How to select and use interfacing: A simple guide
- Emma Cartmel
- 7 days ago
- 5 min read
Fusible, sew-in, woven, non-woven—interfacing comes in a variety of types, weaves, and weights. But with so many options, how do you know which one to choose?
Fusible, sew-in, woven, non-woven—interfacing comes in a variety of types, weaves, and weights. But with so many options, how do you know which one to choose?
In this post, I’ll begin by explaining the two main types of interfacing before diving into the variations in weave and weight. By the end, you’ll hopefully feel a bit more confident when it comes to selecting interfacing for your next sewing project.
What is interfacing?
Interfacing (sometimes called interlining) is a type of fabric that is applied to the reverse of fabric. It's purpose is to provide stability and structure to a garment, while reinforcing weak spots and areas prone to stretching. As a result, interfacing is commonly applied to areas such as collars, cuffs, plackets, necklines, waistbands, and beneath buttonholes.
Interfacing is available in two main types: iron-on and sew-in. Each have their own characteristics, making them better suited for different fabrics and projects.
Iron-on interfacing
Iron-on interfacing, also known as fusible interfacing, bonds to fabric through the application of heat. On the back of fusible interfacing, you will notice either rough dots or a shiny finish—this is the adhesive layer. When heat is applied, this layer fuses to the wrong side of your fabric. Fusible interfacing works best with fabrics that can tolerate heat, like cotton or linen.
How to apply iron-on interfacing
Applying fusible interfacing is a straightforward process.
Cut the interfacing to match your pattern piece. Make sure the edges line up neatly as overhanging edges can cause the adhesive to stick to your iron or ironing board.
Lay your fabric on the ironing board with the wrong side (the back) facing up.
Place the interfacing on top of the fabric, with the glue side (usually the shiny or rough side) facing down. Carefully align the edges.
Set your iron to a dry setting (no steam) and heat it to the temperature recommended for your interfacing and fabric. Press the iron onto the interfacing in sections, holding it in place for a few seconds at a time. Don’t slide the iron—this can shift the interfacing.
Tip: If you have access to an iron press, it can make this step even easier!
Sew-in interfacing
As the name suggests, sew-in interfacing, also known as non-fusible interfacing, is attached to fabric by sewing rather than the application of heat. It’s ideal for projects where you want to maintain the fabric’s natural drape and texture or when working with delicate fabrics like silk, velvet, or embellished materials that can’t handle heat.
How to apply iron-on interfacing
While sew-in interfacing takes a little more time to apply, it’s just as straightforward:
Cut the interfacing to the same size as your pattern piece. Make sure the edges line up for a smooth finish.
Lay the interfacing on top of your fabric with the wrong sides (the back of both pieces) together. Align the edges carefully.
Pin the interfacing to the fabric to keep it from shifting while you sew. For extra stability, you can baste it in place with a long, temporary stitch.
Stitch the interfacing to the fabric within the seam allowance (the area between the edge of the fabric and the stitching line).
Weaves
Both fusible and sew-in interfacing can be further categorised by their weave type. The three main weaves are woven, non-woven, and knit.
Woven: Woven interfacing is just like woven fabric, with visible warp and weft yarns and a selvedge edge. Since it has a grainline, it’s important to align your pattern pieces parallel to the grainline, just as you would with fabric. This ensures proper drape and strength.
Non-woven: Non-woven interfacing is made by bonding or felting fibres together. so it doesn’t have warp and weft yarns or a grainline. You can cut pattern pieces in any direction, making it more economical and simple to use.
Knit: Knit interfacing is made using interlocking loops, similar to knit fabric, which gives it stretch and flexibility. It’s ideal for knit fabrics, stretchy jerseys, or lightweight woven fabrics with drape. Before cutting, check the direction of the stretch in the interfacing and align it with the stretch of your fabric for the best results.
Fabric as interfacing: As an alternative, lightweight fabrics like organza or cotton voile can be used as interfacing. This method is especially useful for delicate or sheer fabrics where traditional interfacing might be too stiff or visible.
Weights
Interfacing is also available in various weights: light, medium, and heavy weight. Choosing the right weight depends on your fabric and project needs. As a general rule, select an interfacing that matches the weight of your fabric or is slightly lighter.
Lightweight: Lightweight interfacing provides subtle support while preserving your fabric’s natural drape. It’s perfect for delicate fabrics like silk, lightweight cotton, or chiffon.
Medium weight: Medium weight is the most versatile and widely used interfacing. It offers support without sacrificing flexibility, being suitable for fabrics like cotton and linen. This weight works well for structured garment details like collars, cuffs, and plackets.
Heavyweight: Heavyweight interfacing provides substantial stability, often used for more specialised projects like bags, hats, or items that need extra structure. While it’s less common in dressmaking, it’s useful for projects requiring a firm finish.
Tips for choosing the right interfacing for your project
There are no hard-and-fast rules for selecting interfacing—it all depends on your project and fabric. The best advice? Test, test, test! Always try out different interfacing options on scraps of your fabric to ensure you achieve the desired look and feel.
Here are some general tips to help you choose and use interfacing:
Colour matters: Use white interfacing for light-coloured fabrics and black for darker ones to prevent it from showing through.
Prep your fabric: Always iron your fabric first to remove wrinkles, ensuring a smooth application.
Smooth out interfacing: If your interfacing is creased, lightly spray it with water and let it dry flat before use.
Fusible interfacing:
Use a pressing motion (lift and lower) instead of sliding the iron back and forth to avoid distorting the fabric.
Let the fabric cool completely before sewing to ensure a secure bond.
Protect both your fabric and iron by using a pressing cloth.
Interface first, cut later! Fuse the interfacing to a larger piece of fabric before cutting out your pattern pieces. This is especially helpful for slippery fabrics or small, fiddly pieces.
Trim to reduce bulk: For heavier fabrics, cut fusible interfacing slightly smaller than your pattern piece. For sew-in interfacing, trim close to the stitching line after attaching it to reduce bulk.
Recheck pattern markings: After applying interfacing, revisit any notches, darts, or other markings to ensure they’re still visible.
When in doubt, ask! Check the manufacturer’s instructions or ask for advice at the store where you purchased your interfacing.
Choosing the right interfacing is key to the success of your sewing project. Whether you opt for fusible or sew-in, it’s essential to consider the fabric type, weight, and the structure you want to achieve. The right interfacing helps your fabric hold its shape and gives your project that professional finish.
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Thanks for reading.
Emma xx
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