Wednesday, April 09, 2008

Collapsed Decks

Sometimes decks collapse because of creativity.

This looks to most people like a good idea--few things are as strong as Polycarbonate.

Polycarbonate is a very strong plastic. The trouble is that every product will eventually meet their maximum level of usability. Most plastics do react with UV exposure and get brittle.

In this case they were overloaded to the point of failure. I found 3 broken clips...not sure how many there were.
These brackets were designed to hold the snow on steel or aluminum roofs rather than folks slamming the door and it landing on their heads.

Trouble is that they work very well. It keeps the snow on the roof... long enough to turn it to ice during protracted cold spells.

The ice builds up over the months and eventually the weight is too great--for the plastic snojacks in this case. If they were made of metal--it is not likely that they all would have failed simultaneously as in this case.

This was a deck that was sturdy enough for the owners to have a party on last weekend--and a week ago 2 or 3 tons of snow and ice slid off the roof and impacted the deck, punching the support posts up through the platform.

When a deck is just under built or a ledger fails the entire platform typically collapses.

Now, lets not rush to hasty judgement that the polycarbonate brackets caused the failure.

4 snowfalls with very little melt, protracted cold weather and a not so well insulated home causing the snow to condense into ice and a metal roof and a not so new deck all had a part in this deck failure.
This was in fact a fortunate accident.

Because this is the main entrance to the house.

No one was home at the time of the collapse.

L



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