Learn how to replace rotted wood cantilevered deck supports. Find out where to install steel I beams to safely replace rotted wood cantilevered deck supports.
Margaret in North Carolina is dealing with a nasty three-letter word: rot. Tell us about it.
MARGARET: Yes, we have a balcony and the balcony is 14 feet from the ground. The supports are wood and the wood has rotted out ; the wooden supports. And so what we’d like to do is the wall itself, the façade of the house, is brick and the wooden supports for the balcony go through the – into the wall, into the ceiling below, into the wood braces …
MARGARET: … that are on the ceiling. Well, we want to replace that wooden support with a metal floor on the – metal floor for the balcony – as well as metal supports; three metal supports that cantilever into those beams in the ceiling below – wood ceiling – wooden beams.
TOM: Right. So you have a balcony that extends out the exterior wall of your house. Are there any supports underneath or is it totally cantilevered off of the outside wall of the house?
MARGARET: Totally cantilevered.
TOM: OK, so you have a rot problem ; you’ve got a serious structural issue . Taking that apart and rebuilding it with steel is probably a good idea. You’re going to end up using steel I beams and you would only need two I beams, one at both ends, and then in between you could have wood floor joists; pressure-treated lumber. But the main supports that go through the wall and cantilever back over the exterior wall, they would have to be steel I beams. This is a big project; not one that you can do yourself; one you definitely need a pro to work with you on. You definitely need a good, qualified contractor  and you need to get a building permit because there are a lot of deck collapses  because of this very reason; because of those rotted beams that go from the outside of the deck, cantilever over the exterior wall and go back into the house. So you’ve got a big job on your hands but it sounds to me like you have the right plan.