3/4 Birch

No

Yes

18"

What about MDF?

Suggestions on the 'no'? Something other than biscuits, maybe?

The endgrain will hold without the screw disintegrating the plies?

18" height and depth?

Sure you can use MDF as long as you construct it so there isn't too much of a span. I use that quite often in panted window seat, just did one for a centry old home a couple of months ago matter of fact, made it easier to make & match the onsite made moldings.. I need to get those pics on my site, totally forgot about that one.

You'll want to design it so that the load is onto vertical gables, not into dados for example.

Yep.. it's done all of the time. If you are close to the end of the ply pre-drill. Pick up a counter-sink to match the screw, #8 flat head most likely right?

X 24" to the cushion or backrest, which is typically around 15 deg.

Great! Thanks for the info.

Span will be approx 2'-6" (No more than 3'-0") Still working out the dimensions.

Onw more question: what do you mean by vertical gables?

Thanks again.

Say if you wanted to have a part of the seat used for storage that you get to by opening the top. The top would be on a piano hinge & you would frame in the storage area with 3/4 uprights... they are called gables in cabinet making... the pieces that are up & down on the sides. So want those for supports, have a look at the cabs in the Kit. you'll see the c/t runs over the side and is supported by the gables... you'll be doing that same thing.

OK. So which is better, MDF or plywood? And as far as construction, what's the difference between the two, besides cost?

Will the 'endgrain' of MDF hold a screw, if I decide to go that way?

...just trying to get all my facts straight, I don't want to have to do this thing twice.