How to Install Soffit Under a Porch Roof

JL Wilson

Installing soffit boards on a patio roof system cleans up the look of your outdoor living space. Not only does a soffit finish off the appearance of the patio, but it also insulates and further shields it from the temperature fluctuations.

Patio soffit

While the installation process is rather simple, having the help of a few more hands will speed up the completion as well as make the attachment of overhead boards much easier.

  1. Lay out the project. Study the patio area and measure the distance between the end of the soffit on the fascia board side and the exterior wall transition. This measurement will let you know how many soffit board widths there will be from the fascia to the eave.

  2. Calculate how many soffit board planks will be needed to fill the space from fascia to wall. If the calculations call for a final strip less than half the width of your soffit board-plank material, begin by ripping the first section down to split the difference; this will ensure you have enough soffit plank width on your final section to adjust for slight variances in the square framing of the building and patio roof structure.

  3. Begin at the patio-to-exterior-wall transition and work your way down toward the fascia. Cut the soffit board planks so the ends are aligned with the center of the patio trusses. Nail them to the trusses using the large-gauge finish nail gun. Be sure to stagger the butt seam joints or anywhere the end of one soffit board plank meets another. Separate these butt joints by at least one to two sections so that you will not have two consecutive butt joints on the same truss.