Just as for any woven fabric with stretch, a lengthwise stretch fabric is increased in comfort and durability. Because the stretch is on the lengthwise grain, rather than the crossgrain, it may be a bit perplexing to know how to use this fabric. Aside from a few special techniques, this fabric is equally as easy to work with as any stretch woven.
Depends on the base fabric. Most of these fabrics are tightly woven, and can be machine washed in cold or cool water. Dry flat, or in a cool dryer. Avoid the use of high heat, as the lycra does not respond well to high heat.
Use the size needle required for the base fabric. If it is a fine suiting, use a 75/11 or a 70/10 needle. If it is a denim with lycra, change to a larger needle such as a 90/14. Use cotton, cotton/polyester, all polyester, or even silk thread for construction.
Standard straight seams (2.0-2.5 length) are good choices for most construction. Hems can be done by machine blind-hemming, hand stitching, or machine topstitching. Seam finishes will vary; test your fabric with a 3 thread serged finished, a seam binding, or use an enclosed seam such as a fell seam or French seam.
Because lycra does not respond well to high heat, a cool-fuse interfacing is the preferred choice. Try So-Sheer or Touch-of-Gold for most areas that require interfacing. If you have an area that needs a crisper interfacing, use a sew-in interfacing (such as batiste, organza, or muslin) cut on the bias.
Tailored garments such as jackets, coats, trousers. Casual garments: pants, tops, capris, tanks, cardigans.
Because the stretch of the fabric is on the length of the fabric, the crossgrain is quite stable. You can use the lengthwise grain to make piping or inserted fringe, using the lengthwise stretch to curve around areas of the garment that need shape.
Many of these fabrics are striped or have border prints. The lengthwise stretch will allow you to cut the garment on the crossgrain, if you like, taking advantage of the comfort factor of the stretch of the fabric. You can then use the crossgrain (which is stable, not stretchy) for areas that need stability, such as plackets, collars, pockets, and cuffs. Avoid high heat with the iron, and use a press cloth when pressing seams.