Trim coil can ripple as it expands in warm weather. This is a problem only if it is face-nailed in cold weather. In addition to limiting face-nailing, try the following to avoid ripples:

  • Don’t nail too snugly.
  • Hem or crease the material to stiffen it.
  • Drill or punch an oversized hole in the aluminum before nailing.
  • Avoid nailing long fascia and rake pieces. Instead, hold them in place with utility trim and F-channel.
  • On rakes and fascias, install a 1x2 at the top of the trim to provide a stepped profile. This stiffens the trim and limits rippling see illustration, below).
  • To avoid face-nailing a fascia, insert the top of the trim coil under the drip-edge or into a piece of undersill trim and make a 11/4-in. bend at the bottom toward the soffit. Nail up through the bottom leg every 18- to 24-in.
To reduce ripples in aluminum fascia, install a 1x2 to create a two-piece fascia. To keep coil stock stiff, hem the top edge and slip it under the drip-edge.
To reduce ripples in aluminum fascia, install a 1x2 to create a two-piece fascia. To keep coil stock stiff, hem the top edge and slip it under the drip-edge.

For more about installing vinyl siding and trim, visit the JLC Field Guide here.
And for more on exterior trim of all kinds, visit the JLC Field Guide here.