Sofa Bed Mattresses Thickness Issues Are Not Obvious
This is a mechanical drawing of a sofa bed mechanism. It comes from probably the largest mechanism manufacturer of all.
What is significant about this drawing is that it shows the top of the closed mechanism at 13 inches from the floor. That's 13 inches minimum.
What is the height of the space allowed for the folded mattress? Only about 9".
The next illustration is the same drawing with the sofa bed (pink), and the mattress (yellow) added.
This is what a sofa bed looks like with the mattress folded within it. It works out to almost 14 inches high. Now suppose you you are typical height person. You measure a little less than 18 inches from the heel of your shoe to the underside of your thigh. So, how comfortable is it to sit on that sofa bed? Not bad. By the time the seat cushion compresses a little under your weight you should be pretty comfortable, because your feet will be resting on the floor.
If you check your regular couch, you will find a compressed height of between 15 and 16 inches. Now that's comfortable. Why? Because you can stick your feet out, cross your ankles and still have them resting on the floor. To do that with a sleeper sofa you would only have room to fit a 3 inch mattress. Three inches is just not enough to make a sofa bed comfortable to sleep on.
Sofa beds have been built to hold 5 inch mattresses. They sleep very comfortably, even with somewhat lower quality mattresses. Unfortunately, when you sit on them, that's another story. You feel like a little kid sitting in a grown-ups chair. Your feet dangle. That is no fun at all.
So manufacturers almost always make their sofa bed frames to fit a 4" mattresses.
Well how about stuffing a 4-1/2 inch or even a 5 inch mattress into this frame. Won't that be more comfortable to sleep on. The short answer, yes. The longer answer is, don't even think about it.
When you put a really good, quilted ticking on a 4" foam mattress core, it's already well over 4 inches. Add a little bedding and you are approaching the full mechanism height allowance. This mattress will completely fill the space inside the sofa bed. Suppose you put in a little thicker mattress. How much force do you think it takes to compress a high density foam, even a little. If it was easy to do, your body, at lets say 150 pounds would sink way, way in. Also the bar would sink in (upward from below). You can see that, assuming its a good quality foam, it would become very difficult to close the sleeper sofa, if you went even a little thicker than 4 inches.
But there is more. Suppose you have a mattress that is too thick. The 3 decks of the "mechanism" are hinged together. The hinge pins are strong steel rivets. Over time the rivets will wear pretty well, but the rivet holes will wear a lot faster. Fold this sofa mattress up many times a year, and your mattress will outlast the sofa ten times over. That's definitely not what we are after.
If you want a 4-1/2 inch mattress I will sell it to you, as long as you understand it will take two of you to close the sofa bed.
I will not sell a 5 inch mattress at all.
So if you want a price in a 4-1/2 in mattress, give us a call.