Sunroom bid calculator

How much to charge to build a sunroom

A published “$180 a square foot” special prices the floor. A residential sunroom is not a floor. It is glazed wall that does not scale with square feet, a thermal floor that may be an overlay or a new slab, an existing roof or a new insulated one, and often HVAC and a second slider. Matching the coupon on a 12×16 four-season room is how a sold job becomes a two-week loss after the first wall of glass.

The number a square-foot special cannot see

Take a 10×12 attached three-season on an existing deck, existing roof, vinyl windows, one slider. That is 32 lineal feet of wall and 256 square feet of glass — on a 120 square-foot floor. The coupon says $21,600. Raise the same shop to a 12×16 four-season. The floor is 192 square feet, so the coupon says $34,560. The glass did not scale that way: 40 lineal feet, insulated units, a new slab, an insulated roof, and often a mini-split the 10×12 never had.

Put four-season glass on that 12×16. Glass now costs more per square foot the vinyl 10×12 never priced. 10-foot walls are not “the same job plus two feet.” A second slider is not in the square-foot number at all.

How to price it

1. Measure width along the house and depth out from the wall.
2. Count glazed wall: three sides if attached, four if it wraps. Glass square feet is that perimeter times the glass height after the knee wall.
3. Add window units at your widths, knee-wall lineal feet when the job is not full-height glass, and floor or roof on the whole footprint when you are actually building them.
4. Price enclosure (three-season vinyl / four-season insulated), sliders, HVAC, electrical, and the permit allowance.
5. Load the wage, add materials and mobilization, mark overhead on direct cost, then divide by one minus the target margin. The walk-away price is total cost.

The sunroom bid calculator does that arithmetic in the browser from your own hours and invoices. Starting window widths, glass rates, and material rates are ballpark figures to replace, not a catalog or a code table.

What this is not

This is not a building-code opinion, a permit, a construction specification, or an engineering stamp. Confirm the jurisdiction and a qualified professional before sending a price. The output is arithmetic on the numbers you typed.

No warranty. This free article and calculator are not construction, legal, tax, financial, or engineering advice. To the maximum extent permitted by law, the authors accept no liability for loss or damage from their use. Hosted URLs, when they exist, may be taken offline without notice; there is no availability SLA.

Common questions

How much to charge to build a sunroom?

Start from the floor, count the glazed-wall square feet a square-foot special cannot see, then add the thermal floor, insulated roof, HVAC, electrical, and the permit. A published $180 per square foot special only sees width times depth.

Why do glass and a four-season enclosure change the price?

A 10-by-12 three-season on an existing deck is 32 lineal feet of wall and 256 square feet of vinyl glass on a 120 square-foot floor. A 12-by-16 four-season adds insulated glass, a new slab, an insulated roof, and often a mini-split. Matching the 10-by-12 coupon is how the four-season job loses money.

Is this a building-code calculation?

No. Window widths, spans, and glass rates here are common starting points on residential bids. They are not a building-code opinion, a permit, or an engineering stamp.