I've always preferred a mattress with a firmer feel, but the Plank Firm pushes that preference to the limit. It's unyielding, with the bare minimum cushioning. Like all the best firm mattresses, it creates incredible support — but does that come at the expense of pressure relief? Here's what I can tell you after two weeks of sleeping on it...
Type: All-foam (flippable)
Materials: Support foam, comfort foam
Firmness (1-10): Firm (8) and extra firm (9)
Height: 9"
Trial period: 120 nights
Warranty: 10 years
Price (sale): From $524.30 at Plank Mattress
The Plank Firm Mattress is a dual-sided bed that offers a firm and an extra firm surface. To find the best mattress for every sleep style and body type, the Tom's Guide sleep team has to test a lot of beds. And that means trying mattresses outside our (quite literal) comfort zone.
My first impression of the Plank Firm Mattress was, "Am I lying on the bed frame instead?" After over a week, my opinion has completely changed. That initial firmness has given way to something that's still very firm — that will never shift — but also comfortably supportive.
You can read my Plank Firm Mattress review for a full breakdown on the bed, but with the Black Friday mattress deals offering 30% off this extra firm bed, I want to give you a run-down on why you should consider the Plank Firm...
What is the Plank Firm mattress?
The Plank Firm is a double-sided mattress: firm on one side, and extra firm on the other. You can read my first impressions of the bed with my Plank Firm Mattress hands-on review. I've now spent more than two weeks testing it, and my full review will be coming soon (so watch this space).
Before I dive into my experience with the Plank Firm, let's talk a bit about firmness rating. We measure mattress firmness on a scale from 1 (incredibly soft) to 10 (rock-hard). Most mattresses fall somewhere in the middle, with the majority of models tested by our team earning a firmness rating between 5 and 8.
I rate the Plank Firm as an 8 out of 10 on the firm side, and a 9 out of 10 on the extra firm side. It's the firmest mattress my team has tested, and it's been designed to mimic traditional Japanese floor mattresses.
The build is incredibly simple. At the core is a 6" layer of high-density support foam. This is primarily responsible for the feel of the mattress and provides the bulk of the support. On the firm side, this dense core is topped by two inches of comfort foam and finished with a quilted cover using track-and-jump stitching to add a tiny bit of plushness.
On the extra firm side, the only thing between you and the support foam is the cover. The basic quilted design leaves the surface almost entirely flat. Like all the best mattresses in a box, the Plank Firm comes rolled and vacuum-packed.
My experience sleeping on the Plank Firm
The Plank Firm is a double-sided mattress. I knew from my previous hands-on experience that the firm side was closer to my usual sleep references than the extra firm side.
So for testing, I decided to jump right in with the extra firm side. I figured if I hated the extra firm feel, I'd have the firm side to look forward to — but if I started with the firm side, I might never convince myself to switch to extra firm. I've now been sleeping on the extra firm side for more than two weeks. Here's how it's going...
Night 1: Unexpected firmness
Before the Plank, I wasn't unaccustomed to a firm bed. As a stomach sleeper, I prefer sturdy support at my hips. However, most of the firm mattresses I've tried haven't skimped on the cushioning, meaning while the support stays firm, there's still something soft yielding to your body.
There's none of that with the Plank Firm. The best mattresses for stomach sleepers tend to have some padding, but the Plank is flat and firm. It takes some effort to set up a mattress — my first night on the Plank Firm, I felt I might as well have left it and slept on top of the box it came in instead.
The all-foam build of the Plank Firm can be a little misleading. The best memory foam mattresses typically have cushioning and contouring, but the Plank Firm has an almost deadened effect. You don't sink into the surface, but it also lacks the bounce you might expect from the springs of the best hybrid mattresses.
This makes it an easy mattress to move around on. The freedom to toss and turn immediately appealed to me. Even though there isn't any bounce, I don't have to fight with the bed every time I want to shift my knees.
Night 2-7: Exceptional support, no cushioning
During my first week of testing the Plank Firm, my major complaint was a lack of 'coziness'. When first climbing into bed, I would have appreciated a little welcoming cushioning, to deliver that 'ahhh' effect.
Once I'd settled into the mattress for the night, however, the major benefit of the Plank Firm became clear: the support. The Plank Firm is endorsed by the American Chiropractic Association for back pain relief, and Plank describes its bed as offering 'perfect spinal alignment.' It's hard for me to disagree with this, as the total lack of sink means my spine is forced to remain straight while I sleep.
Even when I was still breaking in the bed, I could appreciate the support from my shoulders to my toes. I don't experience much backache, but after lugging my heavy bag to the office, I get some twinges in my lower back. The Plank Firm could rival the best mattresses for back pain for how it continually supports my lumbar region.
That support can be felt in every corner of the bed. The edge support is strong, and even sleeping right up against the side there's no sink. I was even taken by surprise a few times when I'd unthinkingly sit on the side because the total lack of give is like sitting on a chair.
At this point, the firmness was still requiring some adjustment. Sometimes I'd try to snuggle into the bed, only to be greeted by a surface that hardly yielded. As someone used to a plush hybrid, it was a little disorientating.
Night 8+: Support still shines, some cushioning?
Having spent more than a week sleeping on the Plank Firm, I've gradually grown into the firmness. And to my surprise, I've started to notice some cushioning. (Yes, really!) This is never going to be a plush mattress, but there's enough subtle cushioning to ensure I never feel I'm lying on the floor.
That touch of comfort helps me really appreciate the support of the Plank Firm — especially at the hips. I'm used to firm mattresses resulting in a bit of pressure at the hip bone, but that's not a problem with the Plank Firm, even with that extra firm rating.
Admittedly, there are still times when that hard surface is just too much, Primarily, if I'm going to bed with a full stomach. With almost no pressure relief across the belly, the Plank Firm can feel like wearing a tight pair of jeans. In the future, if I know I'll be eating late, I'll consider flipping the mattress (remember, it's a double-sided design).
The more pressing issue with the Plank Firm — and pressing is the operative word — is for side sleepers. Without soft or responsive upper layers there's almost no relief where your shoulder presses against the mattress. I can identify if I've rolled on my side during the night on the Plank Firm by how numb my arm is in the morning.
It's also worth noting that I sleep alone, so my mattress has to suit me and no one else. The Plank Firm does have some benefits for couples (the motion isolation is incredible), but the rock-hard feel isn't for everyone. The Plank Firm is for people who know exactly what they want from their bed.
Why I recommend buying the Plank Firm this Black Friday
The Plank Firm is like almost nothing else on the mattress market. If you're after a mega-firm dual-sided mattress that will still provide some pressure relief, you won't get anything better than this. For the Black Friday sales, Plank Mattress is offering 30% off the Plank Firm. Here are the current sale prices:
- Twin sale price: $524.30
- Twin XL sale price: $594.30
- Full / short full sale price: $699.30
- Queen / short queen / Olympic queen sale price: $932.40
- King / Cal king / short king sale price: $1,072.40
- RV king (72"x80", 70"x74", 70"x80") sale price: $1,072.40
These match the best prices I've spotted all year for the Plank Firm. I'm used to seeing 25% off, and this 30% off sale only comes around for big occasions such as Black Friday, Memorial Day, and Presidents' Day.
I expect this trend to continue moving forward, which means right now is the best price you're going to get on the Plank — with a possible extension into Cyber Monday mattress sales. Even in the standard sale, this is a mid-range model with a competitive price for a specialist build.
The Plank Firm comes with 120 nights to trial it at home plus a 10-year warranty. If you need extra cooling, upgrade to a GlacioTex cover for both sides at an additional cost.
