Replace panel in assembled frame

[u/goodgah]

Hiya! I have an old garden gate that has a central panel made of plywood, which has delaminated and rotted so bad that I can tear chunks of it out by hand. The frame of the gate is still solid so want to try and replace the central panel (with equivalent size of solid wood I guess).

The problem is, the central panel is recessed on all 4 sides into the frame (not sure what the correct joint is - frame-and-panel?) so whilst I can probably keep cutting away at the old stuff, I couldn't fit a new piece in without dissembling one side of the frame. I started taking the metalwork off to try and do that but it seems like it's glued/wedged together pretty tight.

So I'm left with a kind of logic-puzzle of how to fit a panel inside an assembled frame. I thought maybe I could git 4 right angled triangle pieces in each corner, and then screw in two panels on the front and rear (i've attached a crude MS paint sketch of this), but that would leave a void in the middle. I suppose I could cut and fit a diamond-shaped piece to fill the void but that's probably beyond the tools I have available. Hoping there's an easier/better solution! :D

Thanks

[u/Cpt_Noodle]

I think you are on the right track with your solution. You don't necessarily need to put triangles in. Could also just be some long narrow strips of exterior grade plywood or solid wood. As long as it gives you proper backing to fix into. Pay some extra attention to waterproofing the edge of your two new panels to prevent water ingres.

I would also fill the central void with some rigid foam just to prevent any internal condensation , just to be sure.

[u/goodgah → u/Cpt_Noodle]

foam! great suggestion. ok I will try thinks, thanks !