Furring Strip Spacing Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/7/2026
The number of furring strips needed is calculated by dividing the length to cover by the spacing (center-to-center distance), then adding 1 for the starting strip. For a 5 m wall with a 40 cm spacing, you need 14 strips.
Explanation
Installing a frame of furring strips (for cladding, drywall, or paneling) at regular intervals is a classic case of the "fence post" problem: the number of strips needed isn't simply the length divided by the spacing, but that result plus one extra strip. The reason is geometric: to cover a length with equal intervals, you need a strip at each end of the length, plus the strips in between — a wall with 3 intervals of 40 cm (120 cm total) therefore needs 4 strips (at positions 0, 40, 80, and 120 cm), not 3. Forgetting this "+1" is a common mistake that leads to underestimating the number of strips by one, a gap that may seem minor but leaves the final interval too wide if the error isn't caught in time. The most common spacing (the center-to-center distance between two consecutive strips) is 40 or 60 cm for a drywall or cladding frame, the exact value depending on the product installed on top (drywall or cladding manufacturers generally specify the maximum recommended spacing for their product, which shouldn't be exceeded to ensure adequate fastening). Once the frame is installed and clad, our paint quantity calculator helps estimate the paint needed for the finish; for a floor frame rather than a wall one, see instead our flooring quantity calculator.
Example: a 5 m wall, 40 cm spacing
Inputs
Length to cover: 5 m. Spacing: 40 cm.
Calculation
Number of intervals = 500 ÷ 40 = 12.5, rounded up to 13. Number of strips = 13 + 1 = 14.
Result
This frame needs 14 furring strips.
Frequently asked questions
Why do you add 1 to the division result, rather than just rounding?
Because the number of strips corresponds to the number of interval endpoints, not the number of intervals itself: dividing the length by the spacing gives the number of intervals, but each interval shares two endpoints with its neighboring interval, except at the two ends of the wall. You therefore always need one more strip than the number of intervals to properly cover both ends of the total length.
What spacing should I choose depending on the product fastened on top?
The recommended spacing depends on the product installed on the frame and its weight: 40 cm is common for standard drywall, while heavier exterior cladding or a support that must withstand greater loads (wind, self-weight) may require a tighter spacing. Always check the product's technical data sheet for the maximum recommended spacing, which shouldn't be exceeded.
Does this calculation give an exactly even spacing over the whole length?
The calculation rounds the number of intervals up to the next whole number when the length doesn't divide evenly by the chosen spacing, which means the actual final spacing may be very slightly smaller than the targeted spacing (to stay even over the whole length), rather than leaving one last interval wider than the others.