jl200

In the process of having a new flat roof laid. The first cement screed/base (using fine sand) was down and then 4 coats of the waterproofing product applied all over it. Then some small ventilation holes drilled to the outside walls to put small pipes (about the size of 5p coin) in for air-circulation about 10 around two sides of the roof. All completely dry and no leaks. Good so far. However, 5 Hours after having the second cement screed/base on top (this time using coarser sand). It started to rain. Will this cause a problem. Will all the new cement have to come up because there is nowhere