Structural PSA #6: Live in a Condo?

If you live in a condo building where you are responsible for your exterior windows and doors, make sure to determine what type of demising wall (wall in common with the units next to you and the hallways) you have. The problem with protecting a condo unit, individually from your neighbor and the building as a whole, is that typically the demising walls and entrance doors are designed as interior walls & doors and are not adequate to sustain strong forces. That is, unless your demising walls (such as in some townhouses) are a structural fire wall or shear wall. Therefore, if you protect your unit with impact windows and your neighbor does not, more than likely your demising wall in common with them will fail, as well, should they lose a window or door in the storm. The interior walls are designed to support only 5 pounds per sq. ft. whereas wind forces for a condo can be in the order of 50 to 130 pounds per sq. ft. If your neighbors windows fail that would introduce large positive pressure, debris and water which will affect everyone on your floor and most likely introduce water to the units below. Should this happen, the safest place in the building would be the stairwell which is typically solid concrete or masonry all around. I would not worry about the roof, per se, as flat roofs in condos are typically of reinforced concrete. Condo buildings need to design for such occurrences holistically and protect the entire envelope. Do not think just because your unit is protected with impact windows and doors, that you are safe during a strong storm.