Hi RemiRoo,
Post #2 here and the other posts it links to will be helpful. The choice of material in a topper is a personal preference but the quality of the material and its resistance to softening and breakdown no matter what it is will determine it’s durability. Latex is a durable material in all its forms (you can read a little more about the different types in post #6 here), the minimum density of memory foam I would consider is 4 lbs (and 5 lbs would be more durable), and the minimum density polyfoam I would consider is 1.8 lbs (2.0 lbs and higher would be more durable).
Sleepy’s carries a 2" and 3" Talalay latex topper which is a good quality material and may be well worth testing as a mattress/topper combination.
That would depend entirely on the quality of the “plush” material in the top layers of the mattress. In most cases plush mattresses that use lower quality materials would be a poor choice if the materials are lower quality (which is usually the case) which will soften and break down too quickly. If the plush materials are higher quality then you wouldn’t need a topper to go with them because the mattress itself would likely be soft enough without one. The trick is being able to find out the quality of the plush materials in the mattress. the soft low quality materials that are so often used in the upuper layers of mainstream mattresses are the biggest reason for premature softening and breakdown and if there are no options where you can confirm that the comfort layers are both soft enough and high enough quality then I would look for a mattress that minimized unknown or lower quality materials (which would be firm because the comfort layers would be thinner) and then add a higher quality topper.
While a topper will improve the durability of the upper layers of the mattress to some degree … this wouldn’t be a main factor in my decision because when the lower quality materials soften under the topper then the topper will just follow the dips and soft spots in the mattress. If you do go with the topper/mattress combination I would look for a firm mattress that used as little as possible lower quality materials and then choose the topper thickness that would give you the comfort/pressure relief you need.
The law tag only provides the percentage of materials based on weight and doesn’t give any indication of the quality of the materials or the thickness of all the layers. If you were able to provide the specific layering information and the density of the foam in each layer then it would be possible to know more specifically but in almost all cases it would be too much low quality softer polyfoam (the urethane foam) in the upper layers of the mattress. The polyester fiber batting is probably part of the problem as well (it compresses and forms impressions over time) and the fiber by-product could also play a role depending on what and where it was in the mattress. The spring is the support system and it’s probably still in good condition.
The law tag doesn’t really provide any meaningful information because it only specifies the type of material not the quality and all materials have good and poor quality versions. If you look at the example of a mattress design here (from Sleepy’s website) then you will see an example of the actual layering of a mattress from their spec sheet. This doesn’t show the quality of the layers either (which are in lbs/sq ft for polyfoam and memory foam) but it does show the thickness, type, and order of the layers and when you see words like hypersoft, super soft, convoluted supersoft, supersoft activeflex, or activeflex then these are just words for different types of polyfoam and unless they also show the density then it would be safest to assume it’s low quality. In this case there is a total of 5.5" of polyfoam in the upper layers of the mattress (with different names) and I would avoid any more than 2" in the upper layers if possible (and even this is more than is ideal) unless you know it’s good quality (at least 1.8 lbs density or higher for polyfoam or 4 lb density or higher for memory foam).
Phoenix