Prefab garage water ingress

I rent one of these at the moment and I have had to seal it at every joint in the walls and the roof. So now the rain comes in under the doors when the wind is coming in the right/wrong direction. I have used expanding foam, three cans of, and then cut it back when it's gone off. I'd advise that you do the same if you are having a similar issue. If it is coming in from below where you can seal it as suggested, dig away 6-12" and then seal it as suggested. Dig as far as you need to, to make sure that the water can drain away, and fill it with large gravel.

Most prefab garages unfortunately when put together do not have enough construction joint sealant installed between the panels and water will always find a way in for even a gap 1mm wide. It is often possible to re-seal it from the inside with a good gun grade silicone. Water ingress is often at the lowest point also so where the walls meet the slab it it advised to seal here also. If you are needing to dig down, i.e soil is up the walls it will always leek without properly tanking so may be very much a waste of time as concrete isn't waterproof (unless is a special mix) Pre-fabs generally are only waterproof if when installed on a good level elevated slab, and have been correctly sealed and also the bottoms sealed to the slab. Id try sealing the inside first see how that goes as its an easy DIY job, couple hrs and £30 max.

There are a number of answers, it depends on if you have concrete bigger that the brick building, then you would have to seal brickwork, but if the brickwork site on the edge of the slab , I would definitely put a drain around the perimeter, dig down 2ft around the perimeter and approximately 12 inch wide , put 4 inches of 40 washed stone in the bottom then lay 4 inch perforated drainage pipe in the centre of trench , then fill to ground level with the 40 washed stone .