Hi Ari,
[quote]I think I have seen you say before that 1.8lb base foam is not great for the higher weight ranges? But in the post talking about the purecraft you seem ok with it. Can you elaborate? I’m confused
Almost all of these mem foam beds use 1.8 lb base foam[/quote]
I think that you’re confusing base polyfoam versus the comfort layers. I will provide a caution for higher BMIs and certain densities of foams, depending upon where those foams are located. This doesn’t mean that the foams would be inappropriate necessarily, but that there might be a tradeoff in durability.
With the upper comfort layers, I would recommend 2 lb for polyfoam versus 1.8 lb, but if 1.8 lb was used in the quilt I’d rather see it in the “inch or so” range.
I advise something similar for the polyfoam support core of a mattress for people of a higher BMI. 2.0 lb would be more durable than 1.8 lb, and 2.2 lb more durable yet (beyond this the density of HD polyfoam may not make much difference depending on how the density was achieved) and firmer would be more durable than softer (but probably require more foam above it), but none of these would likely be a weak link of the mattress depending on how much compression forces they were subject to and the thickness of the comfort layers. I explain this in a bit more detail in post #8 here, which was part of one of the links in the higher BMI link I provided earlier.
In the mattress you were considering from Pure Crafted Beds, this mattress uses a support polyform core of 2.4 or 2.5 lbs, which would be a high quality polyfoam, Beneath this is a base layer. Base layers are commonly 1" - 2", but this one is 3". Again, this is not the support core of the mattress, but a thinner base layer. The thinner base layer on the bottom of a mattress is evenly compressed rather than compressed more under the heavier areas of the body and less under the lighter parts of the body that have a larger surface area. The bottom layers will also compress less than the upper layers would if the same layers were on top of the mattress because the materials above them will absorb most of the compression forces and these forces also spread over a larger surface area as they travel through the mattress to the bottom layers. In this respect, I wouldn’t be as concerned with a bit of a lower density polyfoam base layer in the mattress you described.
Again, the recommendations I provide are meant as cautions to where you may experience slight shortcomings in durability over time for certain applications, but they aren’t necessarily meant to disqualify any particular item. I don’t recommend buying a mattress based purely on theoretical specs or what I call “theory at a distance” alone without doing some local testing first so you have a reference point for how all the different specs and combinations feel and perform for you. Different people (even of similar body types and sleeping styles) can perceive and interact with the same specs very differently. There are just too many variables in both body type (even at the same weight) and sleeping positions (there are many more combinations than just the three basic types) and personal preferences involved to be able to use specs alone to predict with certainty what any specific person will do best with.
Having said that … if you do choose to make a purchase based on “theory at a distance” … then I would go with the suggestions of the manufacturer or retailer you are working with. Each may have a different suggestion for you based on their knowledge of their specific designs and on their experience and feedback from their customers so you won’t find a “standard” set of suggestions between manufacturers based on specs alone. In general, they will use their knowledge of their mattresses along with the more detailed information that you provide on a phone call (about your specs, mattresses you have tested or are used to, and your preferences) to make a suggestion based on their best estimate about which of the mattresses they make or sell will likely suit you best. They will usually be fairly accurate for most people (most people do well with a range of specs or designs rather than an exact set of specs) but there is always the possibility that you are outside the “averages” they use so if for any reason their best suggestion doesn’t match what you need or prefer … then the ability to change the layering and/or their return or exchange policies can play an important role in your decision as well.
I hope that helps clarify things for you a bit.
Phoenix