Innerspring mattresses are made of multiple layers, the most important layers being the innerspring unit and the insulator pad. The innerspring unit is made of coils and border rods. Coils make up the main body of an innerspring mattress. The number of coils and the thickness of those coils are part of what indicate a quality innerspring mattress.
The actual number of coils can indicate quality, but it is the number of coils and the thickness of those coils that is important. Crib mattresses with 150 coils or less typically have a 13.5 gauge carbon tempered steel coil or thicker. A crib mattress with more than 160 coils will usually use a lower gauge steel coil. There is not enough room inside the mattress to increase the number of coils at the same gauge. A lower weight coil can create a softer crib mattress. Keep in mind, the best innerspring mattress almost always has the higher amount of steel, including coils and border rods.
Border rods are steel rods, preferably 9.0 gauge steel, which circle the top and bottom edges of the mattress. Border rods provide edge support which is helpful when your baby cruises the crib rail. Border rods also offer even weight distribution over the surface of the mattress which reduces the risk of soft spots or sagging.
The insulator pad lies on top of the coils and prevents the foam cushioning layer from sinking into the coils. The insulator pad can be made of shredded coconut shell formed into a mat or pad called coir fiber. Most commonly, they are made from many different scraps of fabric that are washed, pressed, and almost felted into a pad called a fiber wrap pad. Both types of insulator pads are comfortable, but the coir fiber wears better over time.
Some manufacturers include an extra layer called a permalator, which is a wire mesh that lies directly on top of the coils. It prevents the insulator pad and cushioning materials from sinking into the coils. A permalator layer is generally found on only the higher-end and most expensive crib mattresses.
The foam cushioning layer is the final layer in an innerspring crib mattress. Crib mattresses typically have one foam cushioning layer, while some manufacturers use two foam layers.
- If you're looking for comfortable support, try the Sealy Baby Posturepedic Crib Mattress. This was the mattress that struck my fancy and the eye of many others – our local store sold out. The Sealy Baby Posturepedic crib mattress mixes firm coil support with a soft, non-allergenic foam for a supportive, yet comfortable mattress. The heavy gauge steel border rods which circle the edges of the entire mattress help to evenly distribute weight and prevent the center of the mattress from sagging. This mattress is also protected by an antibacterial and antistatic laminated cover that wipes clean with a damp cloth. The innerspring unit holds up well over time and can be used on a toddler bed once your baby outgrows their crib – a worthwhile investment.