The Anatomy of a Sleep Set
The function and performance of a sleep set is determined by five factors: the ticking, comfort zone, support system, foundation and bed support.
1. Ticking
The mattress fabric or ticking is the outside layer of the mattress. Ideally, it should be both sturdy and soft. 2. Comfort Zone
The comfort zone is made up of the upholstery material between the support system and the ticking. This can be composed of a variety of materials such as felt, foam and fibre pads. 3. Support System
The support system is the inner structure of the mattress. Most manufacturers have their own exclusive support structure variations, but most derive from five types of support: high-density foam, open coils, offset coils, pocket coils, and continuous coils. 4. Foundation
The foundation is the bottom portion of the sleep set. Its purpose is to support the mattress, help absorb impact to the mattress and help prolong the life of the mattress. 5. Bed Support
A sleep set must be properly supported, both for durability and to maintain the validity of the warranty. Bed rails or a bed frame can provide support. It is important that the sleep set has adequate support for its size (see Help Extend the Life of Your Mattress).
Mattress Set Construction
Mattress
A mattress is made up of a support system, comfort zone and ticking. Support System
There are several types of support systems, but the two most popular categories are foam and innerspring. Foam
Foam mattresses have several advantages. They are lighter in weight than innerspring mattresses and are easier to move and position. Foam is often a good choice for allergy sufferers, especially if the foam is mildew and dust-resistant. Foam mattresses have little side-to-side sway, so you're not disturbed when your partner changes sleep positions. Because foam is flexible, a foam mattress is a good option if you want a queen-size or king-size bed but may have trouble getting the mattress up a set of stairs or around a tight corner in your home. Many consumers consider foam to be an inexpensive material; however, the price of a good quality foam sleep set compares to that of a good quality innerspring set. Innerspring
Innerspring mattresses have wire coils as the support structure. An innerspring mattress has a strong border wire attached to the perimeter of the coils. The border wire supports the coils, helping to retain shape and reduce sagging. The edge is reinforced with specially shaped springs or foam to support the sleep surface right to the edge, to help prevent 'rollout' and edge breakdown. The upholstery is separated from the innerspring system by an insulator, a tough padding, wire or netting layer that prevents the upholstery from sinking into the coils. Support System
There are several types of support systems, but the two most popular categories are foam and innerspring. There are a number of different types of coils: 1. Open Coil
This hourglass-shaped wire coil is joined to adjacent coils by small wire spirals called helicals. The open coil design provides good initial support but these coils fatigue more quickly than more technically advanced coil constructions. You'll know this mattress has reached the end of its life when 'roll together' or 'hammocking' occurs. 2. Offset Coil
This coil construction is similar to the open coil but it has a squared head, which allows it to contour better. An offset coil is slightly more cylindrical in shape than an open coil, which increases its durability. It is also laced to its neighbours by helicals. 3. Pocket Coil/Independent Coil
A pocket or independent coil is a cylindrical spring wrapped in its own fabric pocket. This construction is designed to give the most contour of any support system. Each coil works independently of the ones around it, so you are less disturbed when your partner shifts sleep positions. Each coil in this construction must absorb the weight placed on it without distributing the load to its neighbouring coils. This means that the coils will provide less support over time, particularly for heavier people. 4. Continuous Coil
The continuous coil is exactly that - each row of coils is made of a single wire attached to the next row by helicals. This type of coil is often made into a honeycomb of coils rather than straight rows, allowing more coils per mattress than most other constructions. This design allows each coil to deflect weight to a great number of springs. With less stress on each coil, they keep their shape longer.
Comfort Zone
The comfort zone, between the support system and the ticking, is made up of two groups of materials: the quilt assembly and the upholstery layers. 1. Quilt
The top layer of materials on the mattress is the quilt. The quilt is made up of one or more foam and fibre layers stitched between the ticking and a quilt backing. The quilt can range from a tight firm surface to a thick pillow-top. 2. Upholstery
The upholstery layers are located between the support system and the quilt. The upholstery is often made of foam, cotton felt and fibre pads. Upholstery can be used in an almost unlimited number of combinations to create anything from a "hard-as-rock" feel to a "floating-on-clouds" feel. An insulator of heavy fibre or mesh keeps the upholstery from sinking into the coils. Ticking
The ticking has a lot to do with a sleep set's appeal, often featuring soothing colours and textures. Popular ticking fabrics are cotton blends, polyester knits, chintzes and damasks. As a rule of thumb, the more luxurious a fabric, the more it costs to produce. Foundation
The foundation is the component of a sleep set that has a significant impact on durability; it is designed to absorb and distribute the weight from the mattress to help prolong the useful life of the mattress. The foundation also raises the mattress to a desirable height. A foundation is often made of a wooden frame and may feature additional steel reinforcements to provide strength. A supporting structure is attached to the frame, usually a strong wire coil or grid. Ticking is applied to the sides and a skid-resistant fabric to the top. The bottom of the foundation is covered a fabric dust barrier. There are five types of foundations:
Posture Box
The posture box is a wooden frame with a flat top, covered with the same ticking as the mattress. This construction is the least expensive to make. The posture box has no springs and does not work effectively to absorb the weight from the mattress. A mattress on a posture box foundation will have a shorter lifespan. Semi-Flex Grid
The semi-flex grid is a wooden frame with a rigid metal wire grid attached above supporting slats. The semi-flex grid is firm and minimizes flex to support the mattress. Foam
The foam foundation is made of good density foam and is used to support a foam mattress. This low-noise foundation provides an even distribution of weight from the mattress, helping prolong the mattress life. Coil Spring
This foundation, also known as a box spring, uses a spring coil system to support the mattress. The large cone-shaped coils are made of a heavy-gauge wire to help absorb impact to the mattress. The coil spring foundation provides better support and a softer feel than the more basic foundations. A coil spring foundation tends to have some side-to-side sway under stress, which may cause some uneven wear to the mattress. Modular Grid
The modular grid, or torsion grid foundation, is considered by many to be the best support for a mattress and is used in the best quality sleep sets. Heavy-gauge square coils are attached to a wood frame, which tends to have more slats than less expensive foundations. The square coils evenly absorb the torsion of the weight transferred to them, and help prolong the life of the mattress in an effective manner. Bed Frames
What type of support does a sleep set need? This is especially important to know for larger bedding where improper support can result in twisting or sagging of the sleep set. The side rails of a bed frame provide adequate support for twin and double-size sleep sets. A queen-size or king-size sleep set requires extra support. Select a frame that has a centre support rail with extra legs, such as six instead of the standard four legs. Make sure you understand the correct support required for your mattress set. Inadequate support will invalidate the sleep set warranty.