# Loft Bed Joinery



## percent20 (Feb 8, 2019)

This is going to be my first "big" project, and am looking for some guidance. I am making a loft bed for my children.

I have never made anything where I needed to be concerned much with wood movement, and I am not sure if I should be now. I am going to be using poplar.

My main question is do I need to worry about it? part of me thinks I don't need to, but I am not sure.

My other question is I mainly plan to use dowel joinery for all of the slats, and some sort of breakdown hardware for the long side rails into the main structural ends.

Then for the entry opening maybe do a long half-lap.

Am I on the right track or have I maybe missed something?

Here is my design, so far.


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## CWWoodworking (Nov 28, 2017)

The rails seem a little small. This maybe just the picture. I would aim for 6-7".

The corner post might extend slightly too far above the top rail. There is regulations against this. Some wouldn't care. That's up to you. Its very close so not too big of deal to adjust or leave.

It looks like you have slats for the mattress support? If so I'd change that to a solid piece of plywood.

The joinery sounded good.


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## percent20 (Feb 8, 2019)

> The rails seem a little small. This maybe just the picture. I would aim for 6-7".


Thanks for that. I was debating on that. I definitely will up them.



> The corner post might extend slightly too far above the top rail. There is regulations against this. Some wouldn't care. That's up to you. Its very close so not too big of deal to adjust or leave.


I will check this out.


> It looks like you have slats for the mattress support? If so I'd change that to a solid piece of plywood.
> 
> The joinery sounded good.
> 
> - CWWoodworking


I was debating between slats and plywood.

Thank you for all the advice.


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## Bstrom (Aug 30, 2020)

There's a rule about the space between the railing stiles - gotta keep that child from getting his head stuck in there! Study crib designs and you'll see how this dealt with…


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## percent20 (Feb 8, 2019)

> There's a rule about the space between the railing stiles - gotta keep that child from getting his head stuck in there! Study crib designs and you'll see how this dealt with…
> 
> - Bstrom


Thanks will do. That is another area I was thinking about increasing is the number of them.


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## CaptainKlutz (Apr 23, 2014)

+1 There are standard CPSC safety rules 'SAFETY STANDARD FOR ENTRAPMENT HAZARDS IN BUNK BEDS' (CFR Title 16, Chapter II-B, part 1213) on commercial loft beds for height of railing above the mattress and opening between the rails. It is a good guideline to follow for DIY.

Not many wood movement issues with bed, following standard design shapes.

If the bed support slats are solid wood, the only challenge is leaving little space for width expansion. 
Use engineered lumber (plywood) for deck and you don't really care.

In the what I have I forgot dept:

The choices made on HOW bed breaks down for transportation will impact joinery more than any other factor. As fitting the assembled bed through doorway into bed room limits the size of major pieces.
Unless bed is built in the room as permanent fixture; will need to use fasteners, or wedged/pinned tenons to allow break down to smaller pieces.

Some designs have the bed(s) separates from supporting leg frame. Other designs the bed is assembled in tall vertical halves, with sides firmly fastened together. Same challenge either way; how to assemble and maintain strength.

Don't plan on it being a family heirloom, unless you have a lot brothers/sisters with kids. Kids seem to grow out of the desire for loft beds in 2-5 years. Check CL if you want confirmation.

Suggest you over design the structure to hold weight of 2 adults or ~3 children bouncing up/down on it during a sleep over. Worst case might need to handle the classic clown car game: 
How many little girls can fit on this unbreakable pink loft bed that dad built, while mom is popping the popcorn?

Answer: My last creation supported 10 little bodies till wood started cracking, and they all decided to jump off. 
Daughter has never slept in any loft bed again, not even at camp; and shes an adult now. Yes, I have a family of Klutz.

Best Luck.


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## JohnMcClure (Aug 24, 2016)

I built a very solid bunk bed from maple. You may draw some inspiration on knock-down joinery, dimensions, etc from this project. 
I have 3 kids, and I've been on the top bunk with the 3 of them and never ever felt unsafe. 


FWIW we fully disassembled this year, moved to a new home, and put it right back together. The joinery worked out perfectly.

Be aware, maple is stronger and stiffer than poplar; more expensive though.


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## percent20 (Feb 8, 2019)

> +1 There are standard CPSC safety rules SAFETY STANDARD FOR ENTRAPMENT HAZARDS IN BUNK BEDS (CFR Title 16, Chapter II-B, part 1213) on commercial loft beds for height of railing above the mattress and opening between the rails. It is a good guideline to follow for DIY.
> 
> Not many wood movement issues with bed, following standard design shapes.
> 
> ...


All great information. I was planning on assembling the ends completely and the side rails then using some kind of bed breakdown hardware to secure them in. Still looking at all the options.



> I built a very solid bunk bed from maple. You may draw some inspiration on knock-down joinery, dimensions, etc from this project.
> I have 3 kids, and I ve been on the top bunk with the 3 of them and never ever felt unsafe.
> 
> 
> ...


Great build, it looks awesome.

It is interesting you did through mortise and tenons. I was actually thinking, this morning, about doing floating mortise and tenons except with some metal plate for extra strength. Then do some wood pins through the tenons on each side.

Any thoughts on something like that?


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## JohnMcClure (Aug 24, 2016)

> It is interesting you did through mortise and tenons. I was actually thinking, this morning, about doing floating mortise and tenons except with some metal plate for extra strength. Then do some wood pins through the tenons on each side.


Seems reasonable. I think the stronger, harder, stiffer metal piece might concentrate stress on the end of the rail, though. Thru tenons would be my recommendation for that reason, but you could go full width if you're worried about strength. Easier that way too. Just gotta make sure the post is thick enough to handle such a large mortise… 
Strength density is why I went with maple btw.


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