Mueller U-Panel - Manual (Page 3)

This detail & installation manual has been provided to serve as a basic guideline for installing the Mueller R & U-Panel
roof system. This manual should be used in conjunction with the erection drawings to help ensure proper installation
of this roof system. In case of discrepancies, the erection drawings will govern over this installation guide.
It is the customer’s responsibility to ensure that a competent and experienced erection crew is chosen for the installation of
this roof system. It is also the customer’s responsibility to ensure the erection crew understands and follows this installa-
tion manual and the erection drawings.
Mueller, Inc. is not responsible for any problems or defects caused by improper erection techniques. Any questions in
regards to clarifying the intent of this manual or the erection drawings should be directed to Mueller’s sales department at
the address and phone number shown on the back cover.
Warning! When these panels are installed on roofs with less than recommended pitches (R-Panel recommended
minimum pitch is 1/2:12, U-Panel recommended minimum pitch is 1:12), heavy rainfall may lead to water accumu-
lation and possible leaks.
It is important that the roof be properly prepared before installation begins.
Decking
Mueller, Inc. recommends our metal roofing systems be installed over CDX plywood wooden roof decking with a min-
imum thickness of 15/32” or equal. Note: If using treated lumber, special corrosive resistant screws are required. Ask
your sales representative for more information.
Stripping
The removal of existing roofing and the associated fasteners is optional with R & U-Panels. This does not damage, and typ-
ically improves, the structural capacity of wood decks. During removal, many shingle fasteners may remain embedded in the
deck. These fasteners can be pulled out or hammered flush with the deck.
Repairs
Deteriorated areas should be removed and replaced with material to closely match the existing thickness. The deck
should be sound and smooth, with fasteners flush with the surface, prior to the installation of the metal roof. New wood
decking, whether boards, planks, CDX plywood, or equal should be the same thickness and have similar strength char-
acteristics and span ratings to that of the area being replaced. Deck fasteners that have backed out should have a new
fastener installed adjacent to it and the existing fastener should be removed. Loose or lifted boards, planks, plywood,
and corners should have additional fasteners installed to secure the existing deck in place.
Holes in wood decks that are 10" wide or less can be covered with 20-gauge steel. This steel plate should be galvanized
and must overlap the wood roof deck 4 inches minimum and be secured with fasteners 4 inches on center.
Fascia boards should be straight, level and in good condition. Any rotted or deteriorated boards should be replaced. All
roof framing and decking abnormalities will be transferred to the new metal roof if not corrected before sheeting begins.
Underlayment
New underlayment must be immediately installed over prepared roof decking. Mueller recommends Titanium or a
minimum 30# felt. This underlayment should be installed with a minimum of a 2" side lap and a 6" end lap.
Underlayment temporarily protects the roof decking against water penetration. It should be installed using galvanized tin
caps (not plastic caps). The underlayment should be fastened to the deck with galvanized roofing nails with tin caps 12"
on center in the field and 6" on center at the sidelap.
Flashing
Re-roofing projects incorporate metal flashing and metal counter-flashing. Some counter-flashing are embedded, such as a
masonry wall, or are installed behind existing siding. This metal, if not deteriorated, may be reused. The existing metal can
be cut, leaving approximately a minimum of 2" of flashing exposed, and new counter-flashing can be fastened to the back-
side of the existing metal. Counter-flashing must be slightly higher than the top of the rib on the sheets to be installed.
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PREPARATION REQUIREMENTS & RECOMMENDATIONS