Sofa - Pull out bed - sagging? (sink, couch, compare)

[blakeas]

I have a sofa bed. the kind u pull out of the sofa. Well, really ever since we bought it (8 years) it seems like the ends are higher in the middle. I dont if it is sagging or the cushions just function differently when they are over the bed then the ends. How do I fix it? put a sheet of plywood down underneath the cushions so I have one uniform ledge all the way across?

[ShaneSA]

Flip the mattress. If it is still sagging in the middle, it is the support. add the board to it in the middle.

[blakeas]

its not the mattress that I am concerned about. it is when I sit on the cushions on the sofa. Seems like the ends are higher than in the middle - I just sink in the middle. Is there someway to correct that?

[ShaneSA]

That's a different issue. ooops. I guess I misunderstood. If it's the cushion sagging then it's the support in the middle of the suxhions. Look under the cushions and compare the support on the ends to the support in the middle. It may well take a board in the middle to hold the cushions even.

[blakeas]

do I just span the board over the ends of the frame of the couch? or does it just go over the actual pull out bed frame?