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Hurricane Irma

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Hurricane Mitigation

Retrofit Requirements and/or secondary waterproofing when an existing roof is replaced

Only site built single family residences are included in the requirement for mitigation retrofits and/or secondary waterproofing per Florida Statute 553.844, and only sloped hipped or gable roofs are required to comply. Townhouses and duplexes are not included under the definitions of site built single family residences and are therefore exempt from the mitigation requirements. Apartment buildings, condominiums, commercial building, and new construction roofs tied to a master building permit are also exempt.

On non-exempt structures that require mandated retrofits of the roof to wall connection, the maximum required dollar cost of these improvements per Florida Statute 553.844 shall not be required beyond a 15 per cent increase of the reroofing cost. Example: Replacement of the existing roof cost is $10,000.00 X 15% = $1,500.00 this amount is required to be spent on roof to wall connection retrofits.

Roof Sheathing

Roof sheathing shall be attached in compliance with the Florida Building Code, Florida Statue 553.844 and the Hurricane Mitigation Retrofit Manual. The Section 1524 Owner's Notification Form which is submitted in the High Velocity Hurricane Zone with the roof permit application, also references the requirement to refasten sheathing to meet current code requirements.

An Affidavit of Compliance for the Roof Decking Attachment and Secondary Water Barrier shall be provided to the Roofing Inspector at the time of first inspection. This affidavit shall be completed by the roofing permit holder.

Roof systems required to have secondary water barrier protection

Asphaltic shingle roofs, wood shingles or shakes, and architectural metal roof panels. These types of roof systems are considered discontinuous roof assemblies. (A discontinuous roof assembly consists of a roof system with unsealed overlapping components. These systems are typically applied to a sloped surface with a pitch of 2:12 or greater.

Cement or clay tile roof systems that have an approved tile underlayment system consisting of an ASTM # 30 basesheet with an ASTM # 90 capsheet or an approved base-sheet with a self-adhering polymer modified capsheet, shall be deemed to meet the requirements of a secondary water barrier.
Examples of a secondary water barrier as required when reroofing certain structures in the wind born debris region:

(1) Covering all joints of a plywood deck with a minimum 4" strip of self-adhering polymer modified bitumen tape, then followed by an approved basesheet installed over the modified bitumen tape and the roof deck.

(2) A #30 ASTM basesheet installed with nails and tin caps and covered with either an approved self-adhering polymer bitumen cap-sheet or an approved cap- sheet installed with hot asphalt.
In the High Velocity Hurricane Zone (HVHZ), full sheets of self adhering membranes can only be installed over a mechanically attached base sheet (the bottom or first ply of a roof assembly that has been mechanically attached to the sheathing).

The type of secondary water barrier that can be installed over a tongue and groove wood sheathing roof deck is 
an approved base sheet installed with nails and tin caps and covered with either a self-adhered polymer modified cap sheet or an approved capsheet using hot mopped asphalt may be installed over the basesheet. These types of applications are deemed to meet the requirements of a secondary water barrier.

Roof to wall connections

Only a licensed general, building, or residential contractor shall install the roof to wall connections retrofits. An "Affidavit of Compliance with Roof to Wall Connection" shall be provided to the Roofing Inspection at the time of the first Roofing Inspection. This affidavit shall be completed by the contractor.

Single family residences are exempt from the requirements of strengthening the roof to wall connections when replacing an existing roof as required by section 201.3 in the Hurricane Mitigation Manual, residences are exempt:
(1) When the just valuation for the structure for purposes of ad valorem taxation is less than $300,000.

(2) When the residence was constructed in compliance with the provisions of the Florida Building Code (FBC) or with the provisions of the 1994 edition of the South Florida Building Code (1994 SFBC).

Owners will complete and provide to the Roofing Inspector at the time of the first inspection the “Owner Affidavit of Exemption from Roof to Wall Connection Retrofit”  to demonstrate exemption from the requirements of section 201.3 in the Hurricane Mitigation Manual.

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Back to Top Page Last Edited: Wed Jan 25, 2017 11:57:29 AM

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