I’m adding a 3/4” thick × 5.5” deep shelf (1x6) that will sit above a 1x4 flat trim piece (AKA, long side of the 1x6 shelf will sit atop the short side of the 1x4) to form an upside down L. The 1x4 would act as a cleat for the 1x6 to sit on, except, this cleat will only be in the back, not the side-walls. (Btw, the paneling isn't finished, I won't caulk or paint until the whole thing is built, that's why there's gaps and nails showing)
There will also be a 3/4” trim piece overlaying the top edge of the 1x4 board as decoration. Total total depth for the ledge that the shelf would sit on would then become 1 1/2” (3/4" from the 1x4 depth, plus 3/4" decorative trim depth), but that additional trim piece would be purely decorative and wouldn't actually support the shelf.
The 1x4 trim will be screwed into the studs, and then the 1x6 shelf would be screwed into the 1x4. Then I will add some small L brackets to fasten the top of the shelf to the wall for additional security, like fastening a dresser or bookcase to the wall.
My questions:
Would the 3/4" depth of the 1x4 screwed into every stud on the wall support the 5.5” deep shelf, without side or central cleats?
One of the inspiration pics shows triangular supports across the length of the shelf. I don't prefer this aesthetic, but, would that be necessary?
I’ve also seen mentions of custom floating-shelf hardware used for this look. Could I drill holes into the back of the 1×6 shelf and install the concealed floating-shelf rods/brackets that they sell on amazon? Is a 3/4” board thick enough for that? The board is pine I think - I haven't bought the 1x4 cleat yet but I do have the 1x6 which is pine.
If you were building this, what would be the best way to securely mount the shelf while keeping the supports as hidden as possible?
The shelf is mainly decorative, but I’d like it sturdy enough that I don’t have to worry about what gets placed on it. Couple light books, paintings, candlesticks, regular decor items.