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Not every job has to be a major
job. If you act at the first sign of a problem you have more alternatives for finding a
solution.
 Such is the case of a intervention we
participated in for a building owned by a major Virginia healthcare
insurer.
THE PROBLEM
The joints that allow for the expansion and contraction of masonry walls are not just
important, they are critical to the very integrity of a structure. Equally critical are
the joints between masonry and metal, and metal and glass. This structure, an independent
consultant found, had some significant problems with both types of
joints.
The consultant's analysis revealed
that the masonry expansion joints were improperly constructed, and that because they were
too narrow, the original sealant was split as the joints expanded and contracted during
temperature extremes, resulting in leakage to the interior and damage to the interior
finishes.
THE SOLUTION
The first stage was to enlarge all the masonry joints smaller than 1/2 inch to
approximately 3/4 inch to accommodate movement. Then, to reseal the joints using Dow 795
Silicone Sealant--a low modulus sealant capable of withstanding expansion and contraction
in temperatures between -20F to +120F.
With that done, we power washed the
masonry to remove surface contaminates and applied Chemtrete BSM 40 Silane Water
Repellent--a repellent that reacts with the alkalinity in the surface to make particles
water repellent. And because it reacts within the surface, it is not
affected by ultra
violet rays.
In the second stage we completely renovated and sealed the joints around the window
units--on the metal to masonry joints we used Dow 795 Silicone Sealant, on metal to
glass--Dow 1-2-3 Sealant.
Putting it to the test
 Next, an independent
testing agency employed by the owner, will perform a final test. To do it, they will
build a polyethylene tent inside the window and pull the air out with a fan. That will
create enough negative air pressure to show (when water is applied to the surface with a
spray bar) that there is a solid seal. In technical terms this air infiltration ASTM test
E28383 will demonstrate there was no water penetration evident with a pressure
differential of 12.0 psf.THE
RESULT
A serious problem was identified and corrected before it escalated into significant
interior damage.
To learn more about Richmond Primoid and the wide range of work they do, call
804-644-4561 or toll free 800-235-4561. > TOP
MORE CASE STUDIES
P.O. Box
6785, Richmond, Virginia 23230
Voice 804-644-4561 Toll-free 800-235-4561 Fax 804-225-7271
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