Beds come in multiple sizes to suit children, teens, single adults and couples. They consist of a frame and mattress and, in some cases, a headboard and/or footboard. What you don't see is that the mattress is held up by slats, which ensure the mattress doesn't fall through the frame and to the ground. The size of slats should accommodate the weight and size needs of the bed.
Bed slats should be a minimum of 3/4 inches thick to provide enough support for the body weight on the bed. Anything less is likely to break under the weight of the body. If you need additional support, you can use wood up to 3 1/2 inches thick. Cut the wood to the width of the bed with a little extra on the edges, which you can trim down to fit securely on the inside of the frame.
Bed slat wood type doesn't need to be a specific variation. They can be made out of all types of sturdy wood including cherry, mahogany, oak or pine. Take both the type of wood the frame of your bed is made of and cost considerations into account when selecting the wood for bed slats. For example, pine is an inexpensive wood type but is also softer than cherry wood or oak.
You can either purchase wood that is already sanded or sand it down before you place it on the frame. Splinters can get stuck in your skin or your mattress and allow dirt, dust, debris or bugs to get in it. Since the wood isn't going to be exposed, it doesn't need to be stained or sealed, but you can add a finish if you want a uniform appearance on your bed. Don't place the slats in place until the finish is completely dry.
Place the slats evenly along the length of the frame. If you feel that the number of slats you're using for the bed is not enough, add more. If the slats aren't completely straight across and have any curves or bows, place the upper or high side facing up to give the bed the most support.
Specific Bed Slat Sizes
The different size of your mattress and bed frame requires your slats to be different lengths.
A twin bed, the smallest, measures 38 inches across. Leaving about 1/2 inch on each side of the slat to allow it to fit in the frame, as opposed to being on top of it, cut the slats to 37 inches. You may need to take them in an inch instead of 1/2 inch, which results in a 35- inch slat. A full size bed is 53 inches across, resulting in either 52 or 51-inch boards. For a queen bed, cut the slats to 58 or 59 inches, and for a king, the slats should be 74 or 75 inches.