How do I install PVC soffit & trim?

Updated February 21, 2017

PVC soffit is mounted under eaves and overhangs of a house to improve ventilation and the aesthetics of the home. PVC soffits and trim are normally installed when vinyl siding is installed. If the vinyl siding is already installed, you will need to remove the top layer of vinyl siding to install the soffits and trim.

Measure the entire roof fascia to determine how much soffit and trim you will need. You will need an equal amount of F-channel, trim and soffit. An F-channel is a PVC connector that is shaped like a capital "F." These are hung upside down along the fascia and the house. The soffit panels slide through the two prongs to attach to the house. T-channels are shaped like a "T," and the arms of the T cover the corners of the soffit panels. T-channels are needed only at the point where the panels of soffit meet each other. T-channels are not a requirement. The ends of the soffit panels can be mitre cut and placed together. However, the T-channels are easy to use, look professional and are not very expensive.

Measure the F-channels, trim and soffits to fit each section of the fascia and cut it with the tin snips. The F-channels need to be 1/4 inch smaller than total so the soffits fit into the F-channels.

Nail the PVC F-channel to the walls under the fascia where the soffit will sit. The F-channels have predilled nail slots that should be used to nail the F-channel in. PVC will expand and contract during harsh weather. To accommodate this, leave 1/32 to 1/16 inch of the nail exposed. Leave 1/4 inch between F-channels. Continue nailing the F-channels to the wall. The most common installation process starts at one corner of the house and works one wall or side at a time, until all F-channels are installed.

Slide one end of a soffit panel into the F-channel. Bend the panel gently and fit it onto the F-channel on the other end of the soffit. Continue to install the soffit panels until all the eaves are covered.

Nail a section of T-channel, where the corners of the soffit meet. Slide the ends of the soffit into the corresponding side. Both square and mitre cuts work in the T-channel. Squared cuts are easier to install and create less waste.

Attach the trim to the house. PVC trim is nailed to the top edge of the wall just beneath the F-channel. Make sure to leave 1/16 to 1/32 inch of exposed nail to accommodate the expansion of the PVC. Cover all the edges of the F-channel with the trim.

Things You'll Need

  • Tape measure
  • Ladder
  • Soffits
  • Trim
  • F-channels
  • T-channels
  • Corrosion resistant nails
  • Tin snips
  • Hammer
  • Utility knife
  • Snap lock tool
Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Donna Armstrong is a freelance writer who has been writing since 2005. She has provided copy for catalogs, newspapers, newsletters, blogs, informational and e-commerce websites. She has written on a variety of subjects including state-of-the-art electronics and household products. She has worked for such websites as and She attended the University of Texas, where she studied history and education.