Disclaimer and Safety Notes

General information only

LumberCalcs explains common guidelines and does the arithmetic for you. Every situation is different, and a result on this site can be wrong for yours, so please treat it as a starting point and not as an instruction. Always check important figures against the manufacturer's documentation, the applicable standard or a qualified professional. Use of this site is at your own risk.

Structure, spans and loads

The joist span, header, rafter and stair tools give simplified estimates. Real spans and loads depend on the species, grade, size, spacing, moisture, load and the span tables or engineering your local code requires. A structure that is too light or poorly connected can fail. For any load-bearing work, a deck, a roof, a beam or an opening in a bearing wall, use the building code's tables or a licensed engineer, and get the permits and inspections your area requires.

Building codes, permits and property lines

Codes cover deck height, guards, baluster spacing, stair dimensions, footings and fasteners, and they vary by place. A common requirement is that a guard's openings must not let a 4-inch sphere pass, but your area may differ. Fence height, setbacks, materials and property lines are set by local rules and sometimes by a homeowners association. Check the rules, and confirm the property line before you build.

Before you dig

In the United States, call 811 a few days before you dig, which is the free service that marks buried utility lines. Post holes, footings and trenches can strike gas, electric, water and communication lines, and hitting one is dangerous. The post depth and concrete tools do not know what is underground.

Treated lumber, fasteners and dust

Use fasteners and hardware rated for the treatment on pressure-treated lumber, because some chemicals corrode ordinary steel. Wear gloves and a dust mask or respirator when you cut or sand treated lumber, hardwoods such as ipe, MDF and other composite panels, and do not burn treated wood. Dispose of scraps as your local rules direct. Dense hardwoods need pre-drilled holes and suitable fasteners.

Tools, ladders and falls

Saws, nailers and routers cause serious injuries. Read the tool's instructions, use eye and hearing protection and keep guards in place. Decks, ladders and roofs carry a risk of falls, so use stable ladders and fall protection where it is needed and do not work alone at height.

Wood varies

Wood is a natural material. Actual dimensions, moisture content, hardness, weight and movement differ between boards and suppliers, and species and grade names are not always used consistently. Treat counts and quantities as estimates, add an allowance for waste and check the stamps and tags on the lumber you buy.

Prices, quizzes and links

Prices and cost figures are typical examples that vary by region, brand and time. The finders choose from a short list of options based on a few answers, and they cannot see your situation or recommend a particular brand or product. Links to other websites are provided for convenience, and we are not responsible for their content. To report an error, use the Report an Issue form. LumberCalcs is independent and is not affiliated with any manufacturer, retailer or organization.