Confused with firmness

First of all, what a great forum! I have spent hours perusing this site. I am quite amazed at how much time Phoenix has dedicated to the site.

I am looking at buying one of brooklyn bedding’s latex mattresses off of amazon or the aerus from sam’s club. Our very expensive name brand coil mattress is starting to hurt after only 6 years. I don’t get the ILD difference between latex and memory foam. I know I like the rhapsody and cloud supreme offerings from tempurpedic. I have also noticed that what I think feels good when I lay down doesn’t necessarily feel good in the morning. To further complicate things, I am 280lbs and shrinking and my wife is 135lbs, pregnant, and growing! I am a side sleeper because of a spine injury and she is a back sleeper except when pregnant when she has to sleep on her side. She likes mattresses firmer than I do because she is a back sleeper.

So, I will probably be 80lbs lighter a 16 months from now and she’ll be back to normal and 115lbs again. (This is the 3rd kid, it’s just how she is)

I have been thinking I should just get two twins. A medium (higher ild) 3 inch comfort layer with a firm support layer for me and a softer comfort layer with medium-firm support layer for her. Does this sound right? Should I get something more firm for both of us and just use toppers until things get back to normal? I keep finding her on our soft foam couch at night because her hips hurt.

If I don’t go the latex route, would the 4lb foam in the Aerus get destroyed in the year it takes me to suck weight?

Hi Absentminded.

ILD (now called IFD but I still tend to use the old term) is simply a measure of how much weight it takes to to compress a foam layer 25% of it’s total thickness. It is measured slightly differently with different materials but it is a measure of relative softness/firmness of a material. With polyfoam it is measured using a 50 sq inch round compressor foot and a 4" thick layer of polyfoam which is 20" x 20". Wth latex the measurement is generally done on a full core which is 6" thick and is often measured in several places on the core.

With memory foam … ILD is really not relevant because it changes with the speed of the foot’s compression, temperature, humidity, and how long the foot is left compressed. Generally ILD in memory foam … as closely as it can be determined in anything approaching a standard way … is in the range of about 9 - 20 ILD which in other foams would be considered either soft or ultra soft (but of course memory foam can also feel very firm initially or with movement because it takes time to soften with heat, pressure, and humidity). There is a good article here on the pfa site about memory foam and IFD and how inaccurate and even misleading it can be with memory foam.

While there are many differences between latex and memory foam which makes them about as different as two different foams can be … the main one is that memory foam is a slow recover material and latex is a fast recovery material (with a few specially formulated exceptions). You can read about the pros and cons of memory foam here and the pros and cons of latex here but the choice between the two materials would be personal preference based on which type of “feel” you like the best. With your greater weight … then durability may also play a role and lattex is the more durable material. If you are looking at memory foam I would tend towards higher densities of 5 lbs or more because lower than this will soften much more more rapidly for you.

If you are considering a mattress from a manufacturer such as the Ultimate Dreams … then the people in the best position to give specific advice and recommendations would be the manufacturer themselves because they have a customer base with many different body types and sleeping styles and are more knowledgeable about the smaller details of their mattresses that may affect your choice besides just the latex itself. In particular Chuck is pretty good at helping his customers make good choices … particularly if you have done enough local testing to have a good sense of what you need and prefer.

Because of the large weight differential between you … it may be a good idea to consider a split “mattress” either with two twin XL sizes or with the type of side to side split layering that many of the online manufacturing members of the site (see post #21 here) offer to their customers.

There are some generic guidelines for different body types here and some for different sleeping positions here and more information about how different types of layering and construction here can affect these guidelines but this is a long term study beyond just scanning the information to get a general idea. There are so many variables involved in both different mattresses and in people that it’s usually best to talk with the manufacturer or outlet that makes or sells each mattress for more specific recommendations.

There is much more to every mattress than just the foam itself which can make a difference in the type of choice that may be best for you and it’s usually far more effective to talk with the “experts” that make or sell the mattress than to try to become the expert yourself and “design” a mattress based on "specs or what I call “theory at a distance”. The better outlets have years of experience which can help you make good choices either in person with local testing (which is generally less “risky”) or with an online purchase (which can be more risky but the risk can also be reduced with some local testing and giving them the type of information about your needs and preferences that can help them help you more effectively).