Bonnel Spring vs Pocketed Spring Mattresses: What Changes for the Felt Layer

Two spring beds, two different jobs for the felt

Felt sits in the same place in both constructions — between the spring core and the comfort layers — but a bonnel-spring unit and a pocketed-spring unit ask different things of it.

A

Bonnel Spring — continuous, interlinked coils. Felt bridges the open structure and distributes load evenly.

B

Pocketed Spring — individually wrapped coils. Felt cushions each pocket without restricting independent movement.

Bonnel spring: bridging an open coil structure

Bonnel-spring units are continuous, interlinked coils — the whole spring bed moves somewhat as one unit. The felt layer’s main job here is to bridge the open structure of the coils so you don’t feel individual wires through the mattress surface, while distributing load evenly across the linked coils.

Pocketed spring: isolating and cushioning independent coils

Pocketed-spring units are individually wrapped coils that move independently, which is what gives a pocketed-spring mattress its point-elasticity and motion isolation. Felt here has a different job: cushioning and insulating each pocket without dulling that independent movement — too dense a felt can start to work against the isolation the pocket construction is designed to give.

What this means for your specification

Neither spring type demands a fixed GSM — see how to choose mattress felt GSM for how GSM tracks firmness and durability generally. What changes with spring type is the balance: bonnel-spring builds usually lean toward a felt that prioritises even load distribution across the linked structure, pocketed-spring builds usually lean toward a felt that cushions without restricting each pocket’s movement. Hard cotton mattress felt is made to order for both.

Tell us which spring construction you’re building on, along with your target firmness — we’ll recommend the GSM and density from there rather than starting from a fixed number.