Hope that this is the right forum for woodworking design critiques. I'm experienced with plywood but this is my first time attempting 'sturdy' furniture. I'd like to make sure it's going to be strong enough to hold up. As it's a Q+A site, the main question is: Is this design strong enough to function as a regular use dining seat? I can separate in to separate questions if appropriate.
Sourcing reasonably squared lumber is surprisingly difficult but my local depot has what looks like decent planed pine @ 44x69x2400mm that I'm considering using.
There's a few considerations to the bench design:
- It needs to be self supporting as I can't attach the frame to the wall. The wall is clad with 100mm insulation board and I can't drill through to the brickwork. I will certainly put 'noggins' in to keep it held against the wall to stop it rocking. There are walls on the back and both sides.
- I can only screw in to the floorboards but no deeper as there is underfloor heating below the floorboards.
- I've left the bottom open at the front because we want to make deep pull-out storage drawers on castors for toy storage.
- I'm planning on cladding the frame with 12mm birch plywood and using 18mm birch plywood for the top.
- I'm assuming we will seat a max of 4 people on this so worst case ~400kg load spread across it.
- I'll be using 18mm birch ply for the lids / seats. I've allowed for a 34mm overlap on 3 sides of each lid and a slight overhang on the front to easily open the lids. I'll secure with piano hinges at the back and use pistons with soft close for holding the lids open.
- I'll use pocket hole screws and glue for the joinery
- As I discovered when installing the kitchen cabinets, the floor is far from level, I haven't yet figured out how to compensate for this. The floorboards run from front to back on the window seat.