What Is Felt Fabric? Wool Felt Types, Thickness, and How to Choose

Felt fabric is a non-woven textile made by matting, condensing, and pressing fibers together rather than weaving them. Wool felt is made from 100% wool (a natural fiber) and can be pure or blended with cotton or synthetic fibers like polyester. To choose the right felt, match three things to your task: fiber type (wool, cotton, polyester, or blend), hardness grade (soft, medium, hard, extra-hard), and thickness (from 1 mm up to 30 mm and more). The form you buy—sheet, roll, strip, board, ring, or tubular—follows from the same decision.

Wool Felt vs. Other Felt Types

The fiber determines performance. Wool felt uses 100% wool, which is natural and takes color well; natural wool is off-white cream, and grey and black are also standard. Cotton felt blends wool with cotton, and polyester felt uses synthetic fiber. When you need a natural fiber with good density and finish, wool felt is the reference material; when cost or specific synthetic properties matter, blends and polyester are the alternatives. The manufacturer's stock covers all of these, so the choice is yours to specify.

Reading Thickness

Felt thickness is quoted in millimeters, centimeters, or inches. Standard production starts at 1 mm and runs to 30 mm and beyond. Common thick-felt inch sizes are 1/8", 1/4", 3/8", 1/2", 3/4", and 1 inch. For thin gaskets and washers, work in the low millimeter range; for padding, packing, and heavy-duty sealing, the thicker inch sizes apply. Always confirm the unit—mm and inch are both in common use and a misread unit is the most frequent ordering error.

Choosing Hardness

Wool felt is manufactured in four hardness grades:

Pressed felt—wool fibers compressed under heavy pressure—is the process behind compressed felt, and technical felt is precision-grade felt made to IS 1719 specification for mechanical applications. If your part must hold shape under pressure, specify hard or extra-hard and pressed or technical grade.

Selecting the Form

Wool felt is first made as a sheet, typically 4–7 meters long (longer on request) and 1.5–2 meters wide. From there:

• Roll – the sheet rolled up for continuous use
• Strip / tape – sheet cut to a required width
• Board / tile / panel – square or rectangular pieces
• Circle / plate – round cut shapes
• Plug / ring – small die-cut pieces
• Cord / rope – felt turned into rope form
• Endless felt – tubular felt pipe mounted on rollers and pipe, also used as a felt belt

Choose the form closest to your finished part to reduce waste; die-cut plugs and rings are already available for gasket and washer work.

Matching Felt to the Application

Industrial uses center on noise and sound absorption, vibration reduction, and insulation, plus gaskets, seals, washers, packing, wicks, and polishing felt. Home uses draw on the softer grades. A practical rule: soft and medium for sound, vibration, packing, and polishing; hard and extra-hard pressed or technical felt for gaskets, seals, and washers that must resist compression.

A Quick Selection Checklist

1. State the fiber: 100% wool, cotton blend, or polyester.
2. State the hardness grade.
3. Give thickness with its unit (mm or inch).
4. Name the form and dimensions (sheet, roll, strip, ring, etc.).
5. Note the application so the grade and process (pressed, needle punch, woven, technical) can be confirmed.

Buying from a felt shop with large stock and variety means these specifications can usually be met from existing inventory; confirm grade and process against your application before ordering.