How to bid a siding job: measuring, pricing and the written quote

Measure each wall as width times height and add gables as half of base times height. One common approach is to deduct only large openings such as garage doors and picture windows and leave ordinary windows and doors in the area, on the reasoning that cutting around them produces offcuts anyway; some installers deduct every opening instead. Whichever rule you use, use it the same way on every bid so your rates stay comparable.

The calculator takes the total wall area, the number of stories, the material and a waste percentage between 5% and 15%. It adds the waste, rounds up to whole squares and prices the siding on the area with waste. Its default job is 1,800 sq ft of wall on a two-story house in vinyl with 10% waste: 1,980 sq ft of siding to buy, or 20 squares. The house size changes the takeoff like this:

Waste changes what you buy, not what you install. On the default job, 5% waste means 19 squares and $7,182 of material, 10% means 20 squares and $7,434, and 15% means 21 squares and $7,686. Labor stays at $6,300 in all three, because the calculator prices installation on the 1,800 sq ft of wall. A simple, boxy house can sit at the low end; a house with many corners, dormers and gables typically needs the high end.

Trim covers corners, J-channel around openings and similar accessories. The calculator estimates it at 0.15 linear feet per sq ft of wall for each story and prices it at $3.50 per linear foot. On the default wall area that is 270 feet ($945) for one story, 540 feet ($1,890) for two and 810 feet ($2,835) for three, giving totals of $12,789, $13,734 and $14,679. Treat that as a starting figure and count the real corners and openings on the walk-around.

Note what the stories setting does not do: it does not raise the labor rate. On a two- or three-story house, ladders, pump jacks or scaffolding and fall protection take time and equipment that a one-story job does not. OSHA notes that falls are among the most common causes of serious work-related injuries and deaths, so plan and price that setup as its own line rather than hoping the per-square rate absorbs it.

The calculator carries a material rate and a labor rate per sq ft for four sidings, plus the $3.50 trim rate. The table runs the same default job, 1,800 sq ft on two stories with 10% waste and trim, in each one. The per-square figure is the total divided by 18 squares of wall, which is how many contractors talk about price, and the last column applies 10% overhead and 20% profit.

Fiber cement and wood cost more on both lines, because the boards cost more and each piece takes longer to cut and fasten. If your crew is faster or slower on a given product, change the labor rate in the pricing section rather than adjusting the total by eye.

The calculator prices new siding, trim and installation. Everything below is outside it, and these are the lines that turn a profitable siding job into a break-even one when they are left off. Price each from your own costs and list it separately so the homeowner can see what it covers.

Lead deserves particular care. EPA's Renovation, Repair and Painting rule says anyone paid to perform work that disturbs paint in housing built before 1978 must be certified, and that this includes all firms, even sole proprietorships. Tearing off painted wood siding or trim on an older house is that kind of work, so check the build year before you bid and include the lead-safe setup, containment and cleanup in the price.

The siding calculator's estimate is your direct cost of material and labor. Switch the result panel to Contractor bid mode and it splits that cost into line items: siding, trim and accessories, and installation labor. Lines for trim or labor drop out when you untick those options. For the default vinyl job the lines are $5,544 of siding on 1,980 sq ft, $1,890 of trim on 540 linear feet and $6,300 of labor on 1,800 sq ft, which add up to the same $13,734. Bid mode then applies overhead first and profit on cost plus overhead. At its defaults of 10% and 20%, the job carries $1,373.40 of overhead and $3,021.48 of profit, for a customer price of $18,128.88, about $1,007 per square of wall.

Those two steps compound to a 32% markup over cost. That is not a 32% margin: as a share of the selling price it is about 24%. Mixing up markup and margin is an easy way for a bid to come in thinner than planned, so decide which one your books target and work back to the percentages. Bid mode also has a contingency percentage, applied before overhead, and a material tax percentage that applies to the siding and trim only. On the default job a 7% material tax adds $520.38 and brings the price to $18,649.26, and a 5% contingency on its own adds a $686.70 line before the markup and brings it to $19,035.32.

The extra lines from the previous section go in as bid mode extras, up to five, such as tear-off and disposal, sheathing allowance or lead-safe setup. They are added to the cost before the markup, so overhead and profit are earned on them too. A $1,800 tear-off line on the default job takes the price from $18,128.88 to $20,504.88.

A siding quote the homeowner can check heads off most disputes before they start. The FTC's advice to homeowners says a written estimate should include a description of the work, the materials, the completion date and the price, and that a contract should carry the contractor's name, address, phone number and license number with estimated start and completion dates. It also tells homeowners not to pay the full amount up front, and that a contract signed in their home should include a written statement of their right to cancel within three business days. Writing those items in from the start makes your quote easier to say yes to.

In Contractor bid mode the siding calculator prints a branded proposal with your company name, logo, phone, email and license number, the client and job address, the date and a valid-until date (30 days by default), the line items, the markup and the total. Use Print or Save PDF to send it, or copy a link that reopens the same bid. The scope, terms and cancellation notice are yours to add, so check that the siding quote you send covers these points: