I'm trying to build a bed frame similar to the one shown below.
I'm struggling to design the long, chunky white support beneath the top bunk.
It looks like its about 200cm x 18cm x 8cm.
For such a long structure, I've thought about using two softwood CLS beams glued together with MDF boxing, but this seems fiddly and I wonder how strong it would be with a child jumping on top of it. I imagine CLS beams flex quite a bit and any mdf boxing around it may crack as a result or the glue may break.
Then I thought about maybe using 3 layers of 25cm birch plywood glued together vertically to create a single smooth beam which can easily be routed on the corners and painted easily without the need for boxing. Although this much plywood sounds a bit heavy, but think it would be very strong for the weight in the vertical axis at least. It would be supported horizontally to the wall, so I'm not as worried about horizontal or sidewise movement.
I couldn't find many examples of creating un-supported boxing like this on the internet.
Does anymore know of a better/best way to create long but strong structures like this?
I'm just interested in the long horizontal beam and not about connecting it to the other bits at the moment.
Thanks
Best Answer
There is not a convincing reason this has to be any sort of box structure. In fact for a bed support like that a single USA type of 2x8 (actual 1.5"by 7.5" 38mm by 190mm) on edge on each side of the bed would be way more than enough support. The overall weight can also be accommodated by using proper means to join the ends to the vertical posts.
If you like the wider top surface of the beam next to the side of the bed then that could be easily attained by using two of the typical 2x8s side by side or spread them a small amount and then cap the top and bottom with thin plywood. MDF would work for the cap too but is going to be more susceptible to damage over time if it gets wet.