25 or 28 ILD zoned or solid topper over firm latex Ikea Edsele

[phoenix]

Hi bixentin,

Thanks for your reply Phoenix. The Mountaintop Foam C3 firmness is rated an equivalence of about 21.5-24.5 ILD, so as you said it’s hard to judge the equivalence of that to other latex formulations as my experience is certainly that it feels firm rather than medium. On the other hand the 20% natural latex layer on the Holmsta was very soft so I feel it must have been a lower rating than the C3.

With other types of latex an ILD of 21.5 - 24.5 would be in the soft or medium soft range and I think that most people would agree that the Ikea latex feels firmer than that. ILD is also not the only spec that affects how soft or firm a latex layer will feel so by itself it can sometimes be misleading (see post #4 here). Synthetic latex has a lower compression modulus (the rate that a material gets firmer as you compress it more deeply) so with latex that has a higher synthetic latex content … even if it had the same 25% ILD it would feel softer to many people.

Neal at Spindle sells the Mountaintop latex and is familiar with the feel of other types of latex as well and would probably be the best source of guidance about how the Mountaintop ILD’s relate to other types of latex.

I found the Ikea Edsele had an unpleasant off-gassing smell for about 6 weeks which makes me concerned about butadiene with young babies around. I know that the blends are supposed to be ok for VOCs but butadiene is apparently toxic in such tiny amounts that I’d probably have peace of mind with a thin layer of natural latex on top of a blend.

The butadiene in synthetic latex is styrene butadiene so just like the chlorine in salt (sodium chloride) it can be more harmful when it’s by itself but is less harmful when it’s chemically bound to another substance. You can also see the limit value for Butadiene in the Oeko-Tex testing criteria here and .002 mg/m3 is very low (and this is the upper limit of the test not the actual amount in any sample). This is about 1 ppb and is approaching the amount of butadiene in ambient air in urban or suburan air primarily from car exhaust (which averages about .3 ppb). There is also more information about butadiene exposure here. Having said all that … these types of numbers can still be confusing and difficult for most people to translate into terms that are meaningful in “real life” so I do understand your concern and the “better safe than sorry” approach.

I could afford a 3" natural but I only just realized that much of the natural rubber tree latex comes from plantations mostly from deforestation in SE Asia. My mother is a wheelchair bound old lady who spends her time as a fervent orangutan activist, so I have spent most of my life trying to avoid palm oil, non-FSC certified wood, and beef (S/America deforestation, but similar deal). Consequently I believe - contrary to the greenwashing on the internet - that a synthetic/blended latex from petrochemicals probably has less of an environmental impact than the demand for natural latex which fuels rapid deforestation, increasing CO2 levels and causing species extinction.

I also understand your concerns here. While most latex plantations in SE Asia are now fairly mature ecosystems that don’t contribute to deforestation or CO2 issues as much as they did when they were first planted … this can certainly be an issue in countries or areas where primary forests are being replaced by tree plantations (cocoa, coconut, rubber, oil palm). As you know these are all personal decisions that each person needs to make based on their own personal convictions.

Do you know of any suppliers that claim to use latex grown from trees that have been maintained in an existing diverse forestry environment, or any kind of sustainable forestry claim?

No I don’t … but if there was I think that it would most likely come from South American production where the rubber tree is a native species rather than SE Asia or Africa where they aren’t and the vast majority of natural rubber that is used in mattresses comes from SE Asia.

Phoenix