Polk County doesn’t have a single countywide yes-or-no answer. The Florida Building Code defines the wind borne debris region with two tests. Inland locations turn on whether the applicable ultimate design wind speed reaches 140 mph. In our state-data measurement, every Polk County city point checked sits between the 130 and 140 mph contours for Risk Category II. The approved permit package controls for a specific address.
What is the wind-borne debris region?
The wind-borne debris region is a two-part code test. The definition begins with “Areas within hurricane-prone regions located:”.
The first condition is “Within 1 mile (1.61 km) of the coastal mean high water line where the ultimate design wind speed, Vult, is 130 mph (58 m/s) or greater; or”.
The second condition is “In areas where the ultimate design wind speed, Vult, is 140 mph (63.6 m/s) or greater.”
The first condition combines coastal proximity with wind speed. The second applies wherever the applicable speed reaches 140 mph. That second condition is the important branch for inland Polk County.
The code also identifies which map governs the test. It states, “For Risk Category II buildings and other structures and Risk Category III buildings and other structures, except health care facilities, the wind-borne debris region shall be based on Figure 1609.3(1).”
So the risk category picks the map, and the map decides the test. Land inside the region and your glazed openings have to be impact resistant or covered, subject to the exceptions further down.
Why the answer for Polk County depends on a contour line
A county name alone can’t settle this. The code hands the exact placement of those lines to local government.
Section 1609.3 states, “The exact location of wind speed lines shall be established by local ordinance using recognized physical landmarks such as major roads, canals, rivers and lake shores wherever possible.”
The Florida Building Commission’s adopted wind-zone contour data is available through the University of Florida GeoPlan Center. We measured every Polk County place in our service area against that published dataset.
On the Risk Category II layer, the nearest 140 mph contour lies seaward. The nearest 130 mph contour lies inland. Lakeland, Bartow, Winter Haven, Auburndale, Haines City, Davenport, Lake Wales and Frostproof sit between those contours in our measurement.
Lakeland measured 23.9 miles from the 140 mph contour. Bartow measured 22.9 miles away. Winter Haven and Davenport each measured 33.7 miles away. Frostproof measured 26.9 miles away.
Those distances don’t establish a design speed or debris-region status for any address. The dataset’s own reading instructions say, “Mapped wind speed contour lines delineate wind speed increments of either 5 mph or 10 mph and are not intended to represent a zone’s fixed wind speed. Linear interpolation of wind speed between contour lines is permitted.”
The approved permit package remains the address-specific authority. Our guide to wind load and engineering for a Polk County enclosure covers what belongs in that package.
The 110 mph map the state still publishes
The Polk County map on the state’s Wind Maps by County page dates from 2007. Its legend reads “Basic Wind Speed Line, Figure 1609, FBC June 2007.”, “Source: Polk County Building Division”, “All of Polk County is in the 110 MPH Wind Zone.”, and “(Confirmed by Polk County Building Division 06/04/07)”.
That map presents a basic wind speed under a superseded code. Today’s code uses ultimate design wind speed. They are different quantities, and the old figure shouldn’t be converted or published as a current value.
A bid or forum post quoting 110 mph for Polk County is quoting a 19-year-old map. It isn’t identifying the current design value for a project.
Your pool cage and your house are not in the same risk category
The Florida Building Code names screen enclosures under Risk Category I. That matters because Risk Categories I and II use different wind maps.
Table 1604.5 describes Risk Category I as “Buildings and other structures that represent a low hazard to human life in the event of failure, including but not limited to:”.
Its listed examples include “Agricultural facilities.”, “Certain temporary facilities.”, “Minor storage facilities.”, and “Screen enclosures.”
Risk Category II covers “Buildings and other structures except those listed in Risk Categories I, III and IV.”
Section 1609.3 then assigns separate figures. It states, “The ultimate design wind speed, Vult, for use in the design of Risk Category II buildings and structures shall be obtained from Figure 1609.3(1).”
For Risk Category I, it states, “The ultimate design wind speed, Vult, for use in the design of Risk Category I buildings and structures shall be obtained from Figure 1609.3(4).”
That is why a cage and house on the same lot use different wind-speed values. The structure’s category determines the applicable map.
Our measurement against the Risk Category I layer placed the same service-area points between the 120 and 130 mph contours. That’s our contour measurement, not a published value for any address. Linear interpolation remains permitted, and local ordinance establishes exact line locations.
Table 1604.5 names screen enclosures only. It says nothing about a glazed sunroom, three-season room or carport. We make no claim about those structures’ risk categories.
If you’re weighing a cage against a screen room, our pool cage and screen room pages lay out what each one is. Our Lakeland outdoor living service area page covers the rest of the county we reach.
How a screen enclosure is actually designed for wind
A cage follows a different code path than the house it attaches to. There’s no glazing in a screen wall, so the debris-region question never lands on it the same way.
Section 1609.1.1 states, “Wind loads for screen enclosures shall be determined in accordance with Section 2002.4.”
Section 2002.4 explains, “Structural members supporting screened enclosures shall be designed for wind in both of two orthogonal directions using the pressures given in Table 2002.4.”
It also requires another load check: “Each primary member shall also be designed for a 300 pound (1.33 kN) load applied vertically downward along any 1 foot (305 mm) of any member, not occurring simultaneously with wind load.”
The table publishes horizontal windward pressures for several conditions. At Exposure B, they are 23 psf at 130 mph and 27 psf at 140 mph. At Exposure C, they are 32 psf and 38 psf at those speeds.
Exposure category describes the surrounding terrain used in the pressure calculation. These figures are published code-table values. They aren’t the design pressure for any particular project.
Section 2002.4.1 adds, “The AAF Guide to Aluminum Construction in High Wind Areas shall be accepted as conforming to accepted engineering practices.”
Your engineer of record picks the right criteria for the actual cage. The approved plans are where that work gets written down.
Does a sunroom need impact glass in Polk County?
Not automatically. The code includes an exception for certain spaces under existing roofs, but the separating-wall condition matters.
Section 1609.1.2 begins, “In wind-borne debris regions, glazed openings in buildings shall be impact resistant or protected with an impact-resistant covering”.
It then provides this exception: “Openings in sunrooms, balconies or enclosed porches constructed under existing roofs or decks are not required to be protected provided the spaces are separated from the building interior by a wall and all openings in the separating wall are protected in accordance with Section 1609.1.2 above.”
The next sentence adds, “Such spaces shall be permitted to be designed as either partially enclosed or enclosed structures.”
In plain language, the wall between the new room and house must remain. The openings in that separating wall carry the protection requirement. Removing that wall to open the room into the house changes the code question.
Our sunroom page walks through what that build involves. If you’re closing in a lanai the builder already roofed, read screening in a builder-covered lanai too.
For the local permit path, see our guide to sunroom permits in Polk County. The permit desk and engineer of record can address a specific property.
Wind Zone 1 on a label is not a design wind speed
A product’s Wind Zone number identifies an impact-test zone. It doesn’t state the structure’s design wind speed.
Section 1609.1.2.2 sets those zones out as ranges. Wind Zone 1 runs from 130 mph up to but not including 140 mph. Wind Zone 2 runs from 140 mph up to but not including 150 mph, and only at greater than one mile from the coastline, which the code measures “from the mean high water mark.”
Those are ASTM E1996 test zones the Florida Building Code substitutes in. A Wind Zone number tells you which impact test a product passed. It doesn’t tell you what your structure was designed to carry.
So both numbers can turn up in one conversation and mean completely different things. The label answers a product question. The approved plans answer the structural one.
Frequently asked questions
Is Polk County in the wind-borne debris region?
Polk County doesn’t have one countywide answer. For an inland location, the test turns on whether the applicable ultimate design wind speed reaches 140 mph. Our measured city points fall between the 130 and 140 mph contours, but the permit package controls for each address.
Do I need impact glass for a sunroom in Lakeland?
Impact glass isn’t automatically required for every Lakeland sunroom. The code provides an exception under an existing roof when a wall separates the room from the house and openings in that wall are protected. The permit package decides the requirement for your address.
What wind speed is a Polk County pool cage designed for?
There isn’t one pool cage design speed for Polk County. The code lists screen enclosures as Risk Category I and routes their wind loads to Section 2002.4. The engineer of record and approved permit package establish the design criteria for a specific cage.
Is a screen enclosure a different risk category than my house?
Yes. The code lists screen enclosures in Risk Category I, while buildings outside Categories I, III and IV fall under Risk Category II. That difference sends the cage and house to separate wind maps, but the table doesn’t classify sunrooms, three-season rooms or carports.
Why does the state’s Polk County wind map say 110 mph?
The state’s Polk County page still serves a map labeled “Basic Wind Speed Line, Figure 1609, FBC June 2007.” Its 110 mph statement belongs to that superseded code map. It isn’t a current ultimate design wind speed and shouldn’t be used that way.
Get the right answer for your enclosure
Start with the approved plans for the actual address. Our guides cover screen enclosure permits in Polk County and wind load and engineering without replacing the permit desk or engineer of record.
We connect homeowners with insured local aluminum crews. We don’t perform licensed work or provide engineering opinions. Call (863) 777-5379 to discuss your enclosure and get matched with a local crew.