We recently (3 months ago) had a patio door installed in our house by a certified Anderson contractor. While everything seems to function well, in one corner of the patio door, we noted a tiny leak. We never saw any water coming into the house (even with very strong rain), but it's apparent that some water is coming through because of the water stains.
Picture 1 shows the inside of the house zooming onto the leak. While the dry wall is now up, the leak is not happening from above the patio door -- I think it is coming from the sill outside (picture 2). The sill on the outside is wooden. We tried to seal up any gaps with latex sealant.
I assume that the contractor installed and sealed everything properly for the patio door but I am wondering how we can eliminate the problem. Could it be that the sill is wooden on the outside and we should put vynal cover on top?