Answer:
A experimental design could be applied in this case. The experimental design is a technique of research used to identify and quantify causes occurred from a specific effect during a experimental study.
In this case, the variable that cause something is the rain, and the study is gonna be focused on the effects, which are water damages. To do the experiment with this design, first we need to identify specific indicators to observe and measured, like material resistance, water damage, state after the causal variable is applied.
On the other hand, this design is not needed to be double blind, because that 's applied when the experiment consist in two groups with different stimulations, which is not the case here.