Anybody know about damp proofing???

Evening all,

So I have an issue in my garage which is getting damp at the back on the floor and walls. I’ve tried coating with Black Jack DPM. I’ve also tried these chemical dry rods, but don’t want to keep throwing money that I don’t have at it. It poured it down last week and when I went in there, I had standing water across the back.
The roof and guttering has been replaced recently, not necessarily because I thought that was the issue but because it needed doing. My next door neighbour’s son is a builder and he had a look at it. He reckoned the whole concrete floor would need to come up, new DPM laid then relay concrete again. He said it’s coming up from the ground. Reckons it’ll cost in the region of £2k !!!! I certainly don’t have that kind of money.

It’s making me feel quite anxious now, especially as we’re moving into Autumn. My Dad mentioned that I could maybe dig a trench outside at the back wall down to the footings. Lay in a DPM and drain pipe, then back fill it. Think they’re called French drain or something. I’m not the greatest at DIY, but maybe I could give it a go if I thought it might help. I’ve lost count of how many YouTube videos I’ve watched regarding this matter, and as always there a myriad of suggestions and solutions to the problem.

Wondering if anyone on here could offer up some suggestions on what steps I could take to try and remedy the ingress of water that I’m currently experiencing. TIA…………..

 

Dig a trench.

 

The ‘French drain’ suggestion is worth a try, assuming you have soft ground/soil to that elevation (which if you do, maybe just try and lower the ground level towards the wall as it may simply be soaking through) and make sure the drain pipe you use is slotted/perforated and wrapped in a cheap weed membrane.
Another possible’quick fix’ , if it is a single skin building, would be to just coat the brickwork with a cheapish waterproofer such as Thomson’s Waterseal.
The dry rods would only stop rising damp in the masonary whereas yours is likely to be penetrating damp.
Good luck with it.
Oh, and dare I suggest maybe a line of Aco drains in front of the garage door as the water could simply be weeping beneath the door and gathering at the back of the garage.

 

It’s dry as a bone towards the front, but know what you’re saying about the drains. It is only a single skin garage and Dad did say about using Thompson’s as well. Might give the trench at the back a go and see how it goes. Thanks again for your help.

 

And I always thought you worked in insurance.

 

Rather than dig all the floor up, cut a hole and put in a sump pump.

 

Sounds like the water table is higher than your garage.

 

Is the outside ground level higher than the concrete at the back ? If so dig a channel about 300 wide down to the concrete level and let the bricks dry out for a few days before painting the outside with a bitumen primer and then stick a flashing tape to it (comes in various widths depending on what you need, Wickes sell it and the primer) then put a visqueen against it before back filling with gravel or pebbles, did this on my garage years ago and never had damp since, it's all work that you can do yourself so not too costly. At no point should the ground level outside be above the concrete, good luck.

 

Thanks for sharing. What is a Visqueen btw ??

 

I'm a building surveyor. Do you want my email number, you can sent me photos and I'll help you. I mainly work with historic buildings but I can help with most things. I'm happy to help a fellow red.

 

That would be great if you’re sure. I’ll PM you.

 

I was going to say that the front is higher than the back with the water accumulating in one area. If it was the water table the whole floor would be wet.

 

Just a sturdy plastic sheet that would give an extra layer of protection from water passing through the wall.

 

I have some plastic DPM, so I take it that will do the job?

 

Pass me the visqueen please?

 

Haha, clear the shelves of extra wide ones

 

Only you

 

Yes, that's the type of thing.
Hopefully the water is just passing from the soil through the brick and not up through the concrete base which would be much harder to remedy.

 

Not always, depends also if the ground is higher outside all way round.
I have a precast concrete garage and the back always got wet but not the front because the ground at the back was higher than the garage base but the front of the garage was higher.