Re: [GBlist] windows - seal failure

[FUnger@aol.com]

All insulated glass seals will fail over time. The only question is how much 
time. The primary cause of failure is water around the edge sealant, but the 
other causes discussed already also come into play.

The best way to prolong the life of insulated glass is as Steven suggested, 
always set it on rubber setting blocks and  provide drainage in the sash or 
glazing system. Also, specify "dual sealed" glass when ordering insulated 
units. These units cost a bit more but utilize a two step approach for 
sealing with silicone as a structural seal and another material like 
polysulfide as a primary moisture seal. They last longer and have better 
warranties.

In windows the answer is using good manufacturers. Cheap windows use lousy 
glazing systems typically. 

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