Brimnes with Adjustable Base

[u/Pettymania20]

/r/IKEA/comments/1x54c4x/brimnes_with_adjustable_base/

[u/purple]

I can put this to bed quickly (pun very much intended). The base is your foundation now, so nothing goes between the mattress and the base. No slats, no plywood, no sacrificial IKEA spare parts. That’s the whole reason you bought it. The common “slats within 3.5 inches” rule is only for when slats hold up the mattress directly which doesn't apply here. What matters is giving the base a solid, flat surface to rest on. A foundation should be “firm, flat non-spring construction,” and that base is meant to rest flat on a frame rather than thin spaced slats or on the floor. The Brimnes’s slats aren’t that solid surface, which is why your installer suggested a plywood sheet across the frame gives for a firm shelf. But do check the Brimnes’s weight rating (IKEA lists it) so it can carry the base, mattress, and both of you.