These 4" , or the traditional 7.5" thick foundations are made from cabinet grade,untreated spruce wood. The wood is covered with organic canvas, padded with organic cotton batting, then covered with 100% certified organic cotton fabric. These 4" foundations help put the mattress closer to the floor.This is good for babies going from the crib to a twin. The 7.5" foundations put you up higher.Wood foundations allows the mattress to breath easily, and also work the same way as a platform wood bed with slats.

The Organic Mattress Stores™ foundations come in 2 depths. 4", and 7.5". The 4" is designed for bunk beds, but can be used on any metal or wood bed frame.The 4" puts the bed lower to the ground.The 7.5" is standard. If you already have a platform bed,a futon frame, or a bunk bed you may not need a Foundation at all.Remember to measure from the bottom of your bed frame up the headboard, to see how much foundation you will need, without allowing a gap in the headboard for your pillows to go thru.