An existing building or portion thereof shall not be altered such that the building becomes less safe than its existing condition.
- All of Chapter 3, entitled "General Regulations," except Sections 303.7 and 306.
- All of Chapter 4, entitled "Gas Piping Installations," except Sections 401.8 and 402.3.
2.1. Sections 401.8 and 402.3 shall apply when the work being performed increases the load on the system such that the existing pipe does not meet the size required by code. Existing systems that are modified shall not require resizing as long as the load on the system is not increased and the system length is not increased even if the altered system does not meet code minimums.
3. All of Chapter 5, entitled "Chimneys and Vents."
4. All of Chapter 6, entitled "Specific Appliances."
Where alteration work includes replacement of equipment that is supported by the building or where a reroofing permit is required, the provisions of this section shall apply.
Where addition or replacement of roofing or replacement of equipment results in additional dead loads, structural components supporting such reroofing or equipment shall comply with the gravity load requirements of the Florida Building Code, Building.
- Structural elements where the additional dead load from the roofing or equipment does not increase the force in the element by more than 5 percent.
- Buildings constructed in accordance with the Florida Building Code, Residential or the conventional light-frame construction methods of the Florida Building Code, Building and where the dead load from the roofing or equipment is not increased by more than 5 percent.
- Addition of a second layer of roof covering weighing 3 pounds per square foot (0.1437 kN/m2) or less over an existing, single layer of roof covering.
- Opening protection exception. For one- and two-family dwellings constructed under codes other than the Florida Building Code and located in windborne debris regions, the replacement of garage doors and exterior doors with glazing, sliding glass doors, glass patio doors, skylights, and operable and inoperable windows within any 12-month period shall not be required to have opening protection but shall be designed for wind pressures for enclosed buildings, provided the aggregate area of the glazing in the replaced components does not exceed 25 percent of the aggregate area of the glazed openings in the dwelling or dwelling unit.
- Opening protection exception for High-Velocity Hurricane Zones. For one-and two-family dwellings constructed under codes prior to September 1, 1994, the replacement of exterior doors with glazing, sliding glass doors, glass patio doors, skylights, and operable and inoperable windows within any 12- month period shall not be required to have opening protection provided the aggregate area of the glazing in the replaced components does not exceed 25 percent of the aggregate area of the glazed openings in the dwelling or dwelling unit.
Openings in sunrooms, enclosed balconies and enclosed porches constructed under existing roofs or decks are not required to be protected, provided the space is separated from the building interior by a wall and all openings in the separating wall are protected in accordance with Section 1609.1.2 of the Florida Building Code, Building. Such spaces shall be permitted to be designed as enclosed or partially enclosed. (High-Velocity Hurricane Zones must comply with Chapter 16 of the Florida Building Code, Building.)
- Exterior balconies or porches under existing roofs or decks enclosed with screen or removable vinyl and acrylic panels complying with the Florida Building Code, Building, Section 2002.3.3 shall not be required to be protected and openings in the wall separating the unit from the balcony or porch shall not be required to be protected unless required by other provisions of this code.
- High-Velocity Hurricane Zones must comply with Chapter 16 of the Florida Building Code, Building.
Materials and methods of application used for recovering or replacing an existing roof covering shall comply with the requirements of Chapter 15 of the Florida Building Code, Building or Chapter 9 of the Florida Building Code, Residential. Roof repairs to existing roofs and roof coverings shall comply with the provisions of this code.
New roof coverings shall not be installed without first removing all existing layers of roof coverings where any of the following conditions occur:
- Where the existing roof or roof covering is water soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing.
- Where the existing roof covering is wood shake, slate, clay, cement or asbestos-cement tile.
- Where the existing roof has two or more applications of any type of roof covering.
- When blisters exist in any roofing, unless blisters are cut or scraped open and remaining materials secured down before applying additional roofing.
- Where the existing roof is to be used for attachment for a new roof system and compliance with the securement provisions of Section 1504.1 of the Florida Building Code, Building cannot be met.
- Building and structures located within the High-Velocity Hurricane Zone shall comply with the provisions of Sections 1512 through 1525 of the Florida Building Code, Building.
- Complete and separate roofing systems, such as standing-seam metal roof systems, that are designed to transmit the roof loads directly to the building's structural system and that do not rely on existing roofs and roof coverings for support, shall not require the removal of existing roof coverings.
- The application of a new protective coating over an existing spray polyurethane foam roofing system shall be permitted without tear-off of existing roof coverings.
- Roof Coating. Application of elastomeric and or maintenance coating systems over existing asphalt shingles shall be in accordance with the shingle manufacturer's approved installation instructions.
When a roof covering on an existing site-built single-family residential structure is removed and replaced, the following procedures shall be permitted to be performed by the roofing contractor:
(a) Roof-decking attachment shall be as required by Section 708.7.1.
(b) A secondary water barrier shall be provided as required by Section 708.7.2.
For roof decking consisting of wood structural panels, fasteners and spacing required in columns 3 and 4 of Table 708.7.1.2 are deemed to comply with the requirements of Section 706.3, Florida Building Code, Existing Building for the indicated design wind speed range. Wood structural panel connections retrofitted with a two part urethane based closed cell adhesive sprayed onto the joint between the sheathing and framing members are deemed to comply with the requirements of Section 706.3, Florida Building Code, Existing Building, provided testing using the manufacturer's recommended application on panels connected with 6d smooth shank nails at no more than a 6-inch (152.4 mm) edge and 12-inch (305 mm) field spacing demonstrate an uplift resistance of a minimum of 200 psf.
- 0.113-inch (2.9 mm) nominal shank diameter.
- Ring diameter a minimum of 0.010 inch (0.254 mm) over shank diameter.
- 16 to 20 rings per inch.
- A minimum 0.280-inch (0.7 mm) full round head diameter.
- Ring shank to extend a minimum of 11/2 inches (38 mm) from the tip of the nail.
- Minimum 23/8-inch (60 mm) nail length.
SUPPLEMENT FASTENERS AT PANEL EDGES AND
|Vasd 110 MPH OR|
SPACING SHALL BE
NO GREATER THAN
|Vasd GREATER THAN|
SHALL BE NO
|Staples or 6d||Any||6" o.c.b||6" o.c.b|
|None necessary||None necessary|
|6" o.c.a||6" o.c.a|
- Maximum spacing determined based on existing fasteners and supplemental fasteners.
- Maximum spacing determined based on supplemental fasteners only.
- Vasd shall be determined in accordance with Section 1609.3.1 of the Florida Building Code, Building or Section R301.2.1.3 of the Florida Building Code, Residential.
- In either HVHZ or Non-HVHZ regions:
- All joints in structural panel roof sheathing or decking shall be covered with a minimum 4-inch (102 mm) wide strip of self-adhering polymer modified bitumen tape applied directly to the sheathing or decking. The deck and self-adhering polymer modified bitumen tape shall be covered with one of the underlayment systems approved for the particular roof covering to be applied to the roof.
- The entire roof deck shall be covered with an approved asphalt impregnated 30# felt underlayment or approved synthetic underlayment installed with nails and tin-tabs in accordance with Section 1518.2, 1518.3 , or 1518.4 of the Florida Building Code, Building. (No additional underlayment shall be required over the top of this sheet.) The synthetic underlayment shall be fastened in accordance with the manufacturer's recommendations.
- Outside the HVHZ:
- The entire roof deck shall be covered with an approved self-adhering polymer modified bitumen sheet meeting ASTM D 1970 or an approved self-adhering synthetic underlayment installed in accordance with the manufacturer's installation instructions. No additional underlayment shall be required on top of this sheet for new installations.
- An underlayment system approved for the particular roof covering shall be applied with the following modification:
- For roof slopes that require one layer of underlayment, a layer of approved asphalt impregnated ASTM D 226 Type I or Type II, ASTM D 4869, Type II or Type IV underlayment or approved synthetic underlayment shall be installed. The felt is to be fastened with 1-inch (25 mm) round plastic cap, metal cap nails or nails and tin-tabs attached to a nailable deck with two staggered rows in the field of the sheet with a maximum fastener spacing of 12-inches (305 mm) o.c. and one row at the overlaps fastened 6-inches (152 mm) o.c. Synthetic underlayment shall be fastened in accordance with this section and the manufacturer's recommendations.
- For roof slopes that require two layers of underlayment, an approved asphalt impregnated ASTM D 226 Type I or Type II, ASTM D 4869, Type II or Type IV underlayment shall be installed in a shingle-fashion and lapped 19 inches (483 mm) and fastened with 1-inch (25 mm) round plastic cap, metal cap nails or nails and tin-tabs, attached to a nailable deck with one row in the field of the sheet with a maximum fastener spacing of 12-inches (305 mm), o.c. and one row at the overlaps fastened 6- inches (152 mm) o.c. An approved synthetic underlayment shall be installed in accordance with this section and the manufacturer's installation instruction. (No additional underlayment shall be required over the top of this sheet.)
- Roof slopes < 2:12 having a continuous roof system shall be deemed to comply with Section 708.7.2 requirements for a secondary water barrier.
- Clay and concrete tile roof systems installed as required by the Florida Building Code are deemed to comply with the requirements of Section 708.7.2 for secondary water barriers.
When a roof covering on an existing site-built single-family residential structure is removed and replaced on a building that is located in the wind-borne debris region as defined in the Florida Building Code, Building and that has an insured value of $300,000 or more or, if the building is uninsured or for which documentation of insured value is not presented, has a just valuation for the structure for purposes of ad valorem taxation of $300,000 or more:
(a) Roof to wall connections shall be improved as required by Section 708.8.1.
(b) Mandated retrofits of the roof-to-wall connection shall not be required beyond a 15-percent increase in the cost of reroofing.
Where required by Section 708.8, the intersection of roof framing with the wall below shall provide sufficient resistance to meet the uplift loads specified in Table 708.8.1, either because of existing conditions or through retrofit measures. As an alternative to an engineered design, the prescriptive retrofit solutions provided in Sections 708.8.1.1 through 708.8.1.7 shall be accepted as meeting the mandated roof-to-wall retrofit requirements.
- Where it can be demonstrated (by code adoption date documentation and permit issuance date) that roof-to-wall connections and/or roof-to-foundation continuous load path requirements were required at the time of original construction.
- Roof-to-wall connections shall not be required unless evaluation and installation of connections at gable ends or all corners can be completed for 15 percent of the cost of roof replacement.
REQUIRED UPLIFT CAPACITIES FOR ROOF-TO-WALL CONNECTIONSa, b (POUNDS PER LINEAR FOOT)
|ROOF SPAN (feet)||OVERHANGS|
|Within 6 feet of|
|Greater than 6|
feet from building
- The uplift loads are pounds per lineal foot of building length. For roof uplift connections multiply by 1.33 for framing spaced 16-inches on center and multiply by 2 for framing spaced 24-inches on center.
- The uplift loads do not account for the effects of overhangs. The magnitude of the above loads shall be increased by adding the overhang loads found in the table. The overhang loads are also based on framing spaced 12-inches on center. The overhang loads given shall be multiplied by the overhang projection and added to the roof uplift value in the table.
- For Ultimate design wind speeds, Vult, greater than 170 mph, wind uplift forces shall be determined in accordance with Florida Building Code, Residential, Section R802.2 or ASCE 7.
- Ultimate Design Wind Speeds determined from Figure 1609A in the Florida Building Code, Building or Figure R301.2(4) in the Florida Building Code, Residential.
These provisions are not intended to limit the means for gaining access to the structural elements of the roof and wall for the purposes of retrofitting the connection. The retrofit of roof to wall connections can be made by access through the area under the eave, from above through the roof, or from the interior of the house. Methods for above access include removal of roof panels or sections thereof or removal of portions of roof paneling at selected locations large enough for access, viewing, and installing the retrofit connectors and fasteners.
- Solid 11/2-inch lumber shall fully support the patch and shall be secured to the existing sheathing with #8 by 11/4-inch screws spaced a minimum of 3 inches (76 mm) around the perimeter with screws a minimum of 3/4 inch (19 mm) from the near edge of the hole. The patch shall be secured to the lumber with #8 × 11/4-inch screws spaced on a grid no greater than 6 inches by 6 inches (152 mm × 152 mm) with no fewer than two screws.
- Holes that extend horizontally from roof framing member to adjacent roofing framing member that are less than or equal to 7 inches (178 mm) wide along the slope of the roof shall be supported by minimum of 2 × 4 lumber whose face is attached to each roofing framing members using a minimum of two each 3-inch (76 mm) long fasteners (#8 screws or 10d common nails) connecting the two. The patch shall have attached to its bottom, running horizontally, a minimum 2 × 4 either flat wise or on edge secured with #8 × 11/4-inch screws a maximum of 4-inches (102 mm) on center and no more distant from the end of the added lumber than 3 inches (76 mm). The patch shall be secured with two #8 × 11/4-inch screws to each support member.