Will this frame design be able to support a king mattress?

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Forum topic by ttrottier posted 07-28-2015 09:41 PM 1066 views 0 times favorited 17 replies Add to Favorites Watch
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7 posts in 1061 days

07-28-2015 09:41 PM

Hey guys I am new posting here but I figured it would be the best place to ask this.
I am building a floating bed frame for my king bed and before I move forward I want to make sure that the frame I have designed will be sufficient to hold the bed without flipping. tipping, or falling.
I have attached images of the frame from two views. The frame is edged in 1×6s, and the frame is to be made out of 2×3s. I have removed the platform covering on the bottom to reveal the leg supports. They will be 4×4s which will actually extend into the depth of the frame to make it more stable and easier to secure to the larger internal frame but I removed them here to make the design easier to see. Thank you so much for the help and I look forward to your answers!

Edit: The frame will be topped with a fabric covered OSB to provide full support to the mattresss. I removed it so the underlying work would be visible

17 replies so far

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Richard H

489 posts in 1708 days

#1 posted 07-28-2015 09:53 PM

I assume no box spring? My California king with box spring is supported by nothing but a frame along the outside plus one support member down the middle where the two box spring halves rest. If you are not doing a box spring you will likely need more support like what you have shown.

The only concern I have with your design is someone on the very edge of the bed tipping it over. I have a futon that has a mattress that overhangs about that much when it’s down and when I roll out of it it tips over. Granted it’s only a double mattress not a king but I would still be concerned. I think that’s why most bed designs have the legs all the way to the outside or just a few inches inside.

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7 posts in 1061 days

#2 posted 07-28-2015 10:04 PM

Thanks for the info it is a latex/ foam mattress that weighs about 90 lbs. The top frame will be covered with osb boards that the mattress will rest on, I left that out of the post by accident but I will edit that in. The design I am going for is something similar to this
It is a very popular form of bed so I cant imagine it being too unstable but I completely understand the concern as I am having it too, thus this post. The overhang on both sides is only about 10 inches So i am hoping that the weight of the mattress and all the wood will be enough to prevent it but I am finding myself skeptical.

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667 posts in 1250 days

#3 posted 07-28-2015 10:42 PM

A couple 3/4 questions
1. How are you fixing the 9/4X4 legs to the frame?
2. How long are the legs?
3. Are you shouldering them or just relying on carriage, through bolts or lags to hold them in place?
4. Aren’t you worried about frame sag at the perimeters?

-- I meant to do that!

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7 posts in 1061 days

#4 posted 07-28-2015 10:53 PM

1/3 the images don’t really explain it well, it will be shouldered and lag bolted to the frame
2. They are 12 inches tall but It feels like that may be a bit much.
4 Yes thats one of the main reasons I am asking here. I was just looking to bounce my thoughts off of the more experienced wood workers here too.

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667 posts in 1250 days

#5 posted 07-29-2015 12:03 AM

I’d simplify the frame pattern by removing close to 50% of the joints shown and move the edge of the legs to no more than 12” from the perimeter, (stability). I’d cut 3/4” shoulders on the legs, box them in and use carriage bolts as fasteners. I would half lap the 2X6 cross joints and run carriage bolts through the crosses to stiffen up the frame to legs connection. This would allow you to eliminate the 3 middle legs shown.

-- I meant to do that!

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7 posts in 1061 days

#6 posted 07-29-2015 01:55 AM

Thanks for the tips this is definitely along the lines of what I had in mind so i really appreciate your help figuring things out.

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5706 posts in 2841 days

#7 posted 07-29-2015 02:11 AM

It is certainly more complicated than it needs to be. I’m sure it would be plenty strong.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View RobS888's profile


2413 posts in 1873 days

#8 posted 07-29-2015 02:13 AM

You might want to think about something to constrain the foam mattress. It will move around slowly. It doesn’t sound like a big deal, but if the corner is exposed and you clip it at night you will not be a happy camper.

-- I always suspected many gun nuts were afraid of something, just never thought popcorn was on the list.

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7 posts in 1061 days

#9 posted 07-29-2015 02:28 AM

Pinto, I have since realized that haha. I was just really so worried about it not being strong enough.

Also Rob, The 1×6 has sits about 2 inches above the OSB to keep the mattress from moving. There is about half an inch of clearance on every side for sheets mattress pad etc. I am definitely worried about sharp edges though, I will have to round them or something.

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2768 posts in 2053 days

#10 posted 07-29-2015 07:14 AM

A way to make a 4X8 panel fit a mattress is to cut it diagonally. Butt the 2 diagonal edges together, and slide them relative to each other until you get the dimensions you need. Fasten the 2 pieces together with corrugated fasteners, or with joining plates. Cut off the protruding points that you no longer need.As long as the frame is adequate, this doesn’t have to be super strong. By the way, I’d prefer plywood over osb.

Only thing is, I haven’t tried this with a king size. May not give you the dimensions you need. But I know it works with a queen. You might have to play with how the diagonal line is cut. You can test it out with paper patterns cut to 4X8 inches, then try different diagonals til you get something that works.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View JoeinGa's profile


7736 posts in 2035 days

#11 posted 07-29-2015 02:07 PM

OMG … I built waterbed frames that held triple the weight with WAY LESS cross-supports than this.


So the quick and easy answer to your question is : Heck yeah! THAT’LL certainly hold the weight !

-- Perform A Random Act Of Kindness Today ... Pay It Forward

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1299 posts in 1758 days

#12 posted 07-29-2015 02:26 PM

I think you could park your vehicle on it without issue….... Jerry (in Tucson)

-- Jerry (in Tucson)

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7 posts in 1061 days

#13 posted 07-29-2015 02:34 PM

Runs with scissors that’s a really interesting idea. I think it might be tougher with a king. I think maybe I will cut the plywood into two twin sizes and anchor them with sheathing clips or something similar.

Jerry and Joe I think I have a fair amount of the complicated cross members and just go with an alternating 3 then 4 vertical joints. And I just checked to make sure and the farthest overhang is on the foot of the bed but it will end up being around 14 inches. I’m hoPing that it will be enough weight between all the wood and such. I am also thinking about putting plywood under the bottom legs too but I’m not sure if it would help at all

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27 posts in 1339 days

#14 posted 07-29-2015 02:53 PM

Another concern is when it comes time to move it. Can you dimantle it or does it sell with house?

-- a dull chisel is just a fancy screwdriver

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7 posts in 1061 days

#15 posted 07-29-2015 05:25 PM

I really haven’t thought of that yet. I am open to ideas though.

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