Ok to Split Plywood (into halves or thirds) beneath Queen Memory Foam Mattress?

I live in an older house where I had a hard time getting my new memory foam mattress up the stairs and through the hallway. Luckily, the memory foam mattress allows for a bit of flexibility to bend around corners, etc…

However, I am currently stuck with a “split” boxspring from my old mattress. Split meaning that it’s basically two smaller boxsprings that equal the size of a Queen mattress.

Knowing that boxsprings are a no-no for memory foam, many have said to place a 3/4" piece of plywood underneath the mattress. Since I can’t fit one large sheet of plywood (even cut to size) up the stairs, can I cut the plywood into halves or thirds and still have it be effective? The few comments that I found online are conflicting; some say it isn’t OK to split plywood since it destroys the ability to distribute weight evenly…

I apologize in advance if this topic was already discussed. I searched up and down and couldn’t find an exact answer. Thanks in advance!

I think it probably depends what you are resting the plywood on. If you have even support underneath the plywood then you should probably be fine. Also, a full 4x8 sheet of plywood is too small for a queen mattress anyway. My setup is slightly different but here is what I did: I bought a steel frame off amazon- the typical 14" high one you see everywhere. While it’s pretty solid, I felt that in order to put a memory foam mattress on top I wanted a more even surface without the big gaps. Also, I’ve read it’s better to have some ventilation underneath a memory foam mattress so what I ended up doing was using melamine pegboard. Obviously it is think but when laid over the frame, I do not need much support from the boards. I cut the first piece to 60x48 and had that at the head of my bed. The smaller piece was then placed next to it towards my feet. Reasoning with that is 48" single piece would cover my torso and then some so even if there was uneven distribution between the two, it shouldn’t affect me. For added stability, the pegboard was secured to the frame with zipties. Hope this helps she’d some light on your question

Not sure exactly what you are trying to achieve with the plywood. But there is always the option of a Knock Down (KD) Foundation (similar to this one → Here), that I am not sure if you are aware of. It can be carried of the stairs unassembled in pieces and assembled in the room you plan on setting the bed in and disassembled if you choose to move it.

Hi Comp625,

I’m not sure which foundation TandL was linking to (it goes to a reply link to this topic) but there are some sources for KD (knock down) foundations in the foundation post here.

Just as some food for thought there is more about solid surface foundations in post #10 here.

If you put a solid sheet of plywood on a box spring it would provide good support but depending on the specifics of the mattress or the box spring it may still sway or tilt when you sleep on one side or the other or with heavier movements (particularly with heavier weights or weight differentials between a couple). As runnerb0y mentioned if you have a split in the middle under the heavier part of your body it could still deflect under your weight at the split. At the very least I would make sure that a split wasn’t under the heavier parts of your body (as runnerb0y also suggested).

Outside of ventilation … the goal is to have solid support under the mattress that is stable and doesn’t flex … particularly under the heavier parts of the body.


[quote=“Phoenix” post=30864]
I’m not sure which foundation TandL was linking to (it goes to a reply link to this topic) but there are some sources for KD (knock down) foundations in the foundation post here.


My apologies, I fixed the broken link. It is linked to the foundation that is sold by mattresses.net it is the only one I can attest to.