Here is my situation. I have a simple attached deck that is 6 feet wide running the width of my house. The deck is 8 feet off the ground. At its 6 foot limit are three teleposts carrying the deck weight (roughly 15 feet apart). All joists (2x10) are single including the joists running to the three teleposts.

I am replacing the deck surface and I would like to extend the deck out by 18 inches beyond the teleposts so it is a more functional space. Here is my plan: I thought I would replace each of the 3 single joists running to the teleposts with three gang-nailed joists that were 7.5 feet long instead of 6 feet.

I would leave the current double end pieces in place to accept the existing joists. Except where I have to cut to accommodate the longer triple joist piece; then a would build 2x10 frames each 1.5 feet wide. To fit the spaces between and the teleposts. I would nail/screw these securely to the triple joists and the existing doubled end pieces.

I would appreciate a response from an experienced builder to tell me if this is a safe plan or to provide any advice/options I should consider.

Thank you very much

Kurt Hall

the deck can only extend 2ft past the beam, for code that is.

usually we build a 2x10 or 2x12 beam that the end of the deck sits on and cantilevers past 2ft,
you could scab on to the joist already there and extend out further but its not code and id be curious to see how much flex or bounce you get at the end
you can just add other beam to the end for more support

You may also wish to add bracing from the poles to the outside joist at a 45 degree angle.