From the Roof Down: Planning a Whole-House Exterior With Numbers That Work
Roofing, pitch, fencing, and decking share one secret: they're all area-and-waste problems dressed up as different trades. Here's how to plan the entire exterior in one sitting.
The Exterior Is One Big Area Problem
Most homeowners think of a roof, a fence, and a deck as completely different projects. They're not. Each one boils down to the same question: how much area am I covering, and how much waste do I add? Once you see the pattern, you can plan an entire exterior renovation in a single afternoon — with numbers your contractor will respect.
Start at the Top: Roofing Squares
Roofing is sold in "squares" — one square covers 100 sq ft. A 1,800 sq ft single-story house with a moderate pitch needs roughly 20–22 squares of shingles, plus underlayment, drip edge, and nails. The mistake almost everyone makes is forgetting the waste factor: hips, valleys, and cuts eat 10–15%.
The Roofing Square Calculator takes your roof dimensions, applies the waste factor, and spits out squares, bundle counts, underlayment rolls, and nail boxes — all tied to your local material prices.
Know Your Pitch Before You Buy Anything
Pitch changes everything. A 12/12 pitch roof has nearly 1.5× the surface area of a flat roof over the same footprint, which means 50% more shingles. Before you call a roofer for a quote, run your rise and run through the Roof Pitch Calculator. You'll get the pitch ratio, the degree angle, the percentage slope, and the rafter length — so when the contractor says "it's a 6/12," you'll know exactly what that means for your budget.
Work Down to the Fence Line
A new fence is the most common weekend warrior project — and the most commonly mis-estimated. A 150-foot cedar privacy fence isn't just 150 feet of boards. It's posts every 8 feet (19 posts), 3 rails per section, 114 pickets at 6-inch spacing, and 19 bags of post concrete. Miss the concrete and you're making a second trip before the first hole is dug.
The Fence Material Calculator breaks the whole bill of materials down — posts, rails, pickets, concrete, and gate hardware — from your linear footage, spacing, and height.
Finish With the Deck
Decks are where "I'll just buy extra" gets expensive fast. A 12×16 deck needs about 200 linear feet of 5/4 boards, 10 joists, 6 posts, and a hardware bag — and composite boards with hidden fasteners waste differently than wood with face screws.
The Deck Board Calculator accounts for board spacing, waste, and material type, then multiplies by your local price per board foot so you know the number before you walk into the lumber yard.
Do It All in One Pass
Here's the part most calculators miss: you can save every result. Create a free BuildPlan account, run the roof, the fence, and the deck, and save each calculation with a project name like "2026 Exterior Refresh." Then print the whole set and hand it to your contractor — or use it to compare quotes apples-to-apples.
When every number on the page came from the same tool, you can trust that the totals are consistent. That's the difference between a plan and a wish.
The Exterior, Planned
You don't need a general contractor to build a materials list — you need the right formulas and your local prices. Start at BuildPlan, work from the roof down, and turn your exterior wish list into a shopping list.