- Standard crib mattresses measure 51 5/8 inches by 27 1/4 inches.
- Crib mattresses are made standard to fit snugly into today's cribs. If a crib is going to be re-used, be sure to measure the crib and mattress to insure a proper fit.
- A mattress must fit snugly inside the crib. You should not be able to easily put two adult fingers between mattress and side of crib. Too much room between the mattress and crib rail will cause an entrapment hazard increasing the risk of injury and suffocation.
- Crib mattresses should never be more than 6 inches thick. A thicker mattress would sit too high in the crib creating the risk of a fall. The distance between the top of the mattress when sitting at its lowest point and the top of the side rail at its highest point, must not be less than 20 inches.
Generally there are two choices when deciding on a crib mattress, innerspring or foam. To test the firmness of a mattress, press the sides, middle and corners of the mattress. It should not give much and should bounce back quickly.
Foam mattresses are usually lighter weight than innerspring (making sheet changes easier), but you always want to look for the highest-density foam (which adds to the weight of the mattress) to provide the most firmness. Since there is no metric to measure density, the best way is to physically compare yourself. When pressing into a foam mattress, it should bounce back to form quickly.
Innerspring mattresses have a spring unit at its core made up of steel coils ranging in both quantity and thickness. Surrounding the spring unit is the Insulator padding that can include coir fiber or Permalator mesh. On top of the Insulators sit the cushioning layers, made up of one or more sheets or foam, cotton batting, or cloth. Innerspring mattresses usually last longer than foam. Features to consider specific to purchasing an innerspring mattress:
- Steel gauge of coils and border rod. Remember, the lower the gauge, the thicker the steel.
- Number of coils - the more, the better.
- A border rod is a steel rod that runs along the edges of the mattress to help keep the edges of the mattress from sagging over time.
Innerspring mattresses also have Insulator padding to protect against the steel coils. This is a pad that lies on top of the coils, preventing the cushioning layer and cover from sinking into the coils over time. Most common type of insulator pads:
- Coir fiber which is a strong, all natural padding made from coconut husks.
- Permalator wire mesh that offers even stronger support than coir fiber but is not natural. This is a wire mesh that lies directly on top of the coils.
- Cotton padding.
- Cloth padding which is the least expensive insulator pad but still works well.
On top of the insulator padding of an innerspring mattress is the cushioning layer for comfort. This layer is generally made up one or more foam pads, cotton or polyester.
- Thin layer(s) of foam adds comfort without losing firmness.
- Some mattresses have memory foam for additional comfort.
The mattress cover, also known as Ticking, can be a major factor in the longevity of the mattress.
- Quilted vinyl or multiple layers of laminated vinyl reinforced with nylon provide enhanced durability and water resistance.
- Single layered covers tend to be less expensive, but will not last as long.
- Look for mattresses with flame retardant covers.
- Some mattresses also feature tear-resistant and anti-bacterial covers.
There are generally two types of vents, the smaller eyelet vents that run along the sides of the mattress and the larger round vents that usually have one or two on two sides of the mattress.
There are two schools of thought regarding vents:
- Vents allow air to flow through, keeping the mattress fresh.
- Vents allow the mattress to breath with baby's movement, reducing stress on seams.
- Having no vents keeps airborne particles from getting inside the mattress.
- You'll find the term Organic Mattress. While a mattress may not technically be organic since it is not an agricultural product, there are mattresses produced where potentially harmful chemicals are eliminated in favor of organic and non-toxic materials.
- Dual Firmness allows you to use the mattress into the toddler years. Dual Firmness Mattresses have a more firm side for infants to reduce the risk of SIDS and help promote bone growth, and a less firm side for toddlers (over one year old) which still gives support, but adds more comfort for the older child.
- No Flip mattresses are extra durable, designed to never need to be flipped or rotated for the life of the mattress.