Hi, do you know where I can purchase a twin mattress in an 84" length? I want a two sided that can be flipped, latex mattress either firm or just under that rating, not sure without trying it? It will be for on an adjustable bed to replace my current latex/memory foam mattress. I’m near Lancaster, OH. The Original Mattress Factory in Lancaster can build one for me, but they only do custom latex mattresses with the polyfoam core. I wanted to stay away from using polyfoam as I have heard it isn’t very durable? Thanks for any help!
Hi Cat3,
Welcome to the Mattress Forum! 
Is your adjustable bed a split California King? Those are 36" x 84". A “normal” adjustable bed base would be a tine extra long, which would be 38" x 80".
Regardless, many latex manufacturers can do custom sizes for you, but you’d have to phone to see what they might have available for you and if they would offer it as a two-sided. A good place to start your search would be to look online and use the experience and expertise of the members listed in post #21 here who are all very experienced and knowledgeable and specialize in providing the type of help and guidance on the phone that can help you make good choices. There are a wide range of latex options included in the choices there and I believe that all of them compete well with the best in the industry in terms of their quality, value, service, and transparency.
If you’re considering making your own mattress, you can look at the different vendors in the component post here who offer both latex foam and covers.
Closer to Lancaster, here are two places that you may wish to visit to see if they are able to create an all-latex mattress to your specifications:
www.millersfurniture.com/mattress.html Plain city, Lancaster, OH. Retail store that carries a full range of Amish made mattresses made by Rainbow Bedding in Sugar Creek. They make innersprings, latex, latex hybrids and memory foam and use high quality materials and have good value. Well worth a visit.
https://www.designsleep.com/ Yellow Springs. Retailer that carries Berkeley Ergonomics which are a line of latex and latex/innerspring hybrids which are good quality and value. They are also very knowledgeable about mattress materials and construction and are great to deal with.
As for the difference between a polyfoam core versus a latex core, a latex support core is more durable, more resilient, more elastic, more adaptable to different weights and shapes and sleeping positions, more supportive (it has a higher compression modulus so it gets firmer faster with compression), more “natural”, and has a different more “springy” and responsive feel than polyfoam. It is a higher performance material. Of course it is also more expensive than a polyfoam core and for some people … a latex hybrid which has the benefits and “feel” of latex in the upper layers (the top 3" - 6" which are the most subject to wear and tear and contribute more to the overall “feel” of a mattress) is worth the cost tradeoff.
There is more good information about polyfoam cores and the densities to look for here.
I hope that information helps you on your search.
Phoenix
Buying a mattress too small is the biggest mistake.If you want to purchase a twin mattress, so the dimensions are approximately 38 inches wide by 75 inches long.In fact, two twin extra-long beds pushed together are about the same size. These mattresses are more comfortable than the other mattress. You can easily buy all the mattress online. It is the great platform to search anything you want and buy it.