Silk Fabric

• Because silk is a natural fiber, it is susceptible to humidity. As with most natural fibers, it will shrink a bit when the air is dry and stretch and plump up a bit in humid situations. Unfortunately, the amount it will shrink and plump is not known for certain; drape makers will often assume the drapes will stretch and allow for that in their construction.
  
  

Linings

• The lining can be used to act as a stabilizer for the silk. Attach the two by hand-sewing the layers together at the vertical seams. Try to use long --- 1/2 inch or more --- running stitches that just catch the silk and secure it to the lining. Stitch the layers together up from the bottom edge to within 2-1/2 feet of the top.
  
  

Move the Rod

• Before you decide to shorten the drapes, try to determine if they are stretching due to humidity or their overall weight. Check the length of the drapes on a rainy day and check it again on a dry day. If there is no appreciable difference, the solution may be as straightforward as moving the curtain rod.
  
  

Rehem

• If moving the rod is not an option, and you need to have the drapes rehemmed, a professional drapery maker should measure the drapes while they are hanging in your home. The new hem may not be on the straight of grain of the fabric, so extra care must be taken when measuring.