I’ve been reading on Reddit (r/mattressmod) and am seeing a few mentions of individually pocketed coil sets shrinking over time, losing a few inches in both length and width. As a result, the latex or foam topper begins to overhang the support layer, and the coils start to deteriorate. I’m wondering if this is a widespread issue or a rarity? Is it only a problem with adjustable foundations, or in general? Are there things that a DIY’er needs to keep in mind when building a mattress to prevent this from happening? Do the manufacturers and retailers cover shrinkage in the warranty? Thanks.
A pocket coil unit should absolutely not shrink over time. Like everything not all pocket coil units are equal. Unfortunately there are some players who make units that out of cheaper raw materials and to cut costs will use less wire and stretch a coil to achieve the height.
You wouldn’t believe some of the pocket coils that we see in mattresses these days. (in ones that are supposed to be good quality)
Its difficult to offer a warranty on a pocketed coil for DIY not knowing how it was treated or used. For us, we really only sell the DIY space to help out DIY builders. We aren’t really set up for single unit sales but we manage. Our units should outlast everything else in the mattress based on normal usage of a mattress.
My advice is always to keep the build simple. If you are using a pocketed coil, then build your mattress in way that allows the pocketed coils to do their job. You don’t want to over build and have too many layers above the coils.
Also recommend a good fitting cover to keep everything aligned.
Don’t go down the “advice” rabbit hole either. There are basic guidelines but a mattress feel is personal. Your body and your sleeping style all play a part.
There are a lot of good mattress folks on here that I’m sue will have some good advice as well.
Great question.
As PCS mentioned, coil shrinkage shouldn’t happen, but from our experience we’ve seen it occur from time to time. We call it the “accordion effect.”
We noticed this more often years ago when we used an older coil supplier whose units didn’t have enough structure. The main issue, especially for DIY builds, is that the coils and comfort layers are in the same compartment. When everything is loose like that, it allows movement and compression over time, which can lead to that accordion effect.
We ran into this same issue ourselves until we made a couple of big changes. First, we switched to a much better coil system that had stronger side structure. Second, we redesigned the mattress so the coils and comfort layers are now in separate compartments. We also hog ring the coil unit to the inside cover, which gives the mattress even more stability.
Since making those updates, we’ve only seen the shrinkage issue a handful of times, and that’s usually when a mattress has been roll packed.
There’s a reason most mattresses are either tufted or glued together. It keeps all the layers locked in place and prevents shifting. Unfortunately, with a lot of DIY builds, you’re more likely to see not just the coils pull in a bit, but also the latex shifting around because the components aren’t anchored.
We actually shot a video about this exact issue if you’d like to see it in action. You can check it out at the link below.
Hope this helps!
