Q: I have an above ground sun deck that is half over my garage and half
over the driveway. The deck has a torch down covering with stamped
concrete on top. The problem is it leaks at the seam against the
stucco house, it is a slow leak as I have put caulking along the seam,
the caulking sticks wonderfully to the stucco but not to the
concrete. I have had tradesman come and look at it and their
recommendation is to redo the deck at a cost of $4500.00. Is there a
product out there that will allow the caulking to adhere to the cement?
A: It sounds as though the contractor did not put in place a metal counter flashing at the time the deck was installed. A 90-degree metal counter flashing would be cut into the stucco (this is called saw kerfing) caulked and then placed under the concrete or vinyl decking giving you the best water seal. This can still be done but would require a professional service trade to do so.
In the meantime, you may want to try Poly Urethane caulking. It will stick to both types of surfaces. You may have to re-apply every year in order to seal the joint.