwork.

 

[presta]

You can buy a brick sealer which if the pointing and bricks are in good condition can eliminate some of the problem.

I was toying with using some of that, but a surveyor at the council warned me not to. He said it's normal for walls to breathe and allow water vapour from inside the house to escape, but the sealer prevents this happening until the water builds up behind it and forces the surface of the brick to spall.

 

[Psamathe]

Injected DPC slightly higher? I'm no builder and just thinking aloud here and it may be a daft idea. I'm actually not convinced about injected DPCs anyway plus you'd still have the area between the proper DPC and the injected DPC.

Re: sealing: Remembering I have no experience, I have always though (as others commented above) that sealing stops a natural "breathing" process sealing damp in as well as keeping it out. So I would be very careful about special sealing paints (particularly as getting them off would be a nightmare if they did more harm than good.

Ian

 

[Electric_Andy]

Thanks all. I have the dehimidifer out there so hoping it's still damp from when it flooded, it's not actual water coming in anymore but the dust/silt on the floor by the wall still gets damp and it's "new" damp after a period of dry weather. Which at the moment is about 3 seconds. The up-and-over door is by no means air tight (there's a good 2mm gap at the top) so the breathing issue might not be as bad. I'll see what Farther says when he's well enough to come look at it

 

[Psamathe]

Couple of thoughts. Does the garage have significant footings and does the garage floor have a damp membrane. I ask as when I had my garage built I insisted it was built to building regs standard even though it was not covered by building regs. And builder asked if I wanted a damp membrane under the concrete floor - apparently some people do, others don't (I did).

If shallow footings and no membrane then maybe the flood saturated ground and now it's coming up through the floor? (in which case sealing the wall wont help).

As I said before I'm not a builder or similar so thinking aloud rather than suggesting cause/fixes (and very open to others saying I'm wrong).

Ian

 

[Electric_Andy]

No it's definitely coming in through the damp proof course. Neighbours concrete slab has been built up too high. Probably doesn't comply with any regs. 80s house so no idea