Damp garage - tanking query

[Funtimes]

Hi all,

I have an garage at the back of my house that is very damp, the water seems to be coming in at the back which is a retaining wall and on the left hand side which is right next to my neighbour's garage with a small gap inbetween about a foot or slightly more.

The garage roof was refelted along with some barge boards down the side next to my neighbours garage about 5 years ago but the water still came through the side so I would say the roof itself is sound. After seeing the mass amount of mould and algae on it I thought it was time to do something about it.

There was a load of rubble and junk down the side of the garage up to the roof level, I cleared as much as I can (about 2 feet deep) as I thought it was bridging the damp, its a single brick garage but whilst digging down I found the side has another set of bricks but doesn't go all the way to the top.

Someone has also poured concrete down there in the past so I can get down any further. I was looking at tanking it along with putting down a liquid DPM and self levelling screed above it (floor is not that perfect) but after looking at Vandex BB75 it says that I need to render the walls first. I'm not that confident in my abilities at rendering whereas tanking with a brush didn't look beyond my capability.

Is this a standard practice that tanking has to go on over render? If not can anyone please recommend a tanking slurry that doesn't need a coat of rendering applying to the wall first?

Cheers

 

[tomfe]

Have you got guttering the garage roof on the boundary?
If you do, where does this drain to?

 

[Funtimes]

Hi Tomfe, theres no guttering on my side. Is this a better place to start than tanking?

 

[Notch7]

If there is a gap between the 2 garages and a fair of rain water gets down, I would start there.

Guttering or something to direct it onto your roof and away into a downpipe.

Im not sure if your mean tanking inside the garage -thats not the best place to stop damp getting in -best to stop it penetrating initially.

 

[Funtimes]

Hi Notch,

Thanks for that I'll have a look into it guttering, the boundary side does get a good battering when it rains. I was thinking of tanking the inside based on not being able to do much to the outside of the wall due to the smal gap on one wall and the other being a retaining wall, completely understand your point about stopping it getting inside in the first place. Cheers.