HVHZ Insulation Requirement for Flat Roof Replacement

[BuildingFlorida]

I am replacing an old, flat modified roof that has no insulation. The roof sits on a concrete slab. The project is in Broward County...a High Velocity Hurricane Zone. Can anyone tell me if the FBC requires that the new roof have insulation that meets the effective FBC code. If so, please provide a code section.

Thank You.

 

[RLGA]

A couple of questions:

1. Do you mean "modified" as in modified bitumen, or something else?
2. Are you sure the concrete is really not lightweight insulating concrete?

 

[BuildingFlorida]

Hello.
1. It's an old, modified bitumen roof.
2. It's a structural concrete slab. There is not lightweight insulating concrete.
Thank You.

 

[RLGA]

The following is from the 2020 FBC, Energy Conservation:

C501.7 Building systems and components.​

Thermal efficiency standards are set for the following building systems and components where new products are installed or replaced in existing buildings, and for which a permit must be obtained. New products shall meet the minimum efficiencies allowed by this code for the following systems and components:​

Heating, ventilating or air-conditioning systems;​

Service water or pool heating systems;​

Lighting systems; and​

Replacement fenestration.​

If the roof replacement is part of a building alteration, then the following applies:

C503.3 Building envelope.​

New building envelope assemblies that are part of the alteration shall comply with Sections C402.1 through C402.5.​

C503.3.1 Roof replacement.​

Roof replacements shall comply with Table C402.1.3 or C402.1.4 where the existing roof assembly is part of the building thermal envelope and contains insulation entirely above the roof deck.​

 

[steveray]

Typically required and ron gave you at least some of the sections

 

[BuildingFlorida]

The following is from the 2020 FBC, Energy Conservation:

C501.7 Building systems and components.​

Thermal efficiency standards are set for the following building systems and components where new products are installed or replaced in existing buildings, and for which a permit must be obtained. New products shall meet the minimum efficiencies allowed by this code for the following systems and components:​

Heating, ventilating or air-conditioning systems;​

Service water or pool heating systems;​

Lighting systems; and​

Replacement fenestration.​

If the roof replacement is part of a building alteration, then the following applies:

C503.3 Building envelope.​

New building envelope assemblies that are part of the alteration shall comply with Sections C402.1 through C402.5.​

C503.3.1 Roof replacement.​

Roof replacements shall comply with Table C402.1.3 or C402.1.4 where the existing roof assembly is part of the building thermal envelope and contains insulation entirely above the roof deck.​

THANK YOU!

 

[Paul Sweet]

Is there any provision for allowing a lesser R value than required for new construction, but no less than the existing R value if the increased thickness to meet the new R values would raise the roof above existing flashing or openings?

 

[steveray]

Is there any provision for allowing a lesser R value than required for new construction, but no less than the existing R value if the increased thickness to meet the new R values would raise the roof above existing flashing or openings?

Not really.....unless you use the God clause....

[A] 104.10 Modifications. Where there are practical difficulties
involved in carrying out the provisions of this code,
the building official shall have the authority to grant modifications
for individual cases, upon application of the owner or
the owner’s authorized agent, provided that the building official
shall first find that special individual reason makes the
strict letter of this code impractical, the modification is in
compliance with the intent and purpose of this code and that
such modification does not lessen health, accessibility, life
and fire safety or structural requirements. The details of
action granting modifications shall be recorded and entered
in the files of the department of building safety.

 

[jar546]

Not really.....unless you use the God clause....

[A] 104.10 Modifications. Where there are practical difficulties
involved in carrying out the provisions of this code,
the building official shall have the authority to grant modifications
for individual cases, upon application of the owner or
the owner’s authorized agent, provided that the building official
shall first find that special individual reason makes the
strict letter of this code impractical, the modification is in
compliance with the intent and purpose of this code and that
such modification does not lessen health, accessibility, life
and fire safety or structural requirements. The details of
action granting modifications shall be recorded and entered
in the files of the department of building safety.

Section 104.10 of Broward County, Florida