Thread: Building a tatami platform bed, need advice about its sturdiness

You can use The Sagulator – WoodBin to calculate deflection in your merbau slats - but I don't think you'd have an issue using 19mm decking timber, your design looks like a fairly standard slat bed, and a lot of the time slat beds are sold with pine slats. Radiata pine has a modulus of rupture of 81MPa and merbau is 147MPa.

Happy to be corrected here but I reckon as long as you aren't jumping on the slats, you should be ok. If in doubt, maybe use wide 140x19mm decking boards?

Looks good.

I think there is generally a vast overestimation of the strength needed for the slats. 19mm is huge.

Son has an Ikea bed, second hand, the slats are clever. They are laminated pine made in bows. I couldn't guess the diameter of the curvature, but Id say they deflect about 20mm in the centre. I think they were 4 layers and about 8mm thick and perhaps 40mm wide.

The bowed slats offer an excellent support to the mattress.

They are obviously a lot more work.

On the bed design, those castellated joints are very trendy. Love them



...
Let me find a post I saw on Instagram that showed how these can be locked together.

edit - this dude Ursus Workshop
edit - and here Lock pins
edit - and here Laminating/veneering edges

Thanks for your replies, judging by what you guys said, I think I'll stick with the Tasmanian Oak and Merbau - just incase I jump on the bed without thinking or something like that.

Two observations:

1. The bowed Ikea slats are clever, but weak. I've had them break under normal use loads several times... Conversely my guest room Ikea queen size uses 18mm thickness pine, spanning half the width, with a central longitudinal divider - solid as a rock: these are very similar to decking pieces in appearance.
2. My self-made personal queen has pine 70 by 35 bearers, because they were the cheapest strong option I could think of - you don't see them, so who cares how ugly they are? (it's quite an elegant beech shaker bed in appearance). if you have the depth at the sides, this would be a bomb proof alternative for 'accidental jumping' or anything else... I'm 96kg, and hate weak beds. Ours sometimes has me, my wife, our teenage daughter and 2 dogs all on it at once, normally involving much laughter and chasing/jumping going on as we are assaulted first thing in the morning: zero deflection, zero worries.

My king size brass bed has Tas oak - actually mountain ash (Eucalyptus regnans) - battens 19mm thick x 1800mm long under a conventional innerspring mattress. I weigh around 100 kgs; my wife does not have a weight!

After 37 years => no problems! No visible sagging or breakages or splitting - although I have been told we need a new mattress.

Originally Posted by GraemeCook

My king size brass bed has Tas oak - actually mountain ash (Eucalyptus regnans) - battens 19mm thick x 1800mm long under a conventional innerspring mattress. I weigh around 100 kgs; my wife ...

same here
except our bed is queen sized.
The Tas Oak slats span the full width. Are 19 x 100


solid as



Note Tas Oak is supplied quarter sawn, so te grain essentially runs top to bottom of each board