Natural stone cleaning and caulking on a Fort Worth facade
Heavy staining on the stone, and failed sealant at every joint behind it. Both had to be put right, in that order.
1300 Houston Street is a multi-level commercial building in downtown Fort Worth. Its exterior pairs a full natural stone facade with multi-level glass curtain wall, so stone, metal and glass all meet along the same run of joints.
What went wrong
Years of environmental exposure had left surface buildup and dark, uneven staining across the natural stone. From the street the facade read as patchy rather than simply dirty, which is what happens when deposits settle unevenly and then weather in.
Behind the staining sat a second problem. The exterior caulking had deteriorated at the stone control joints, at the window perimeters, and at the glass-to-metal curtain wall connections. Those are the joints that keep water out of the wall, and all three had failed.
Why the two had to be handled together
Cleaning stone while the joints are still open buys appearance and nothing else. Water keeps moving through the facade, carries minerals with it, and the staining returns. Sealing stone before it has been cleaned locks the staining in underneath. The sequence is what makes the work last: clean the stone, seal it, then close the joints.
What was used
Stone Restore CB2 removed the staining, mineral deposits and environmental buildup across the full stone facade. On the worst elevations it took more than one application, which is the difference between a seamless result and a wall of clean patches sitting next to dirty ones.
Leach Stop went onto the cleaned stone as the sealer, protecting it against weathering and against the water penetration that feeds mineral leaching in the first place.
The failed sealant was then cut out and replaced with high-performance silicone at the stone control joints, window perimeters, metal transitions and curtain wall glass-to-metal connections. The curtain wall glass joints were wet glazed to seal the glass into the metal framing.
How it came out
The stone reads as one consistent surface again, and the envelope is sealed at the joints that had been letting water in. Access was by lift equipment throughout, so the building never went under scaffold.
Products used on this project
- Stone Restore CB2 — cleaning the natural stone facade
- Leach Stop — sealing the stone once clean