It stopped raining today after about a week or more and I've opened the obs to find the floor is wet. It appears water is being drawn into the obs via the concrete floor. Nothing else shows any sign of a leak so it's probably capillary, through the concrete. If fact around the pier footing you can see where water has been drawn in, between the floor and the rubber jointing around the pier footing, so it's also coming up from underneath.
I have installed that rubber flooring with the holes in it to soften the blow on dropped parts, but the holes catch any dirt and the dirt has started to turn to mold in some spots. So, I've pulled the rubber out, vacuumed and scrubbed the concrete floor and am looking to seal it better.
Unfortunately I can't lift the bottom ring which is sitting on the concrete to seal under it but I figure plenty of paint might keep the water from coming in and growing mushrooms
As I have lashings of acrylic paint on hand, will that be ok to use to seal the concrete or is there something special about acrylic concrete paint?