How much do 6 inch pocketed coils depress typically from the weight of say 5 inches of Dunlop latex weight on them.
Leggett & Pratt Quantum Edge Elite Bolsa. Haven’t done the build yet but (supplies ordered). Wondering if I should plan in a 1/2 inch boost somewhere if I really want to land at 11 inches of internals?
Or will compression of the springs by the latex only be only say 1/8 to 1/4inch.
Hi Fallguy007.
Of course, as you might guess the amount of the “depression of springs” depends on the Latex ILD on top of the coils. The higher the ILD (directly proportional with ILD in the case of latex) the higher the depression. One other factor is the surface area, the weight of the latex layer(s) is evenly distributed over the entire surface of the coil unit which would result in lower pressure per spring and minimal depression for a certain latex density. (e.g. 6" L&P Q Edge Elite Bolsa has 1041 coils in a Queen size and each spring will share the load)
Instead of putting my science hat on, I called Ken at Arizona Premium who sells the Quantum Edge Elite Bolsa to ask about the amount of spring depression under the weight of several latex layers. He said that when they place a 3" medium firmness (28 ILD) Talalay topper they get almost no visible depression of the spring unit. In his experience, even multiple layers of higher density latex will not depress the spring unit more than 1/2"(if that much).
Generally, all the layers of a mattress compress simultaneously not sequentially and they will each compress to different percentages of their thickness depending on their position on the mattress, the firmness of each layer, the compression modulus of the material, the thickness of each layer, and the compression force that they are exposed to (which depends on the weight of the part of the body in contact with the mattress and the surface area that is bearing that weight which is constantly changing as you sink into the mattress move or change sleep positions). Springs have a linear response to compression as opposed to latex that has a non-linear response to compression. Latex becomes firmer with compression increase and has the ability to allow for increased compression (allowing it to better conform to various body shapes and weights) as a result of the material’s open cell structure where each cell behaves like a micro-spring. Every layer of a mattress affects and is affected by every other layer in the mattress to different degrees. If you scroll down a bit more on this page you can read the Talalay Comfort Zone article by Ph.D. John Lean explains it in more detail, including this a picture of the linear spring response vs non-linear latex response with force applied.
Hope this helps with your decision
Phoenix