How to Felt Knitting — Intentional Felting Guide

Felting strikes fear into most knitters — it's what happens when your favourite wool sweater accidentally ends up in a hot wash. But controlled felting is an entirely different story. It's a deliberate technique that transforms loose knitted fabric into dense, warm, sculptural material that doesn't fray, doesn't need seaming, and can be cut like fabric. Here's how to do it on purpose.

What Felting Actually Is

Wool fibres have a microscopic scale structure that, under heat and agitation, causes the scales to interlock and lock together permanently. The fibres tangle and compress, and the resulting fabric is much denser, thicker, and smaller than the original knitting.

This is why felting is usually a disaster — and why, when you want it to happen, it's genuinely useful. Felted fabric is incredibly durable, naturally water-resistant to a degree, and requires no finishing at cut edges.

What Yarn You Must Use

Not all yarn felts. Only 100% non-superwash animal fibres felt reliably:

• 100% non-superwash wool — the easiest to felt
• 100% non-superwash merino
• 100% alpaca (felts, but more slowly and softly)
• Wool/alpaca blends

Do not attempt to felt:

• Any yarn labelled "superwash" — the treatment prevents felting
• Acrylic, polyester, or nylon — synthetic fibres don't felt at all
• Cotton, linen, silk — plant and protein fibres without scales don't felt
• Wool/acrylic blends — the acrylic prevents the wool from fully matting, giving an uneven result

If you're unsure whether your yarn will felt, test a swatch first. Knit a small square, felt it, and check the result before committing to a full project.

How Much Does It Shrink?

This is the number knitters always want to know — and the honest answer is: it varies. Felting depends on the yarn, the water temperature, how long it agitates, and whether you're doing it by machine or by hand.

General guidelines:

• Width: Expect roughly 15–25% shrinkage
• Length: Expect roughly 25–40% shrinkage — felting tends to shrink length more aggressively than width
• Thickness: The fabric becomes significantly thicker and denser

Always knit your pre-felting piece significantly larger than your desired finished size. For a bag you want to be 30cm wide × 25cm tall, knit it to approximately 40–45cm wide × 35–40cm tall. Then felt and check frequently.

Machine Felting Method

Machine felting is easier to control than hand felting because the machine provides consistent agitation and temperature.

1. Place your knitted item inside a zippered pillowcase or mesh laundry bag. This catches any fibres that shed and prevents lint from filling your machine filter.
2. Add a pair of jeans or canvas shoes. The friction from the extra items accelerates felting — without something to agitate against, pure wool in water can felt slowly.
3. Set the machine to a hot wash (60°C or higher). Use a small amount of liquid soap — it helps the fibres move against each other.
4. Check every 5–10 minutes. Open the machine, remove the item, and check the size and texture. This is important — you can always felt more, but you cannot unfelt.
5. When the piece reaches your desired size and stitch definition has disappeared (or is at your preferred level), remove it from the machine.
6. Rinse in cool water, squeeze out excess, and shape while still damp.

Some machines make it difficult to stop mid-cycle. Know your machine before you start. If you can't open it mid-cycle, use a shorter cycle and check between complete runs.

Hand Felting Method

Hand felting gives you more control but is more labour-intensive. It works best for smaller items.

1. Fill one basin with very hot water and a few drops of dish soap. Fill a second basin with cold water.
2. Submerge the knitted item in the hot water. Let it soak for a minute to absorb heat.
3. Begin agitating — rubbing the fabric against itself, squeezing, pressing, rolling. Work in one direction at a time rather than randomly.
4. After 5 minutes, plunge the item into the cold water briefly. This temperature shock accelerates felting.
5. Return to hot water and continue agitating. Repeat the hot/cold cycle several times.
6. Check your dimensions frequently. When the piece reaches the target size, rinse thoroughly in cool water and shape.

Shaping After Felting

Once felted, wool is very easy to shape while still wet. This is one of its best properties:

• For a bag: stuff with plastic bags or a box to hold the shape while drying
• For slippers: stuff with crumpled newspaper and leave to dry — the newspaper absorbs moisture and holds the shape
• For a bowl: drape over an appropriately-sized bowl, form around it, and leave to dry

Felted wool holds its shape after drying. If you don't like the final shape, wet it again while it's still fresh (within a day or two) and reshape.

Popular Felting Projects

• Felted tote bags: Knit larger than needed, felt, cut handles or add leather straps. No seam finishing needed because felted fabric doesn't fray.
• Felted slippers: Knit generously sized slippers, felt to fit your foot. The resulting thick felt is warm and durable underfoot.
• Felted bowls: Knit a round bowl shape, felt, and shape over a real bowl while drying. Makes excellent storage or a gift.
• Felted pot holders: Thick felted fabric is excellent insulation.

What to Do When Felting Goes Wrong

If you've over-felted — the item is too small or too dense — there's unfortunately no way to reverse it. Over-felted fabric can still be cut into smaller shapes, used as appliqué, or repurposed into something smaller than originally planned.

If felting is uneven (some areas more felted than others), focus additional agitation on the less-felted areas in subsequent sessions. Hand felting gives you more control for spot-treating areas.

See also: What Is Blocking and Why It Matters — the conceptual opposite of felting, where the goal is to preserve and open the knitting rather than compress it.

Questions about whether your yarn will felt or how to size your project? Ask Emma for help →