Would like opinion on the following mattress construction

I have looked at some mattresses within Tempurpedic line and liked Rhapsody. I was planning on ordering a third-party version - through one of retailers recommended here - but ended up needing a shorter mattress - ideally 8".

I am 200 lbs and tend to like firmer mattresses. I sleep on back/stomach. My wife is side sleeper.

Now my plan is to get one from Rocky Mountain. The current thought is the following construction
Venus 8lb 1in
Sensus 5lb 2in (alternatively Aerus)
ILD 35 2in
ILD 40 3in

That makes it total of 8in.

I am flexible in terms of foam used - can use more/less of Venus/Sensus/Aerus.

I would appreciate your opinion on this construction.

Hi aoysgelt,

Your construction looks to me like it would be appropriate for you and your design goals “in theory” and for most would also be on the firm side that you are looking for (both because of the use of higher density foams, the thinner 3" comfort layer, and because the support layers are on the firmer side as well. It may be a little on the firm side for your wife though (depending on her body type, any variations in her side sleeping, and sensitivities as well)

Of course firmness and softness is very subjective and with memory foam can also be somewhat variable depending on the sleeping environment, the specific qualities and response of the memory foam itself, and which of these qualities or responses different people are more sensitive to and relate more to their perception of firmness. For example a certain foam that is more sensitive to body temperature and takes longer to warm up may feel firmer to one person who moves a lot than it will to another who doesn’t move a lot while they sleep even if the foam itself is softer under the weight of the body once it is warmer. Specific body shape and type and sleeping position variations will also play a role beyond just weight itself and the “basic” sleeping position.

Overall though … to me this would seem to be a good choice of layering for your weight and design goal and if firmness was the goal I would also likely go with the Sensus. “In theory”, and for most people, it would also likely be firmer than the Rhapsody although “apples to apples” comparisons with different types of memory foam mattresses are difficult without more feedback from a larger group of people who have specifically compared the two different mattresses. I would also tend to run your thoughts by Rocky Mountain who have more direct experience with Venus/Sensus combinations and my have some additional input that would be valuable as well.


Thank you for your thoughts.

Any opinion on making Venus a thicker layer - e.g. 2in of Venus and 2in of Sensus with only 4in of support base 35/40?

Hi aoysgelt,

I would tend to be more conservative (meaning use thinner layers) with 8 lb memory foam because it is more “effective” at relieving pressure in thinner layers. This is because of the combination of its high density, low IFD (12 lb which is the same as the Aerus but lower than the Sensus) and higher sag factor (compression modulus).

There is a good series of videos here which talks about the different FXI memory foam that they offer.

I should also mention that Rocky Mountain Mattress also does custom builds and can make a mattress in any layering combination you wish and it may be worth talking to them to see if there would be any difference in price between ordering the layers separately and putting them together yourself or having them build it in the layering you wish (assuming that isn’t what you are already thinking). It would also be a good idea IMO to talk with them about the layering that may work best for both of you because they have a lot of experience in how various layering combinations will affect different people using the specific foams that you are considering and may have some suggestions that may be helpful.