Cedar Shingle Coverage Calculator for Roofs & Walls

You feel a sense of dread, the kind that clenches your gut as you gaze at pile of cedar bundles in your driveway. What you read on the internet must of been right; you ordered up, but here you stand gazing at this wall with three window and a corner, and you’re thinking: Is it going to be enough? Cedar is gorgeous stuff, but man, if you were a little sloppy with your adding, she ain’t gonna forgive you.

And exposure. It all comes down to exposure realy, is the dividing line between what looks like a craftsman’s dreamscape…and something that look like a desperate patch job. It is a tiny thing, but it can be very important.

How to Count Your Cedar Shingles

The thing most folks count as “length” are actualy the shingle itself. Nope. The portion of a shingle that’s exposed to the elements is what matter. So if your shingles is 16-inches long but you only expose five inches of each, then you’ve got eleven inches covered by the next course up (and thus hidden from water). Good for you and good for your house, but it means that you’ll need far more shingles than there was square footage on your wall.

That’s why we do all that math for you; the calculator will take your bare-wall dimensions and convert it into how many actual field pieces, starter strips, etc., plus waste, you’ll need.

Deciding what size exposure to use is a matter of balance. On one hand, bigger is better because it is easier to lay out, uses less material per course, and looks nice and clean. But in areas where there is driving snow or really heavy rain, that big reveal isn’t necessarily safe. There is too much overlap so the water travels too far before it reaches the underlying row. A tighter exposure, something like four or five inches, protects the building better, but costs more money and take longer to install. You’re buying insurance with every additional inch.

If it’s a roof, not a wall, then you’ve got ridges and hips and valleys (more material). The app takes this into account. It lets you adjust the complexity factor, which adds a buffer based off how many caps and other diagonal cuts will ultimately need to be tossed into the trash can.

Cedar projects has one silent budget-killer: Waste. If you’re building a simple flat wall, maybe ten percent waste isn’t bad. However, if you add a steep pitch, complex corners, or dormers, things adds up quickly. You’ll cut shingles to fit around windows and, more often than not, those off-cuts won’t make their way back into the layout. Then there is sorting through the bundle to ensure colors match. You will set aside the discolored or knotty ones that do not fits the look. Those sorted pieces are still considered waste, even though structurally they’re perfectly sound.

It is better to err on the high side of this estimate rather than sit exposed waiting two weeks for a matching delivery of stock.

And then there’s the starter course. That one will throw your whole rhythm off if you forget to account for it, and it’s not something you should just begin laying down once you get to the bottom. Whether you use a specially cut starter strip or double up on rows at the eaves, you’ll want some kind of support for the first course. It is a little bit of material, but it is enough to mess up the rhythm of the wall if you forget it. The calculator breaks it out and lets you know exactly how many extra piece you’ll need for that first layer.

Round up. Always round up. Running out on a Friday afternoon hurts in a special way, and suppliers don’t usually sell half-bundles. Every manufacturer have different coverage per bundle, check the packaging for yours and be sure.

Take a breath and order. Yes, cedar will age beautifully, gray to a silvery color that conceals any small imperfections, but having a good estimate will leave you confident when you’re done; your house won’t look like it was scavenged, just seamless. That peace of mind is well worth the added math.