How to Make a Sleeper Sofa More Comfortable

1. Replace the mattress — pull-outs only, and it is transformative

Factory pull-out mattresses are two to four inches thick, because the mattress has to fold into the sofa cavity. That is why you feel the support deck and its crossbar.

A 4.5-inch gel memory foam replacement is about the thickest most fold-out frames will close on, weighs 44 pounds, and is the single largest improvement available in this category. It folds into a standard fold-out frame and it is CertiPUR-US certified.

Get the size right. A sofa-bed queen is 52 by 73 inches, not the 60 by 80 of a bedroom queen. Measure the mattress currently in the sofa, then measure the cavity with the sofa closed — that second number is the real ceiling and it is usually half an inch less than the old mattress. Full table in sleeper sofa mattress sizes.

2. A firm topper, not a soft one

This is the main fix available to a split-back, and the direction of the advice is the opposite of what people assume.

A soft topper conforms to the surface underneath, which means it finds the fold seam and transmits it. A firm topper spans it. Two to three inches of firm foam bridges a seam much better than four inches of soft memory foam, which is counterintuitive enough that most people buy the wrong one.

On a pull-out, a topper is second best to replacing the mattress and it does help, for the same reason: it puts distance between you and the deck.

3. Sleep across the seam, not along it

Free, and it works on the wider split-backs. The seam runs along the sofa’s length, so lying along the sofa puts the seam under your spine for its whole length. Lying across it puts the seam under one part of you.

Only possible where the surface is wide enough — the OSP Sawyer Convertible Futon Sofa opens to 66 by 38.75 inches, and the Liberty sectional to 88 by 66, which is genuinely usable crossways. On a 66-by-37.6-inch Serta Rane it is not an option.

Related: on a split-back, the seat you sit on daily is the surface you sleep on. Sitting in a different spot each evening spreads the compression, which delays the dip by a surprising amount.

4. Fix the support, not the surface

On a pull-out, check the support legs at the foot are dropping fully and bearing on the floor. On carpet they hang up, and a bed with undropped legs sags in the middle in a way that feels like a mattress problem.

On a futon frame, slat gaps let a thin mattress sag between them. A bunkie board or a sheet of thin plywood cut to the frame closes the gaps and is the cheapest real improvement available on that format.

On a split-back, there is no support to fix — the sofa frame carries the whole area, which is why capacities of 600 pounds are normal.

5. Bedding, which matters more than it should

Nothing is made in the sizes convertible sofas open to, so the practical answer is a flat sheet tucked or a duvet folded in half. A fitted full sheet on a 38.2-inch-wide surface pulls at the corners and comes off at 3am, which guests do not mention and do remember.

On a sofa-bed queen at 52 by 73 inches, queen sheets are loose but usable, and there is no mattress protector in that size in general retail — a flat waterproof pad under the sheet is the workaround.

A single decent pillow does more for a guest’s night than any topper. Sofa beds are low, so a thin pillow leaves the neck unsupported.

What does not work, so you do not spend money on it

A soft memory foam topper on a split-back. Sinks into the seam. This is the most commonly recommended fix and it is the wrong one.

A mattress pad. Half an inch of quilting does nothing about a structural join or a steel bar.

Turning or rotating a convertible’s cushions. On most split-backs the seat is fixed, and where it is not, both sides have the same seam.

Adding plywood under the mattress of a fold-out. It stops the mattress folding, and the sofa will not close.