Replies

1. 
   rholland54 | Jul 28, 2003 08:53pm | #1

   Are you using a mattress without a boxspring ? if so I would use 3/4" plywood to support the mattress.  You will need to support the plywood at the midspan, as it will not support the weight spanning the full width of the bed.  When you say platform bed do you mean an enclosed base like a box, in which case your center support for the plywood base can bear on the floor.  I built a double size platform bed with built-in drawers.  Customer used only a mattress,  which was on 3/4" birch plywood.  In my construction the plywood was supported  in center by the drawer case construction.

                                         Robert

1. 
   Shalom | Jul 29, 2003 06:45am | #2

   Thanks for you quick reply Rholland54. Perhaps "platform bed" is a misnomer. I built a frame bed and hope to support the foam mattress on the frame. My intention was to hang slats across the bed from a one inch ledge running along each rail. These slats would be around 61 inches long. I would then put a flat sheet, perhaps 3/4 inch plywood on the slats and my mattress on top of that. My fear is that the plywood would bow. Placing a support under the bed that would go to the floor, as I think you suggest, would wreck my design. Would 3 inch wide 3/4 inch poplar slats be strong enough? Or is my idea flawd from the start? Shalom

1. 
   JohnWW | Jul 29, 2003 07:59pm | #5

   Shalom,

   Use 2x6 Douglas fir, ordinary construction lumber, for the slats, it won't bow and it is inexpensive.  Spruce, hemlock, poplar, or tight grained pine would work as well if that is what is available locally.  The critical item is the thickness, a board that is twice as thick will be four times stiffer.

   If you're using construction lumber, spend some time picking through the stack of 2x's to get straight grained stock with small knots.  Buy a few extras in case a couple of them twist as they dry out.  Use kiln dried if possible and let it fully dry out in your shop for a couple of weeks before you joint and thickness plane it.  The pieces will probably end up around 1 1/4 thick. 

   If you want to lower the mattress a little, you can notch the ends of the slats where they rest on the ledges, this won't cause any loss of strength.  Space the slats a couple of inches apart and screw them to the ledge to prevent shifting and creaking.  I'd put two screws in each end of the slat.  Ordinary dry wall screws will work fine.  Drill clearance holes for the screws in the slats before you assemble the bed.  The spaces between the slats will allow the mattress to air out.  Mattresses on solid platforms can have problems with mildew forming on the bottom face.

   Hope this helps,

   John W.

2. 
   Wateren | Jul 29, 2003 07:41am | #3

   Shalom:

   I have built several beds of this type, but very utilitarian (ugly). My opinion, having used both, is that 1x3 is too narrow, 1x6 is much better. Although it maybe shouldn't matter theoretically, the narrower strips do not support each other as well. For a queen size I have always had one or two support rails lengthwise to support the weight, and recommend this.

   Last time I made one, I decided too late that plywood would have been better. I agree with Robert, 3/4" plywood gets the nod here. If you want it to look nice you can get nice plywood, I would use the cheapest construction grade myself. I recommend against MDF partly because it is heavier than granite and partly because I think it will sag with time. I might be wrong, no experience and lots of people have made lots of things with MDF.

   Okay, reading through your second post you don't want to put the lengthwise rail. I think the 1x and MDF are definitely out. Since you don't mind the thickness, what about two layers of 3/4" plywood? I haven't tried this for the 5-foot span but it sounds strong. Actually, you could use kiln-dried 2x10 instead, that should be good.

   Hope this helps somehow. Good luck.

   Cheers, Chris.

3. 
   Kell | Jul 29, 2003 03:22pm | #4

   shalom

   My opinion is that there is no way the poplar will support the weight of the mattress and two people.  I, too, recommend the 3/4 plywood.  If I were building this, I'd put some kind of mid-span support for it as well.  Without it, even the 3/4 ply will sag over time.

   Kell