How to Measure for Siding
Measure each wall section separately: length times height equals square footage. For gable ends, measure the rectangular portion and add the triangular peak (width times height divided by 2). Subtract windows (measure each individually) and doors. A standard entry door is about 20 sq ft. A typical double-hung window is 12-18 sq ft. A sliding patio door is about 40 sq ft. Sum all openings and subtract from the gross wall area. Add 10% waste for simple one-story homes or 15% for two-story homes with gables, dormers, and complex geometry.
Do not forget to measure the area inside roof gables, under soffits (if you want soffit material), and any other exterior surfaces that need covering. Most homeowners underestimate by focusing only on the main walls and forgetting the gable peaks, which can add 5-10% to the total. For the foundation below the siding line, you may need separate material (skirting or foundation coating). Use a paint calculator if you are painting existing siding instead of replacing it.
Siding Material Comparison
Vinyl siding is the most popular choice at $100-200 per square for materials and $350-600 installed. It is low maintenance, never needs painting, and comes in hundreds of colors. The downside is that it can crack on impact, fade over time, and warp if installed too tightly. Fiber cement siding (James Hardie, Allura) costs $150-300 per square for materials and $600-1,000 installed. It is fire-resistant, insect-proof, holds paint for 15 years, and can mimic wood grain realistically. It is the fastest-growing siding material for good reason.
Wood siding (cedar, redwood, pine) costs $200-400 per square for materials and $600-1,200 installed. It looks beautiful but requires painting or staining every 5-7 years and is susceptible to rot, insects, and fire. Engineered wood (LP SmartSide) costs $150-250 per square for materials and $500-800 installed. It offers the look of real wood with better durability and lower maintenance. Metal siding (steel or aluminum) runs $200-400 per square for materials and $600-1,200 installed, and is common in modern and industrial-style homes. For insulation upgrades during siding replacement, our insulation calculator helps plan the wall insulation.
Siding Installation Cost Breakdown
The total cost of a siding replacement project breaks down into several components. Tear-off and disposal of old siding: $1,000-3,000 depending on house size and number of layers. House wrap and weather barrier: $0.50-1.00 per sq ft ($500-1,500 for a typical home). Siding materials: varies by type, see above. Trim (corner posts, J-channel, starter strip, utility trim): $500-2,000. Labor: $200-400 per square for installation. Permits: $200-500. Dumpster rental: $300-600. Total installed cost for a 2,000 sq ft home: vinyl $7,000-12,000, fiber cement $12,000-20,000, wood $12,000-24,000.
Cost-saving tips: schedule your project in the off-season (late fall or winter in moderate climates) when contractors offer 10-20% discounts. Combine siding with a deck calculator to plan an outdoor living area alongside the exterior renovation. Do the tear-off yourself to save $1,000-3,000 in labor (but be prepared for a messy weekend). Buy materials directly from the supplier rather than through the contractor to save 10-15% on material costs. Check for utility rebates on insulated siding that can offset $500-1,500 of the cost.
Siding Installation Process
Step one is tear-off: remove all old siding down to the bare sheathing. Inspect the sheathing for rot, water damage, and structural issues. Replace any damaged areas with new plywood or OSB ($40-60 per 4x8 sheet). Step two is house wrap: install Tyvek or Typar over the entire exterior, lapping each course at least 6 inches over the one below. Tape all seams with manufacturer-approved tape. Install flashing around all windows, doors, and penetrations before the house wrap goes on.
Step three is trim installation: corner posts, J-channel around windows and doors, starter strip along the bottom, and utility trim at transitions. Step four is the siding itself, starting at the bottom and working up. Each course locks into the one below and is nailed at the nailing hem. Leave a 1/4 inch gap at all trim channels for thermal expansion. Stagger joints at least 24 inches between courses. Step five is finishing touches: install top coat or utility trim under the soffit, apply caulk where siding meets trim (but do not caulk the expansion gaps at J-channels). For a complete exterior renovation, coordinate with a fence calculator to include fencing in the project scope.
Common Siding Mistakes
Nailing siding too tightly is the most common installation error. Vinyl siding must float freely within the J-channel to expand and contract with temperature changes. Nails should be centered in the slot and driven to leave 1/32 inch (thickness of a dime) between the nail head and the siding. Driven too tight, the siding buckles on hot days. The second mistake is not lapping joints away from the street. All overlap joints should face away from the predominant view so the seam is less visible from the curb.
Forgetting to flash above windows and doors causes water infiltration behind the siding, leading to rot in the sheathing and framing. Always install Z-flashing above horizontal trim. Not installing house wrap is a building code violation in most jurisdictions and voids most siding warranties. Skipping the starter strip and starting the first course on the foundation means the bottom edge is not locked properly and will flap in the wind. Finally, mixing dye lots between walls creates a permanent color mismatch that is visible from across the street. Order all material at once from the same run.
For related calculations, try the concrete slab to estimate materials for your project.