SECTION 13145
(13 34 21)
RETROFIT STEEL
SUB-PURLINS
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Specifier Notes: This section covers “Roof Hugger”
sub-purlins for retrofitting roofs, walls, and fascias over existing rib
metal panels. The one-piece,
custom-punched, galvanized steel, Z-section fits into and over existing
profile to be covered. The
sub-purlins are prepunched to nest into the existing rib profiles,
prepunched for fasteners, and fasten directly into the existing purlins with
fasteners.
The new International
Building code adopted by all U.S. states requires the roofs to be analyzed
by zones IE: corner, edge and field zones.
Each zone will have a different uplift load requirement. Older buildings were designed with
uniform roof loading as a result the 5’ purlin spacing typically found in older
buildings may not be adequate meet current code requirements in high wind zone
areas. The new sub-purlin type and
spacing will be a function of the uplift loads, the type of existing panel,
and the type and gauge of the new roof panel specified. Roof Hugger recommends consulting a
qualified design professional to determine the loads, a compliant roof panel
and the proper sub-frame spacing.
Retrofitting an existing
roof will create a cavity between the new and existing roofs. Consideration for ventilating and/or
insulating this cavity must be given.
Consult Roof Hugger, if needed, for assistance in editing this
section for the specific application.
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PART 1 GENERAL
1.1 SECTION INCLUDES
A. Retrofit steel
sub-purlins.
1.2 RELATED SECTIONS
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Specifier Notes: Edit the
following list of related sections as required for the project. List other sections with work directly
related to this section.
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A. Section 05400
(05 40 00) - Cold-Formed Metal Framing.
B. Section 07220
(07 22 00) - Roof and Deck Insulation.
C. Section 07400
(07 40 00) - Roofing and Siding Panels.
D. Section 07720
(07 72 00) - Roof Accessories.
E. Section 13120
(13 34 19) - Pre-Engineered Structures (Metal Building Systems).
1.3 REFERENCES
A. ASTM A 653/A
653M - Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or
Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process.
B. ASTM A 1011/A
1011M - Standard Specification for Steel, Sheet and Strip, Hot-Rolled, Carbon,
Structural, High-Strength Low-Alloy and High-Strength Low-Alloy with Improved
Formability.
1.4 SUBMITTALS
A. Comply with
Section 01330 (01 33 00) - Submittal Procedures.
B. Product
Data: Submit manufacturer's product
data, including installation instructions.
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Specifier Notes: Edit the
following paragraph regarding shop drawings as required for the
project. Sub-purlins are typically
produced 3/8 inch to 1 inch taller than the height of the major ribs of the
existing roof panels. Indicate on
the shop drawings if a specific sub-purlin height is required.
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C. Shop
Drawings: Submit manufacturer's shop
drawings for sub-purlins indicating gage, yield strength, flange and web sizes,
cutout dimensions, and punch pattern for attachment holes in base flange.
D. Design
Data: Submit design data from
independent engineering firm indicating table of wind uplift capacity of sub-purlins.
1.5 DELIVERY, STORAGE, AND HANDLING
A. Delivery: Deliver materials to site in manufacturer's
original, unopened bundles, containers, and packaging, with labels clearly
identifying product name and manufacturer.
B. Storage:
1. Store materials in accordance with
manufacturer's instructions.
2. Protect sub-purlins from corrosion,
deformation, and other damage.
3. Store sub-purlins off ground, with 1 end
elevated to provide drainage.
C. Handling: Protect materials during handling and
installation from corrosion, deformation, and other damage.
PART 2 PRODUCTS
2.1 MANUFACTURER
A. Roof Hugger,
Inc., PO Box 1027, Odessa, Florida 33556.
Toll Free Phone (800) 771-1711.
Toll Free Fax (877) 202-2254.
Phone (813) 909-4424. Fax (813)
909-4511. Website
www.roofhugger.com. E-Mail
dale@roofhugger.com.
2.2 RETROFIT STEEL SUB-PURLINS
A. Retrofit
Sub-Purlins: “Roof Hugger”.
1. Description:
a. 1-piece, custom-punched, Z-section.
b. Prepunched to nest into existing rib
profiles.
c. Prepunched for fasteners.
d. Fastens directly into existing purlins
with fasteners.
2. Material:
Galvanized steel, ASTM A 653 or A 1011, G-90, yield strength 50 ksi.
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Specifier Notes: Specify
gauge. 16 gauge is standard. Consult Roof Hugger for other gauges,
including engineering values and lead time.
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3. Thickness:
[16] [14] [ ______ ] gauge.
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Specifier Notes:
Sub-purlins are typically produced 3/8 inch to 1 inch taller than the
height of the major ribs of the existing roof panels. Consult Roof Hugger for cost-efficient
sizes to meet project requirements if web height other than manufacturer's
standard is needed.
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4. Web Height:
[ ______ inches] [manufacturer's
standard].
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Specifier Notes: The
number of holes provided in the base flange will be greater than or equal to
the required number of fasteners to be installed per linear foot. Custom hole punching of the base flange
is available upon request. Roof
Hugger may punch additional unused holes in the base flange to aid in
installation or to minimize conflict with existing fasteners.
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B. Base
Flange: Prepunch base flange to
manufacturer's standard.
C. Fasteners:
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Specifier Notes: The following fasteners are typical
minimum for attachment of new sub-purlins to existing metal building
purlins. Fastener length will vary
with thickness of existing insulation.
Fastener length of 1-1/4 to 1-1/2 inches is typical.
Attachment of sub-purlins to existing structural steel (i.e. bar
joist/structural channels) will require appropriate fasteners. Roof Hugger does not supply
fasteners. Consult Roof Hugger for
additional information regarding fasteners.
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1. Attachment to Existing Purlins: #12-14 threads per inch, self-drilling,
Tek-3.
a. Length:
Required to penetrate existing purlins in accordance with fastener attachment
standards.
2. Sub-Purlins Installed Mid-Span: #12-14
threads per inch, self-drilling, Tek-3 fasteners or equal into sub-rafter
structure, #17-14 into existing panel when indicated and #10 pancake head through Hugger top flange into
sub-rafter when indicated.
PART 3 EXECUTION
3.1 EXAMINATION
A. Examine
areas to receive sub-purlins. Notify
Architect if areas are not acceptable.
Do not begin installation until unacceptable conditions have been
corrected.
B. Verify
existing purlins and eave struts are in good serviceable condition, without
rust-thru of flanges.
C. Field Verify
Before Installation of Sub-Purlins:
1. Existing panel profile and panel rib
dimensions.
2. Existing panel run-out by measuring roof over
several 20-foot areas to confirm panels were installed on module and
in-square. Note variations.
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Specifier Notes: Indicate
on the Drawings details of the major and minor rib configurations of the
existing roof panels. If the
existing roof is standing seam, verify whether thermal blocking has been
installed. If thermal blocking
exists consult Roof Hugger, Inc. regarding this situation because special
details and parts may be required for this type of panel. Roof Hugger existing panel details are
available to aid in obtaining this information. Refer to www.roofhugger.com/roof_details.html, details 17, 18,
19, and 20.
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3.2 INSTALLATION
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Specifier Notes: Consult
Roof Hugger for information regarding the installation of sub-purlins for
special situations.
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A. Install
sub-purlins in accordance with manufacturer's instructions at locations
indicated on the standard details or Engineered Drawings if provided.
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Specifier Notes: The existing roof is not weathertight
until new roof panels are installed over the sub-purlins. Installation of sub-purlins may need to
be limited to the amount that can be roofed over each day. Consult Roof Hugger to discuss other
options to minimize weather issues.
Edit the following paragraph as required.
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B. Limit
installation of sub-purlins to amount that can be roofed over each day.
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Specifier Notes: Specify
number of fasteners (typically less than or equal to the number of holes
specified in paragraph 2.2.B) required to be installed per linear foot, as
determined by wind load criteria.
Typically 2 fasteners per linear foot are required. Refer to Roof Hugger engineering data for
allowable uplift loads. Edge zones
and field can be specified separately if desired.
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C. Install
[1] [2] [3] fasteners per linear foot.
D. Install
sub-purlins directly over existing purlins and fasten to existing purlin
through existing panel pan section.
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Specifier Notes: In high-wind zones, special fitted sub-rafters
may be required to allow for the installation of Huggers mid-span between
existing purlins. Grids made of “Cee’s”,
“Zee’s”, and/or “hats” may be specified in lieu of special fitted
sub-rafters in the corner and/or edge areas to meet the load
requirements. The selection of the
fitted sub-rafter, or grid system is a function of existing roof panel, the
new roof panel and the corner, edge and field pressures. A preliminary estimate of the roof zone
pressures can be made at http://www.roofwinddesigner.com/
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E. Install Sub-rafters between the existing purlins with #12/14
threads per inch, T-3 fasteners into the existing purlins. Sub-rafter spacing and number of fasteners
shall be as specified on the engineered drawings or as specified in the Roof
Hugger, Florida Product Approval.
F.
Install Huggers over
the sub-rafters in areas where they are specified and into the existing purlins
being careful to maintain the alignment of the sub-rafters.
G.
Install Huggers onto
the sub-rafters between the existing purlins as specified with #12/14 threads
per inch, T-3 fasteners, typically one fastener on each side of the sub-rafter
unless otherwise specified.
H.
Where the Roof Hugger
is attached to the existing roof panel the hole should be drilled out to the
correct diameter to allow for the installation of a #17 fastener through the
Roof Hugger and into the existing roof panel.
I.
Where the Roof Hugger
passes over the fitted sub-rafter a #10 pancake head fastener should be
installed through the top flange of the Roof Hugger into the top of the new
fitted sub-rafter.
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Specifier Notes: Removal of Existing Roof Fasteners: Typically,
the existing roof fasteners are located adjacent to the major panel ribs and
need not be removed. When the Hugger
is installed atop these fasteners they may cause the base flange of the new
Hugger to bend, this is normal.
Fasteners located in the center of the existing roof pan can cause
sub-purlins to roll or “porpoise” these fasteners would need to be
removed. Special punching by Roof
Hugger may be possible to minimize the removal of existing roof fasteners
located in the center of the existing roof pan. Consult Roof Hugger to review options.
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J. Removal of Existing
Roof Fasteners:
1. Do not remove existing roof fasteners unless
installation of sub-purlins over fasteners causes sub-purlins to roll or
“porpoise”. Some distortion of base
flange of sub-purlins caused by existing roof fasteners is normal.
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Specifier Notes: In colder climates, special attention
should be given to flashing the opening created by removal of the existing
skylights to minimize migration of warm, moist air into this cavity.
Delete the following paragraph if there are no existing
skylights.
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K. Existing
Skylights:
1. Install sub-purlins over existing skylights.
2. Cut out existing skylights after sub-purlins
are installed if new skylights are to be installed over existing skylights.
3. Trim openings as required.
