We have a small cantilevered deck off our 2nd floor bedroom, where the deck’s support members extend through the building envelope with no supports below. I recognize this is a less than ideal structure, but it was installed by the previous home owner 11 years ago.

We’ve noticed signs of moisture intrusion on the interior living space (to be expected with this deck set up). The joists are in good shape – just slight moisture-induced cracking/warping to interior drywall and hardwood flooring adjacent to the deck.

My question is: what’s the best way to address the moisture issues besides simply tearing down the deck or starting over?

My current plan of attack is:
1) re-insulate interior joist spacing behind deck with 6-8″ XPS foam board sealed with caulk;
2) re-flash deck joists using the approach described below in the FHB link; and
3) replace the deck flooring with Azek porch boards (which have minimal spacing between each board) to limit water drainage from the deck surface onto the joists. The deck joists are level, so installing the new porch boards would involve machining long angled shims to give the deck a slight pitch (am aiming for 1/8-1/4″ per linear ft).

Is this a wasted effort? As in, am I better off just tearing the thing down because there really isn’t a good solution? Or can I make something work effectively that will last 10+ years?

Many thanks in advance!

Flashing cantilevered joists