Forge concrete at an angle and place a galvanized sheet, bent on the back of the wall wave, and rivet it in the place where the wall is fastened so that water from the wall flows down onto the sheet and outside, not inside. Checked, dry inside - I also made a larger plate under the tin and the water was constantly leaking.
Bituminous masses, plastic stelae, e.g. Abizol G Tytan Professional, seal the entire garage around the perimeter - oki heat-welded roofing felt, but the walls are made of trapezoidal sheet metal and it will be difficult to place the roofing felt in the grooves of the sheet well
Quoting the poet "Water has it that it flows into the main river, to the Baltic Sea" - just convince her that flowing through your garage it will be uphill. A few cm of indoor floor is enough. I made a collar poured in the center around the perimeter of broken old asphalt, heated in a cauldron over the fire and a bit of a burner. But it can be concrete (the thickness of the profile that rivets the sheet)
I have a question. I have a tinplate, but no door (I have it reported as a lamp). There is a draft on each side (gaps on the sides and back of the garage), yet water collects on the beams under the roof on cooler days. How to control it, the car is drenched daily with zinc rain I read to stick with polystyrene or vapor-permeable foil, but how to stick these beams?
Okay, but what will you do by painting the angle bar?
Thread. More would be to remove the condensation of water vapor from physics. If the mixture of steam and air hits a partition which is colder than itself, then we have water. It does not matter if the partition is called a leaf, grass, beetle's wing in the desert or a tin plate. Heat the baking tray and the problem will disappear . You can, of course, cover the whole with a nanotube membrane and drain them properly, but the cost will "slightly" exceed the price of the tinplate.