How to Measure For New Siding

Posted on July 25, 2017 within Pros Who Know

Measuring for new siding is critical to accurately quoting a job. PFT Installation expert Jared explains how to correctly measure a home for new siding, using our Estimate Worksheet to help make the process easier.

Measuring Walls

Start with all square and rectangular walls, measuring height and width. Siding is ordered in “squares”. One square equals 100 square feet, so multiply height x width, then divide by 100 for total “squares”.

If you are using different materials on different walls, you will want to keep these separate. Do not subtract window area, unless there is a very large picture window. You will subtract the garage door area.

Measuring Gables

When measuring gables, measure height and width, then multiply by .75.

If a gable is hard to reach, measure the height of the current siding profile, then multiply by the number of courses on the wall section. For dormers, take width by height by 1.5. This gives you enough material for both sides.

Calculating Accessories

Corner Posts: Avoid seams in corner posts when possible and plan on one full post per corner.

Starter Strip: For starter strip and starter adapter insulation, measure the base of all walls. If the siding meets brick, you will also need Z-flashing here. You do not need a starter strip if the wall meets at a deck, you will use j-channel here.

J-Channel: For all other j-channel, plan on 2 pieces per window, and one-and-a-half pieces for each regular size door. You also need j-channel where the tops of the walls meet the soffit.

Above Windows & Doors: Measure the top of each window & door for drip caps. If undersill trim is required, simply use the same measurement as for drip cap.