Water penetration into garage

[71silverfox]

We have a detached garage, which is situated under the terrace of our house (I have attached a picture).
We want to make it into a useable space for music and recording so have started to get it ready. Unfortunately we are encountering quite a few issues with water....
It started off with a good few inches of pooling at the back of the garage, but no clear idea of where it was coming from. The concrete floor did slope towards the back of the garage, and it would only take a day or two to fill back up.
So we screeded the floor, which seemed to stop the pooling - result!
We also remortared round the top of the garage to ensure no leaks.
We also tank slurried all the internal walls to prevent any moisture coming through the walls.
We thought this had done the trick, but this morning all the walls are wet through inside - which actually looks like condensation now.
We are planning to board the walls, but worried now that the condensation if not sorted will just cause more problems..
The garage is brick and concrete floor and roof (terrace over garage).
We are really struggling as doing the work ourselves - please can anyone help or advise?
Thanks, Darryl.

 

[freddiemercurystwin]

Better photos would help, those are dreadful, what's going on down the sides and at the rear? Where is the ground level in relation to the floor level?

 

[71silverfox]

To the right is a stone wall - separating our boundary and next door.
To the left is stairs leading up to the house, and to the back is under ground. So it's basically like a basement....
I will upload some better pics shortly..
Thanks

 

[71silverfox]

 

[Ivor Windybottom]

You're wasting your time trying to keep the water out with a coat of magic goo.

Tanking is just for showers, to keep water from going from the room into the wall. It's not capable of keeping water in the wall inside it, that's just not its intended purpose.

It needs to be treated like a basement, ideally with a separate inner wall and drainage. Or there are various treatments involving dimpled plastic sheeting.

It will also need insulation. The condensation may just be because the wall is colder than the room, so moisture from the air is condensing onto it. Again, magic goo will not fix this - it needs insulation.

 

[71silverfox]

Every article we read said that tanking slurry was the best solution to damproof basements and prevent water ingress....
If we were to treat the walls with the dimpled membrane - will this cure the problem? Can this be boarded over with plasterboard?
I'm trying to do the best i can, and dont have a massive budget to get experts in unfortunately.....

 

[George_engineer]

You need Type C waterproofing if you want it any way habitable.

 

[freddiemercurystwin]

Every article written by the people who sell it no doubt. Problem with slurry's is there's no way to find out if they'll work or not, sure they will work in some situations but if the water pressure is too much they're useless. A dimpled system can be dot & dabbed over, alternatively you build an independent stud wall a little away from the dimpled membrane and insulate/board that. But it begs the question what's happening with the roof - is that waterproof?

 

[71silverfox]

I've just looked at type c waterproofing - looks great but very expensive, i just dont have the budget..☹
I don't need it habitable, just dry so we can use it to store equipment and use as a studio (I'm going to soundproof if).
Any (inexpensive) ideas would be welcome....
The roof is concrete, and so far - is not a problem..

 

[JohnD]

please draw a sketch showing, for each wall and the floor, where is the adjacent ground level

it looks like you have a semi-basement in wet ground

 

[freddiemercurystwin]

please draw a sketch showing, for each wall and the floor, where is the adjacent ground level

it looks like you have a semi-basement in wet ground

You can see where the ground is from the photos.

 

[Ivor Windybottom]

I'd check the roof, given that it looks to be wettest at the top.

Also check what happens to all the water from the roof in that concrete trough, have a look while it's raining heavily.

It will never be anything other than damp though, you can't make a silk purse out of a sow's ear.

 

[George_engineer]

I've just looked at type c waterproofing - looks great but very expensive, i just dont have the budget..☹
I don't need it habitable, just dry so we can use it to store equipment and use as a studio (I'm going to soundproof if).
Any (inexpensive) ideas would be welcome....
The roof is concrete, and so far - is not a problem..

Unfortunately water is very good at getting places you don't want it. It's basically a cellar and there aren't any easy get outs.

Permagard / Permaseal generally seem to be the cheapest you can get.