Building a wood bed platform - how much will it support?

  • Thread starter kwijbo
  • Start date
Because of size constraints in my room, I need a platform for my queen size bed that is the exact footprint of the bed (60" x 80"). I've decided to attempt to build it however I have no experience with this and hopefully someone can point out any flaws in my plans.

I've attached an image showing how I'd like this to work. The colored items are as follows:

Red - 2x4 60" in length. 2 pcs
Blue - 2x4 77" in length. 3 pcs
Green - 6x6 10" in length. 4 pcs
Not shown - 1x3 60" in length. 12 pcs (slats)

The plan is as follows - make a rectangle out of the red and blue pieces with the 1.5" side of the 2x4's parallel with the floor for maximum load bearing capacity. The blue pieces will be anchored to the red with 2 screws on each end, so a total of 12 screws will hold this rectangle together.

Then, the 6x6 posts will be put inside each corner and will be anchored by 6 screws per side or 12 per post. The tops of the posts will be even with the top of the 2x4s. Once this is done the 1x3 pieces will be laid across the top with about 3" of space between them to support the mattress.

If all that makes sense, my questions are:
  • Will this be enough to support me, my gf and mattress? 280 lbs for the 2 of us plus another 100 or so for the mattress (and some occassional, ahem, wrestling)?
  • Will support be needed in the middle?
  • Will the screw points be enough? What size screw should be used?
  • What are the chances of this loosening up over time?



Homework Helper
Here is what I'd do:

1. Use 2x6's instead of 2x4's for the blue and red rails. They are nearly 4x stronger in bending. Alternative would be 1x6's (2x stronger than 2x4's).

2. Make sure the long dimension of the rail is vertical. Looks that way from your drawing

3. Use carraige bolts instead of screws (all the way through the 6x6's). Bolts should be 3/8" diameter at least. Vertical placement of the bolts is a little tricky since you don't want the bolts at right angles to interfere with each other in the vertical direction (screws have the same issue).

4. If you can, notch the 6x6's so the edge of each rail rests on a ledge. Should work fine w/o the notches if that's too difficult.

5. Attach the middle blue rail to the red rails via joist hangers. Screws into end grain don't hold real well.

6. Use a 6x6 in the center if you can. May not be necessary if you use 2x6 rails.

7. The blue rails should be 3/4" lower than the red ones (to accommodate the slats)

8. You might consider 1/2" plywood (or even 3/8") instead of the slats. If the plywood is screwed to all the rails and the 6x6's you'll have a rock solid frame. Also, no need for vertical offset between the blue and red rails since the plywood would cover everything.
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I did something similar. I built a bed frame for a California King mattress, and it has worked out great.
I have 4x4's for the legs, and I have 3 down each side, with a center one at the head and the foot of the bed, for a total of 8.

These are notched in the width(narrow end) of a 2x6, and down about 4 inches, so the rails will rest on the legs. I used regular bolts(Not carriage bolts), so that I can actually have a wrench or socket on each end, and I used washers so the head of the bolt and the nut wouldn't sink into the wood. They are 6" long 1/2 bolts, if I remember right.For the mattress supports, I have them going the short distance(I used 2x4's), not long, and I set them to be the exact height of the top of the 4x4 legs. I think I have 4 going across, hung by joist hangers. The 3 pieces of wood I have as a platform rest on the 4 small areas in the corners, plus the 4 legs spaces on the sides, as well as the cross members.

A little over-engineered, but it holds myself, my wife, both my stepsons(Teenagers), and my 2 years old daughter without even thinking about sagging. Probably 600-625 pounds or so. Nicest part is when I move, I undo 4 bolts, and lift out the 2x4's in the joist hangers and I'm good to go. I also have it at the perfect height for those big gray storage tubs you get at Wally World, so I have extra storage space.

I plan on sometime soon re-designing this and paying to have the wood cut and drilled more precisely than was previously done, I can get some pics that I plan to have our CAD people turn into plans if you are interested.
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Gold Member
Mine is different.
Blue rails are 2 x 6.
Reds are 2x3
Also 2 sets of 2x3 running from each blue outer rail .
A 2x6 running flat underneath the inner 2x3 for support.
Posts are 1 x 8 put in an L fashion - This is screwed into an outer blue and and outer red at each corner with no interference.
The red rails are lower than the blue to accomidate the 3/8 inch presswood surface. The blue rails are slotted so the presswood does not move sideways.
The 3/8 presswood is in 3 sections and attached to each 2x3.
Very stable.
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Science Advisor
Homework Helper
kwijbo: I currently assumed two thirds of your total load is sometimes applied to one beam (P = 1130 N). Hence, the 1956 mm long (blue) beams, using 38 x 89 mm southern pine lumber, grade 2, are slightly overstressed. The stress level is 106.5 %, which exceeds 100 %. (The allowable bending stress for the above 38 x 89 mm lumber is Sb = 10.34 MPa.)

This indicates 38 x 140 mm lumber would be needed for the three blue beams. (The allowable bending stress for 38 x 140 mm southern pine lumber, grade 2, is Sb = 8.58 MPa.)

It appears 38 x 89 mm lumber is adequate for the short (red) beams; their stress level is 83.0 %, which does not exceed 100 %.

I did not check your screws, but your plan sounds fine, except probably use a joist hanger for the middle blue beam, as mentioned earlier by others.
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There is a whole world out there for woodworking, cabinet making, may be worth paying a few bucks and buy a set of plans with instructions and everything on how to make a bed...of course, you would still have to modify a bit for your needs, but it would give you a nice idea, since you seem to be a novice at this.
Thanks for all the great replies - very helpful! General consensus seems to be 2x6's (Thanks nvn for the calculation!) so that has been changed in my plans, along with joist hangers. I'm also going to increase the height of the 6x6's 2" so that there is 6" of space under each side so I can slide under bed storage containers under it.

I would love to notch the 6x6's and the side rails but I don't have any cutting equipment, all cuts will be done by Home Depot and I don't think they'd be willing to do that (nor would I trust them).

I'm going to get the materials tonight and will hopefully post the finished product tomorrow morning. Wish me luck!


Science Advisor
Homework Helper
kwijbo: Do you mean you will use 38 x 140 mm lumber for the red beams, also? That would be great, in case you or I slightly underestimated the applied load.
... I would love to notch the 6x6's and the side rails but I don't have any cutting equipment, all cuts will be done by Home Depot and I don't think they'd be willing to do that (nor would I trust them). ...
A simple, inexpensive cross-cut hand saw can make those cuts easily. (A " Saws/saws.htm#backsaw"" is preferred, but not absolutely necessary.)
Here is a good how-to for simple joints:
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Science Advisor
Homework Helper
kwijbo: In stores such as Home Depot (i.e., not a professional lumber yard), I think lumber is often unmarked (not grade-stamped), in which case it might be grade 3, or anyone's guess. What is the species and grade stamp on the lumber you will purchase, because it makes a big difference in the allowable stress?
Your frame boards aren't going to be the biggest issue here. They will matter, but your weight is distributed over the entire surface that the bed meets with the frame, if slightly more down the long-ways axis. You should be more concerned about GOOD solid corners and a solid platform to rest the bed on. Do you have a box spring and mattress or just mattress?

Consider putting a triangle block in the corners and bolting each frame rail to that. Screws are a little sketchy for this application, if you ask me. At least as far as the corners are concerned. I like the idea of the plywood, but I would go thinner on the ply and just do some horizontal supports between the two long rails.
... Consider putting a triangle block in the corners and bolting each frame rail to that. Screws are a little sketchy for this application, if you ask me. At least as far as the corners are concerned. I like the idea of the plywood, but I would go thinner on the ply and just do some horizontal supports between the two long rails.
While planning my own bed frame project, I've been looking at some components sold by Rockler, Woodcraft, and some others. They have some nice steel bed-rail brackets, special "bed bolts", box spring support brackets, etc., in a range of prices. I generally like to fabricate my own stuff, but sometimes it just makes more sense (cost/time) to buy the pre-engineered pieces.
I agree. Sometimes is it just cheaper, easier, better, and safer to go prefabricated.


Staff Emeritus
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Is there any reason you can't just buy a metal frame? They don't extend past the bed, and you can be sure they're designed to hold it properly. They don't cost more than $150, I don't think. Maybe less...
Sorry for the late reply, I was out of town for a bit at a wedding. Thanks for the other replies too, the ideas are appreciated. I thought about a metal boxspring but I don't use a boxspring and it seems that most of the metal frames are designed for one. Prefabricated was a thought but I didn't quite find exactly what I wanted.

I did go through with everything and it came out pretty good, just a few niggles here and there but largely the final product is as expected. Here's how it went, its a bit long but hopefully someone may find this helpful in the future.

That Friday night I went to HD and spent 30 minutes looking at all the pieces I needed and after I felt confident enough about it I had them cut. The guys were really helpful too, which was nice. Also, for nvn, I believe all the wood was marked as Grade 2 on the pricing signs. I came home with

  • 3 77" pieces of 2x6
  • 2 60" pieces of 2x6
  • 4 60" pieces of 1x4
  • 4 12" pieces of 4x4
  • 3 primer spray cans and 3 black spray cans
  • 2 joist hangers
  • 50 #12 3" screws
  • 25 #6 1.5" screws

I painted everything first with rattle cans, primer and then black. It took about 5 hrs to paint everything and let it dry and the amount of paint was perfect.

I then had 2 friends come over and help me with the assembly. We attached the posts to the 2 77" outer pieces first, tacking each piece and leveling. As we were putting them together it appeared that the 12" posts weren't sitting level on the floor. It ended up being a combination of an unlevel floor and the 2x6's were slightly warped. Figuring we could just shim everything at the end we moved on. 6 screws went into each side and the posts felt held in really well. For anyone who may do this in the future, DRILL PILOT HOLES!!

We then tacked the 60" pieces onto the ends with 1 screw each so we could put in the joist. That went in without a hitch so next was leveling the ends before putting in the rest of the screws. At this point we figured we could still pull on the legs and get it a bit more square now that things were tacked on so my 2 friends pulled and twisted until the posts leveled up and then held them there while I drove in the screws. A bit imprecise but without a jig or something this was the best we could do.

After that it was very simple, a total of 12 screws went into each corner and then the slats were laid across the top with 5" of space between each, then they were tacked down with a screw in each corner.

I was a bit nervous about the screws being 3" long but they seem to hold well. Its been less than 2 weeks so if it was already loose I'd have made some major mistakes, but 6-12 months from now should be the true test. Everything cost almost exactly $150, so it wasn't as cheap as I was thinking it would be but still cheaper than most premade platform beds. The cost was also inflated a bit by the 1x4's used for the slats - they're kind of finished? and cost $65 for all of them, I think it might be decking boards.

All in all, I'm happy with how it came out. Its not 100% perfect but given what I was working with I can't complain. It gives me under bed space, fits my dimensions and it was fun to build. A pic is attached, comments and questions are welcome. And of course thanks for everyone's help!



Science Advisor
Homework Helper
kwijbo: Very nice work. I too am slightly nervous about the screw lengths. If you change your mind about the 76-mm-long screws, and the slat screws, I think you could carefully remove one 76 mm screw at a time, drill a slightly deeper (very small) pilot hole, then carefully install, e.g., a 102-mm-long screw (and a 64-mm-long slat screw).

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