What Is Flannel Fabric?
Flannel fabric is a woven cloth, in plain weave or twill weave, that has been brushed so that tiny fibre ends stand up from the surface. This raised layer, called the nap, traps air, which gives flannel its soft handfeel and its warmth. Flannel can be napped on one side or both. It is made from cotton, wool, viscose, polyester or blends, so the name describes the finish and feel, not the fibre.
In the UK, flannelette is the term most often used for a lighter, cotton-based flannel, usually brushed on one side and used for bed linen and nightwear. Flannel proper tends to describe the slightly heavier cloths used in shirts and trousers, and wool flannel is a separate, traditional cloth with a different character. Because the labels are used loosely in the trade, always define the fibre, weight and brushing in writing.
If you are new to woven structures, our woven vs knit guide explains why a woven flannel behaves so differently from a knitted fleece.
How Flannel Is Made: Weaving and Raising the Nap
Flannel starts as ordinary woven cloth. Producers often use softer, more loosely twisted yarn, particularly in the weft, because it lifts more easily when brushed. The fabric is woven in plain weave, or in twill, which has a diagonal line and a slightly softer drape. You can read more about that structure in our twill fabric guide.
After weaving, the cloth is cleaned and often dyed. Plaid and check flannels are usually made from yarn that is dyed before weaving, so the pattern is woven in rather than printed. The cloth then passes over rollers covered in fine wire or abrasive surfaces that tease fibre ends out of the yarn. This is called raising or napping. A finishing pass may trim or smooth the nap, and the cloth is usually pre-shrunk to limit later movement.
Typical stages in producing flannel fabric
- Yarn and weavingSoft-spun yarn is woven in plain or twill structure, often in yarn-dyed checks.
- Preparation and dyeingCloth is cleaned, then dyed in the piece unless the yarn was already coloured.
- Raising the napRollers lift fibre ends on one or both faces to create the soft surface.
- FinishingThe nap is trimmed or set, and the cloth may be compacted to reduce shrinkage.
- InspectionRolls are checked for shade, weight, width and surface faults before cutting.
A generic sequence. Mills vary the order and the details.
The extent of brushing is a specification choice. Light brushing gives a drier, smoother hand and less lint, while heavy brushing gives a plusher feel but more surface fibre to shed and to pill.
Fibres: Cotton Flannel, Wool Flannel and Blends
Cotton is by far the most common fibre for casual flannel because it is soft, breathable and takes yarn-dyed checks well. Cotton flannel is the basis for flannel shirts and pyjamas, and the term brushed cotton is often used for the same thing. A cotton-rich flannel suits everyday wear, though it can shrink more than blended alternatives unless it has been treated.
Flannel fabric by fibre
| Fibre | Character | Typical uses | Points to watch |
|---|---|---|---|
| Cotton | Soft, breathable and warm without bulk | Shirts, pyjamas, casual trousers, linings | Shrinkage and lint; heavy brushing can pill |
| Wool | Warm, springy and traditional; the fibre differs from cotton in many ways | Trousers, jackets, skirts | Outside typical casualwear production; care and sourcing need specialist knowledge |
| Viscose or viscose blends | Fluid drape and soft hand | Shirts, dresses | Weaker when wet; see our viscose guide |
| Polyester or poly-cotton | Stable, fast drying, less shrinkage | Workwear shirts, linings, budget lines | Can feel less breathable and may pill more |
General characteristics only; construction, finishing and yarn quality shift every row.
For wool flannel, our wool fabric guide sets out the fibre and its handling. Most buyers seeking a flannel shirt or pyjamas will be specifying cotton or a cotton blend.
Flannel Fabric Weights: Typical GSM Ranges
Flannel is sold by weight in grams per square metre (GSM), or sometimes ounces per square yard. A lighter flannelette suits nightwear and summer shirts, a mid weight suits flannel shirts, and a heavier cloth suits overshirts and trousers. The chart shows typical bands to help you brief a supplier; real fabrics vary by mill and by how heavily they are napped.
Typical flannel fabric weights by use
Typical grams per square metre
Typical ranges only; they vary by product, mill and market. Wool flannel is shown in a separate colour because it is a different fibre and category.
Always confirm whether a quoted GSM refers to the greige cloth or the finished, napped, washed cloth, because brushing and finishing can change the weight. Our fabric GSM guide covers how weights are measured and why they matter.
Flannel vs Fleece vs Brushed Jersey
Flannel is often confused with other soft, warm fabrics. The key differences are structure and stretch. Flannel is woven and stable. Fleece and brushed jersey are knitted, with loops that stretch. The table separates the three, which helps when a customer says they want a flannel feel in a hoodie or a fleecy feel in a shirt.
Flannel fabric compared with similar warm fabrics
| Property | Flannel (woven) | Fleece (knit) | Brushed jersey (knit) |
|---|---|---|---|
| Structure | Woven plain or twill, napped | Knitted, brushed on the back | Single jersey brushed on one side |
| Stretch | Little unless elastane is added | Stretches in both directions | Stretches in both directions |
| Shape and structure | Holds crisp collars, cuffs and plackets | Soft, casual shape | Soft and drapey |
| Edge finish | Frays at cut edges | Curls but does not fray | Curls but does not fray |
| Pattern | Yarn-dyed checks and plaids are typical | Mostly solids or prints | Mostly solids or prints |
| Typical garments | Shirts, pyjamas, trousers, linings | Hoodies, joggers, jackets | Loungewear, tops, leggings |
General tendencies. See our fleece fabric guide and polar fleece vs sherpa for the knitted side.
A good rule is to choose flannel where a shirt needs structure and a woven check, and to choose fleece where stretch and an easy casual shape matter more.
Indicative Ratings: How Flannel Fabric Performs
The ratings compare typical cotton flannel with a poly-cotton flannel and a midweight cotton poplin shirting for reference. They are indicative of general behaviour, not test results, and finishing can change any score.
Flannel fabric performance (indicative)
1 dot = low, 5 dots = high
| Cotton flannel | Poly-cotton flannel | Cotton poplin (reference) | |
|---|---|---|---|
| Softness | ●●●●● | ●●●●● | ●●●●● |
| Warmth | ●●●●● | ●●●●● | ●●●●● |
| Breathability | ●●●●● | ●●●●● | ●●●●● |
| Shrink stability | ●●●●● | ●●●●● | ●●●●● |
| Pilling resistance | ●●●●● | ●●●●● | ●●●●● |
| Low lint and shedding | ●●●●● | ●●●●● | ●●●●● |
Indicative ratings based on typical fabric/process characteristics, not laboratory results.
Cotton flannel wins on softness and breathability but needs more care over shrinkage and surface fibre. Poly-cotton is steadier and easier to launder, at the cost of some handfeel and a higher tendency to pill.
Cutting, Sewing and Pattern Matching Flannel
Flannel is relatively easy to sew, but several points need planning. The nap makes the cloth slightly thick at seams and plackets, and lint builds up on cutting tables and machines, so tidy housekeeping matters. Because the surface can shift, a fine, sharp needle and a suitable stitch length help avoid puckering. Collars and cuffs often use interfacing to keep their shape; see our interfacing guide.
Pattern matching is the major cutting issue with plaid flannel. Checks must line up across the front placket, the pockets, the yokes and the sleeves, so the fabric needs a defined repeat size, and the cutter needs to allow extra yardage for matching. Skew, where the check runs off the straight grain, makes matching difficult, so confirm tolerance for skew and bowing with the mill. Our gingham fabric guide covers check matching in more depth.
Flannel cutting and sewing checks
- Check size or repeat is defined, and the cutter allows extra fabric for matching
- Maximum skew and bow are agreed before cutting
- Nap direction is consistent across all pieces if the surface has a visible direction
- Needle size and stitch length are tested on the actual flannel fabric
- Seam allowances at thick junctions are checked for bulk and comfort
- Lint is controlled in the sewing and finishing areas
Agree these in the sample stage, not after bulk cutting has begun.
Shrinkage, Pilling, Lint and Care
Cotton flannel can shrink noticeably in the first wash, particularly if the cloth was not pre-shrunk, and the brushed surface can make shrinkage in length more obvious. Ask the mill whether the fabric has been finished to limit shrinkage, and ask the factory to run a wash test at the care-label temperature on the actual cloth. A wash test also reveals skew movement and colour bleed, which matters for dark yarn-dyed checks. Our garment testing guide lists what to request.
Pilling and lint come from the surface fibres. A heavier nap produces more loose fibre, and pills form where friction rubs fibres into balls, for example at underarms and cuffs. The effect is stronger in blends where synthetic fibres hold the pills on. For the causes and test grading, see our guide to fabric pilling.
Care is usually simple: wash at the temperature on the label, avoid overloading the machine, and use moderate heat when drying, since tumble drying is a common cause of shrinkage. Flannel gets softer with washing, but the first wash is when most movement occurs.
Flannel for Nightwear: A Safety Note
Flannel and flannelette are popular for pyjamas and nightwear, and the napped surface needs particular attention. Raised cotton surfaces can burn more readily than smooth ones, and UK nightwear, especially for children, is covered by safety requirements on flammability and labelling. We do not quote the rules here because they are detailed and can change. Before any nightwear is developed, confirm the current requirements with the factory, a test house or Trading Standards, and ask which fabric treatments or constructions are used to meet them. Our pyjamas manufacturing guide covers the wider development process.
How to Specify Flannel Fabric and What to Check on a Sample
A clear specification avoids disputes, because flannel can be sold under many names. Write down the fibre content, weave (plain or twill), finished weight in GSM, which side or sides are brushed, the dye method (yarn-dyed or piece-dyed), the check size where relevant, width, and the shrinkage and colour fastness requirements. Then check the swatch against the list below.
Five checks on a flannel swatch
- 1Handle the napRun a hand over both faces. Is the brushing even and as plush as you expect?
- 2Check the weightWeigh a cut sample to confirm the finished GSM against the spec.
- 3Wash itWash at the care-label temperature and measure shrinkage, skew and colour bleed.
- 4Rub itRub the surface to see how quickly it sheds lint or starts to pill.
- 5Match the checkLay two cut panels edge to edge to see whether the pattern can be aligned.
Ask for a written wash result, not only a verbal assurance, and compare the swatch to the bulk fabric if a mill offers a lab dip or strike-off before production.
How Ruhrose Approaches Flannel
Ruhrose develops woven cotton casualwear alongside hoodies, jersey and denim, produced in Bangladesh with UK buyer support. Flannel shirts and similar brushed cotton items are within that casualwear area, but availability of a given flannel quality, check or weight depends on the project, so we discuss it case by case and approve fabric and fit on samples before bulk. Wool flannel tailoring and certified nightwear are outside our core, and we will say so early. If you are comparing structures, our twill guide is a helpful companion.