Project guides
How deep, how thick, how much. Each guide names its sources, works through an example and links to a calculator for your own numbers.
8 guides
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Roofing and stairs How many bundles of shingles per square: 3 for most, up to 6 Most 3-tab and architectural shingles take 3 bundles per 100 sq ft square. Some designer and shake styles take 4, 5 or 6. Maker data checked October 14, 2026. -
Decks, fences and patios How deep should deck footings be? Find your frost depth Below your local frost line and at least 12 in down. In the places we checked, depths ran from 24 in in northern Virginia to 60 in in northern Minnesota. -
Decks, fences and patios How tall can a retaining wall be without an engineer? Over 4 ft of soil, or over 2 ft with a load like a driveway above, the model code requires an engineered wall. Block makers often stop sooner. -
Concrete How cold is too cold to pour concrete? Rules for a fall pour Fresh concrete has to reach 500 psi before it freezes, about two days at 50°F. When to pour, when to cover it, and when to wait until spring. -
Decks, fences and patios How deep should fence posts be? (And how much concrete) For a 6 ft fence, bury posts 2 to 3 ft deep plus 6 in of gravel, and go below the frost line where the ground freezes. Bags of concrete per post, by depth. -
Yard, garden and pool How deep should mulch be? (And how many bags to buy) 2 to 4 inches of mulch, kept off tree trunks. How much to buy, how to top up an old layer without going too deep, and a coverage chart per cubic yard. -
Yard, garden and pool How much gravel do you need for a driveway or patio base? Base depths for gravel driveways, paver patios and concrete slabs, why you order 25% more than the finished depth, and a worked 12 x 50 driveway in tons. -
Concrete How thick should a concrete patio be? 4 inches for foot traffic and a grill, 5 to 6 inches under a hot tub. Plus the base, joints and slope that decide whether the patio cracks.