Sofa bed mattress is a sofa or sofa that has a pull-out bed built inside. This can be handy if you have limited space for a guest bed. For daily use, there is a sofa, but for guests, it becomes an overnight place to sleep. Eventually the mattress can be worn from folding, unfolding, and normal wear. If the sofa is still in good shape, you do not need to change the entire sofa bed, simply replace the mattress.
Remove sofa cushions to reveal bed frame and mattress. Fully fold the mattress and frame. Remove any blades or covers that may be present on the mattress. Inspect the underside of the mattress, especially at the corners to locate any bands or clamps that can hold the mattress to the frame structure. Tie or unlock these hold mechanisms. Pick up the end of the mattress furthest away from the sofa and lift it up, folding the mattress toward the top of the mattress when lifting. Lift up the folded up mattress and place it out of the way.
Place the new mattress on top of the frame. Make sure the bed mattress is facing in the right direction. If there are straps or clamps, these should be on the bottom of the mattress. Double check to see the mattress is properly positioned, as the mattress should not be bent or hang over the edges of the frame. Connect hold straps or buckles if the mattress has them. Raise the far end of the frame and fold it up over the middle section. Fold in the legs and fold again. Gently press the folded frame into the frame of the sofa and replace the pillows.