What Makes a Custom Home's Price per Square Foot Jump in St. Augustine? Finish Level, Metal Roof and Impact Windows

How finish level, a metal or tile roof and impact windows change a custom home's cost in St. Augustine, from published figures, and what Florida code requires.

Finish level, roof and impact windows affect the cost to build a 3,000 sq ft custom home on your St. Augustine lot. Wilson & Co Design Build points owners to published figures. 247Pro's Florida guide (July 2025) puts mid-range at $180 to $250 and luxury at $250 to over $300 per sq ft of house, lot excluded. This Old House (October 2026) lists installed architectural shingle at $7 per sq ft of roof and steel at $20 per sq ft of roof. Impact windows have no new-build price in our sources; windborne debris regions require protected windows, and impact glass is one of three ways.

On a St. Augustine custom home, your lot often decides more of the cost than the house does; see lot and county costs in St. Augustine.

How much more per square foot is a high-end finish than a basic one in St. Augustine?

A high-end finish on your St. Augustine custom home sits in a higher published price band than a basic one. For construction only, lot excluded, 247Pro's Florida guide (July 23, 2025) lists basic at $120 to $180 per sq ft and mid-range at $180 to $250 per sq ft. Luxury runs $250 to over $300 per sq ft on the same basis. On a 3,000 sq ft home, that is about $360,000 to $540,000 for basic and $540,000 to $750,000 for mid-range, by our arithmetic. Luxury comes to about $750,000 to $900,000 or more.

The tiers differ in what you see and touch every day: cabinets, counters, flooring, trim, plumbing fixtures, lighting and appliances. In the National Association of Home Builders' 2024 cost survey (published January 2025), interior finishes were 24.1% of construction cost nationally. That was the survey's largest single share.

You do not have to pick one tier for the whole house. You can spend on the kitchen and main bath and keep guest rooms at a mid-range finish. A production builder's starting price grows as you pick options; see how custom and production builders price a home.

Published prices for all three choices, each in its source's unit:

This Old House is the one roof source in the table.

How much more does a metal roof cost than shingles on a new home in Florida?

A steel roof on your new home in Florida costs about $13 more per sq ft of roof than architectural shingle, by our arithmetic from This Old House's figures. This Old House (updated October 2, 2026) lists installed architectural asphalt shingle at $7 per sq ft of roof. The same page lists an installed steel roof at $20 per sq ft of roof.

Metal roof prices spread widely. Your price depends on the metal, the panel style, and how many cuts and edges your roof has. Get a written price for the exact panel on your plans.

Roof prices are per sq ft of roof, and roof area is not your home's floor area. Your 3,000 sq ft home can have more or less than 3,000 sq ft of roof. A steep pitch, wide overhangs and covered porches add roof area, and a two-story plan needs less roof. Ask for a roof takeoff from your plans, then multiply your roof area by the price gap per sq ft of roof.

Does a tile roof change the framing on a new St. Augustine home?

A tile roof can change the framing on your new St. Augustine home because tile is heavy. This Old House (updated April 10, 2026) says a tile roof may need extra support. The same page lists installed clay tile at $8 to $22 per sq ft of roof and concrete tile at $7 to $19 per sq ft of roof. This Old House gives clay tile a life of up to 100 years and concrete tile up to 50 years.

Your engineer sizes the trusses or rafters for the tile product you pick. If you switch to tile after the trusses are designed, you may pay to redraw and reprice the roof framing.

Are impact windows required on a new St. Augustine home?

Protected windows are required on your new St. Augustine home if the lot sits in a windborne debris region, and impact glass is one way to meet that rule. The 2023 Florida Building Code, Residential, section R301.2.1.2, says glazed openings in those regions must be protected. Shutters or other coverings that pass the code's large missile test are another way to comply.

The 2023 code sets the region with the ASCE 7-22 wind maps. The windborne debris region covers land within 1 mile of the coast with open water upwind and a design wind speed of 130 mph or more. The region also covers any area with a design wind speed of 140 mph or more.

St. Johns County set up a windborne debris region by ordinance and points owners to an online wind speed lookup by parcel. Ask the county building official whether your lot is inside the region before you price windows.

If your lot is inside a windborne debris region, the Florida code accepts three ways to protect your windows:

1. Impact-rated windows and doors, with the protection built into the glass.
2. Shutters or other coverings that pass the large missile test.
3. Wood structural panels 7/16 inch thick, allowed only where the home's mean roof height is 33 feet or less and the design wind speed is 180 mph or less.

Bob Vila (updated June 9, 2023, crediting Angi and HomeAdvisor) lists impact windows at $100 to $2,100 per window. Labor runs $80 to $400 per window on the same page. Those are national 2023 figures, not new-construction prices, so get a window quote from your own plans. Before you buy, check your window's or shutter's Florida product approval at floridabuilding.org.

Does roof shape matter as much as roof material on a custom home?

Roof shape can move the price of your custom home as much as roof material does, because shape drives the framing. Your roof's geometry, span widths and ceiling heights drive framing and engineering more than square footage does, as Wilson & Co Design Build's custom home page puts it.

Each hip, valley and dormer adds cuts, framing and flashing, and long spans need bigger beams or engineered trusses. A simple roof costs you less to frame and cover, whether you pick shingle, metal or tile. A hip roof, which slopes down on all four sides, can also count for your insurance in Florida.

What does a wind mitigation inspection look at for Florida home insurance?

A Florida wind mitigation inspection records the parts of your home that resist wind. The inspector uses Florida's Uniform Mitigation Verification Inspection Form, OIR-B1-1802 (Rev. 04/26), in use since April 1, 2026. The form covers the building code, roof covering, roof deck attachment, roof-to-wall attachment, roof shape, secondary water resistance and opening protection.

Citizens Property Insurance lists wind mitigation discounts for opening protection, such as shutters and impact-resistant windows and doors, and for a hip roof shape. Citizens puts roof covering and roof deck attachment in a separate roof construction category. Citizens says these discounts apply only to the wind portion of your premium, and that the April 2026 form changes do not change its credits for now.

Other insurers set their own discounts, so ask your agent before you choose your roof or window protection.

Which upgrades should you decide before the plans are drawn?

Decide roof material, window protection and finish level before the plans for your St. Augustine custom home are drawn. Each one changes the drawings, the engineering or the budget, so a late change can mean paying for work twice.

1. Roof material and shape. Tile changes the framing, and shape changes the framing and maybe your insurance.
2. Window openings and wind protection. Impact glass, tested shutters or wood panels each change your window order and the details at each opening.
3. Finish level, room by room. The tier you pick sets the budget your design is drawn against.

Make your selections with the whole home in mind, and set your budget before design starts. Custom home design-build with Wilson & Co Design Build starts with your lot and sets finish level and budget before the plans. Wilson & Co Design Build is licensed and insured, Florida license CGC1534920. Call (904) 792-6175 to talk through your lot and your list of choices.

Questions owners ask about custom home upgrade costs

What affects the cost to build a custom home?

The cost to build a custom home in St. Augustine often depends more on your lot than on the house. After the lot, your finish level, roof material and shape, and window protection matter most. 247Pro's Florida guide (July 2025) puts construction alone, lot excluded, at $120 to over $300 per sq ft across its three finish tiers.

How much do custom home finish levels change the cost?

247Pro's Florida guide (July 2025, construction only, lot excluded) lists basic at $120 to $180, mid-range at $180 to $250 and luxury at $250 to over $300 per sq ft. On your 3,000 sq ft custom home, by our arithmetic, that is about $360,000 to $540,000, $540,000 to $750,000, or $750,000 to $900,000 or more.

How much more does a metal roof cost than shingles on a new home in Florida?

This Old House (updated October 2, 2026) lists installed architectural shingle at $7 per sq ft of roof and installed steel at $20 per sq ft of roof. By our arithmetic, steel costs about $13 more per sq ft of roof on a new home in Florida. Multiply that gap by your roof area from a takeoff of your plans, since roof area is not floor area.

What do lot clearing and fill add on a wooded Palm Coast lot?

Clearing and fill costs on a wooded Palm Coast lot depend on how many trees come out, how deep the fill must be, and the floor height flood rules require. No published figure for Palm Coast clearing and fill is given here. A coming article on Palm Coast lot clearing and fill covers that cost.

How much does a septic system add to a new home build?

No published septic price for a new home build is given in this article. A lot on St. Johns County sewer pays the St. Johns County Utility sewer connection fee of $6,106.03 instead (FY2027 rates, effective October 1, 2026). A septic system needs a state construction permit, so ask the county health department, and a coming article covers septic cost.

Is it cheaper to tear down and rebuild or remodel an older Ponte Vedra Beach house?

Whether a teardown or a remodel costs less on an older Ponte Vedra Beach house depends on the house you have. Where a home has good bones in the right location, Wilson & Co Design Build's custom home page says a renovation or addition usually gets there sooner and for less. A coming article covers the Ponte Vedra Beach teardown-or-remodel choice.