Concrete compton garage leaking

Kevmanfred

Morning all, so I have an old sectional concrete compton garage attatched to my house that seems to be letting in water any time it rains heavily. 
There is no flashing between the house and garage and water gets in there but it also seems to be coming in from underneath and the sides, as well as through the old asbestos (I  believe) roof.
Now I really don't want to have to pay for an entire new garage, including removal of the old one, can anyone recommend anything to stop it as maybe a short term fix, special sealer perhaps? Me getting on the roof wouldn't really be an option due to the asbestos roof not being strong enough to support my weight. 
Thanks in advance for any recommendations or solutions.

grumbler

Except the leaking roof, it's absolutely unclear to me what "coming in from underneath and the sides" means.

Even if it were possible to stop the roof leaking, it's unrealistic to do this without getting on it.

Kevmanfred

grumbler said:

Except the leaking roof, it's absolutely unclear to me what "coming in from underneath and the sides" means.

Even if it were possible to stop the roof leaking, it's unrealistic to do this without getting on it.

It looks like the majority of the water is getting in where the bottom of the concrete sides meet the floor if that makes sense?
I suppose I was hoping there was some kind of waterproof sealer I could use from the inside but yeah it does seem unrealistic without getting on the roof.

grumbler

At the bottom, IMO, any leak is better to stop with a strip of mortar outside.

Kevmanfred

grumbler said:

At the bottom, IMO, any leak is better to stop with a strip of mortar outside.

There is only a tiny gap between my garage and the neighbours, who has an extension, which is probably the reason the previous owner hasn't done anything about it. 
I might have to bite the bullet and just get a new one unfortunately, I know the garage has been there a long time.