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Wayne Carlisle
09-17-2008, 11:30 AM
Just had a councilman come by and ask me a question about windows. He owns a condo close to the Houston Galveston area and a friend of his said that the reason windows blow out is because the force of the wind "bends" the window inward and that is what blows the windows out!

It makes sense but I thought it would be more from flying debris.

This same person stated he installed 2X4's with carpet on one side of the 2X4 vertically in the middle of the window and he didn't have any windows blow out!

If this were the case then a true 6 over 6 would do the same thing. There would be a metal/wood center piece to keep the wind from bowing the glass in.

I'm just looking for comments on this because I don't have a clue on what the answer should be!

Jerry Peck
09-17-2008, 12:06 PM
Just had a councilman come by and ask me a question about windows. He owns a condo close to the Houston Galveston area and a friend of his said that the reason windows blow out is because the force of the wind "bends" the window inward and that is what blows the windows out!

It makes sense but I thought it would be more from flying debris.

It is *both*.


This same person stated he installed 2X4's with carpet on one side of the 2X4 vertically in the middle of the window and he didn't have any windows blow out!

Guess he did not get hit by air borne debris, just wind pressure.

Impact resistant windows are laminated so they can take the hit by wind borne debris and stay in place, and a major part of 'staying in place' is that the glass not only has more "bite" around it where it is held to the frame, but that the glass is basically either "glued" to the frame with sealant or mechanically "squished" between to frame pieces creating a lot of friction force holding the glass in place.

If regular windows (non-impact windows) were made like impact window, just with regular glass in them, the regular windows would withstand more pressure before blowing out.

Instead of going to a "true" 6 x 6, get an impact window and put one of those faux 6 x 6 mullion frames in front of it. That way you do not have one of the 6 x6 panes come out when it gets hit, plus, you have a lot fewer sealed edges to leak under all that wind pressure.

After Hurricane Katrina came through South Florida before heading to New Orleans, I had many previous clients in high-rise condos who had 'wind pressure' blow out was had previously been considered small projectile impact windows - 1/2' thick fully tempered glass. Put that in a frame the size of a 8 foot tall sliding glass door, make it 5-6 feet wide, and the 'wind pressure' bowed the glass enough for the tempered glass to shatter (that what tempered glass is supposed to do -right) and the entire sliding glass door glass imploded into the rooms, bedrooms, living rooms, dens, every room. From about the 12th floor up to the 26th floor (top floor), on all sides of the building, on almost all buildings.

When I called and talked to the Building Official about those supposed to having been impact resistant, he said: "They were impact resistant. At least what we considered to be impact resistant before the hurricane, now we know better."

What a way to learn. :eek: