New Mattress Sagging FAQs | How To Fix Indentation | John Ryan

Mattresses are primarily based on a support unit which is then topped with comfort layers. It is when these comfort layers start to compress that beds suffer from dips and sags; known as mattress settlement. In a quality mattress, these will be natural fibres, whereas in cheaper entry-level models this may be polyester or foam. Either way, these comfort fibres will start to settle once you’ve slept on the bed for a while as they compress into position.

This means that, initially, body impressions would be more visible as the mattress fillings directly beneath the user are compressed. This article explains why settlement and indents in mattresses can be reduced by following some simple steps.

• What is mattress settlement?
• Why is my mattress sagging?
• How to stop your mattress dipping
• Top tips to fix mattress settlement
• Mattress types and how to avoid dipping
• How mattress upholstery will affect sagging

What is mattress settlement?

Mattress settlement is where the fillings of a mattress compress and ‘settle’ into position. As you sleep in the same space most nights, mattress settlement tends to occur quicker in that space than in the rest of the mattress. It’s like only sitting on one side of the sofa; when you try the other side it may feel plumper or firmer.

Mattresses with very soft layers such as Wool, Alpaca or Cotton, are more prone to settlement. Therefore, constant twisting and rotating of the mattress whilst new is extremely important to even out the wear pattern to reduce and prevent undue settlement.

Even Vi-Spring, one of the premier mattress manufacturers, gives essential information advising that initial body impressions are not a fault of the mattress but an intrinsic part of the mattress bedding in period.

In our experience, settlement can be a cause for unnecessary concern. It shows itself more in mattresses with a bigger span area, such as king-size or super king sizes.

Why is my new mattress sagging?

Mattress sagging is usually caused by lack of mattress care, where the sleeper uses the same part of the bed each night, thereby causing the fibres to eventually sag from overuse.

It stands to reason that, as you are only sleeping in an area the width of your body, the central and perimeter areas will be underutilised. After a few weeks, it may look like the sleeping areas are wearing quicker than the rest of the mattress, but constant turning, rotating and using different parts of the sleeping area will (in time) equal out this pattern.

Funnily enough, cheaper end mattresses with minimal layers of wadding tend not to show body indents, as there is so little wadding and upholstery to indent that you tend not to notice it more readily. However, the lack of upholstery causes all sorts of long term problems as there’s usually not enough comfort layers to provide relaxation during the night.

Of course, cheaper end mattresses will more than likely be polyester-based and, as polyester has a low rate of recovery and not a very long lifespan, you will soon be primarily be sleeping directly on the spring unit.

Whilst this is completely natural and expected, there are tips you need to be aware of to help prevent this settlement from turning into lumps and bumps. A few years ago the National Bed Federation (NBF) & Sleep Council noted that retailers were not informing customers that all new mattresses, in particular, high-end mattresses were subject to settlement. So it’s important to take steps to prevent excessive mattress settlement.

For sleepers experiencing excessive settlement, firmer pocket-sprung mattresses can help distribute weight more evenly and reduce long-term compression. By providing stronger core support, firm mattresses are often better suited to maintaining shape and alignment over time.

This is where natural fibre pocket sprung mattresses differ significantly. Natural fillings such as wool and hair have far better recovery properties than synthetic fibres, allowing the mattress to settle evenly without collapsing or forming permanent dips. Combined with individual pocket springs, this construction supports long-term comfort while reducing the visible and structural issues associated with cheaper polyester-based designs.

How to prevent mattress settlement

Firstly not many people realise that the underlying layers used in the mattress will have an effect on how they settle. Pillow tops are the absolute nightmare construction method as you can’t avoid settlement. Once the permanently attached soft pillowtop compresses, there’s no way to turn or remove this. So we always advise steering well clear of these types of models.

Turning and rotating your mattress monthly is essential.

Mattresses that are full of natural fibres will need more care and attention than cheaper foam-based models but they will last significantly longer. Sometimes, this gap can be up to 15 years vs 3 years before a foam mattress has completely compressed.

Foams as a bridging or insulating layer are extremely resilient to compression. With our Origins range we always add an inch layer of Reflex foam above the spring unit, as the resilient bridge/dampener between the springs and the softer primary comfort layers. If this was not there, then when you are compressing the comfort layers you will be doing so directly on the springs with absolutely nothing taking the strain. You need to bear in mind the fact all foams are far warmer than natural fibres, so if you’re a hot sleeper you need to bear this compromise in mind.

Absolute high-end mattresses with natural fibre upholstery, rather than polyester, utilise components such as Horsehair, Mohair, Coir, Bonded Wool and Cotton, Cashmere blends. These offer unparalleled levels of lasting comfort and breathability.

These fibre layers are entirely ‘forgiving’ and move in conjunction with the sleeper and the spring unit. These components are also completely and utterly fail-safe, meaning that there is no possible way they can be depressed to such a level as to not return to their original loft. However, they do need some assistance to help even out their settlement and shake them back to life during the life of the mattress.

Top tips to avoid mattress settlement

• Turn and rotate your mattress monthly (even if it looks fine).
• Avoid Pillowtop Mattresses as these can’t be turned.
• Buy a 2-sided mattress and avoid ‘No turn’ models.
• Add an additional natural fibre topper to help take the strain of the top layers.
• Change your sleeping position and side to help even out wear.

How mattress types are affected differently by settlement

The type of mattress you buy will have a huge effect on the speed in which they will settle and the options you have to try and reduce this. The table below will show you what to expect and how to fix it. Bear in mind that the time until dipping is if nothing is done to maintain or look after the mattress.

Mattress Type	Fibre Type	Expected Lifespan before potential dips if not maintained	Can the settlement be prevented?
Open Coil / Traditional Bonnell Spring Mattress	Synthetic	2-3 Years	Partly with the addition of a topper and turning monthly
Memory Foam / Mattress in a box Mattress	Synthetic	3-4 years	Not usually - they are one sided so can only be rotated
Hybrid Foam Mattresses	Synthetic	5-6 years	Not usually unless 2-sided
Latex Foam Mattresses	Synthetic/Natural	8-10 years	Yes turning and rotating
Synthetic Pocket Spring Mattresses	Synthetic	8-10 years	Yes by turning & rotating
Natural Fibre Pocket Spring Mattresses	Natural	10 Years +	Yes by turning & rotating