I would get something firm with a pillow top and not a hard edge. They have some that if you sit on the edge, it will remain firm- it's a special feature so if you could avoid that it would help minimize the mattress look.

I know what you mean about "edge of mattress" feeling. I don't know how to avoid it, though.

In my area we have a company called Gardner Mattress Company that makes standard and custom sized mattresses. In your shoes, I would call them or stop by a showroom to find someone knowledgable and get their advice on what options they suggest to build a mattress that serves both functions well. Maybe you have something similar in your area? Maybe you need to head up to Boston to give away a free consult to a loyal GW member? (I'm kidding, sort of, but if you were bored ...)

I think the best way to avoid that is to go with a firm mattress and then do a foam topper on top of which you do a very tailored and batting filled zip cover. That will give you a deep firmness of cushion for the dining activity as well as enough plushness for relaxation or sleep. The back pillows will make the big difference here in comfort though. They've got to be firm enough to enable someone to sit forward enough on the mattress to serve as actual sit upright seating and not just curl up type casual comfort.

Pal - may I ask how wide is the banquette? I am assuming it twin size deep. Also what is a breakfast table?

Check if you have a Foam company in your area. I recently reupholstered a love seat and I replaced the foam inserts on the seat cushions. I found a store near my home (Southern Calif.) that has many choices and will custom cut the foam to the size and thickness you want. I wanted something very firm so I ordered the "Q41" (2.8 density, 41 firmness). Prior to inserting the foam into the fabric cover, I sprayed the foam with a special adhesive and wrapped it with 1" thick Dacron batting.

To get an online price quote and to learn about various foam types... open the A-1 link below, pick on the Foam link at the top. Next, pick on the square shape. Then, it will ask you to select
1. dimensions you want,
2. how the foam will be used,
3. select foam type.... just below #3 in small print, you will pick on "Click here to learn more about choosing the right foam for you". Here you will learn about various cushion/foam firmness and density and the numerical system used to rate a foam's firmness.
It will also have a chart for various foam types and typical uses including mattresses & breakfast nook applications.

I noticed that they can send you 10" x 10" samples. What you pay for the samples is applicable to any future order.
In my case, I was able to feel all the samples in the store.

-Laurie

Here is a link that might be useful: A-1 Foam and Fabrics

A breakfast table is an eating table that is smaller than a dining room table, and lower. A form of breakfast table is a Pembroke table, with a single drawer and two hinged leaves.

Mine is late Classical period, sits on a pedestal, has a false drawer and two hinged leaves. When houses were such that you ate breakfast in a morning room or in your bedroom, you would eat at this table, and since the chair was lower, I am assuming, so was the table.

The banquette will be 39x75 or 39x80, the same as a twin or XL twin mattress.

Why not just get a daybed, since that is what you are creating? Seems to be going to a ton of extra effort to try to call it a 'sofa'.

NB--no matter what you call it or how you trick it up, anything with a bottom cushion made up of a twin size mattress is not going to be comfortable to sit on as if it was a sofa, unless you are planning on designing huge deep back cushions. And if you are, you are back to a daybed frame :).

It's going to be built-in, and it will have fairly large back and arm cushions. It may actually slide under the back cushion support and be able to be pulled out for sleeping, I am not sure yet. And it also needs to be lower than a standard daybed, probably 16"-17" seat height.

Primarily it will be sat IN, meaning your legs and feet up in the sofa itself, but on occasion we may want to sit on the edge to eat at a table. We ate sitting on the edge of a bed for years when we had no kitchen so we got used to it.

Hmmmm. I think mattresses are so high these days. If it were me I would be tempted to get an organic cotton, possibly cotton and wool futon mattress from a place like this....

then maybe a wool waterproof mattress pad - those are heaven. and then whatever cover you plan on putting on it for sitting vs a sheet for sleeping.

Of course they have mattresses too, but they are not as thick as the kind I usually see.

Here is a link that might be useful: white lotus mattresses

I highly recommend the foam company I used for our swinging porch bed, as well as the place I ordered the cover. Linking below (feeding 1yo and can't look for the names):

Here is a link that might be useful: Swinging Porch Beds

I would use a firm or even extra firm mattress for when it's used daily as a banquette, and when guests sleep over I'd add a feather bed on top if it. Feather beds make any mattress so much more comfortable - it's like sleeping on a cloud. Of course you'd need space to store it as they are quite bulky but perhaps that could be built-in under the banquette. I have feather beds for the twin beds in one of my guest rooms used on top of the relatively inexpensive 6" firm foam mattresses. Have been told they are very comfortable and repeat visitors ask for that room.

Another choice is a 2" memory foam topper to be used on top of a firm mattress for more comfort at night.

Definitely get a 2-sided mattress so it can be turned for longer wear. Well worth the extra cost. Also I'd have a tightly woven custom cover made for it for daily use preferably that is washable.

He's napping so I can type now!

I ordered the DryFast foam for outdoors, but an indoor would be less expensive. The company I ordered from FoamFactory.com was VERY helpful over the phone. I did not take their advice and ordering/getting the cover first, since I special ordered it - I wasn't worried about being off so much the mattress would not fit.

It is wrapped in Dacron and very comfortable. On the phone, we went over where it would be used, how often, etc and he suggested what firmness to purchase.

The edges do not feel like mattress edges. And ordering online was less than the local places I called. Much less.

I'd get a true latex foam mattress or even just a piece of latex foam the desired thickness and have it upholstered. It is firm to sleep on, but gives enough to be soft and comfortable. It will never break down and the edge won't wear down from sitting on it. It also won't have that mattress edge feel.