Metal Roofing Accessories That Hold a DFW Roof Together

What Accessories Does a Metal Roof Need?

Every standing seam roof depends on five accessory families: clips, fasteners, underlayment, sealants and pipe boots. Each one does a job the panels cannot do alone.

• Clips hold panels to the deck and manage thermal movement.
• Pancake-head fasteners attach clips and cleats without telegraphing through the metal.
• Underlayment is the second waterproof layer, and it has to survive Texas roof temperatures.
• Sealants and butyl tape back up the laps at closures, trim and penetrations.
• Pipe boots seal plumbing vents and other round penetrations.

Homeowners get all of these as part of a PMRS roof, so there is nothing to buy separately. Contractors, builders and architects can request materials pricing, spec sheets and submittals for their own projects.

Standing Seam Clips: Fixed or Floating?

Clips are the concealed brackets that hold standing seam panels to the deck. A fixed clip pins the panel in place. A floating clip holds it down while letting it slide as it heats and cools.

Every metal panel moves. Steel changes length by about 0.0000065 inch per inch for each degree Fahrenheit, and aluminum by roughly twice that. On a 40-foot steel panel, a 150-degree swing from a winter night to a summer afternoon adds up to nearly half an inch. Pin that panel tight along its length and the movement has to go somewhere. It shows up as oil canning, elongated fastener holes or clips that tear loose.

Floating clips solve this with two parts. The base is fastened to the deck, and a sliding tab hooks the panel seam. The panel is locked in one fixed zone, usually near the eave or the ridge, and floats everywhere else. Our 2-inch mechanical lock spec sheet, for example, calls for a heavy-duty interlock clip that secures the panel while allowing expansion and contraction.

When Are Fixed Clips Enough?

Fixed clips work on short panels, where total movement is small, and in the fixed zone of a longer panel. Past a length the panel maker sets, floating clips become the rule. Long runs are where they earn their keep, and PMRS has installed roof panels as long as 100 feet on a past mechanical lock project.

Galvanized or Stainless Steel Clips?

Galvanized clips are the standard partner for Galvalume steel panels. Stainless steel clips go under copper and zinc, and they are often used under aluminum, because they avoid galvanic corrosion between unlike metals.

Clip spacing is engineered, not guessed. Tighter spacing raises wind-uplift resistance at edges and corners, and site-specific engineering is available on request. Profile details are on our standing seam, snap lock and mechanical lock pages.

Which Underlayment Goes Under a Metal Roof in Texas?

Under a metal roof in DFW, underlayment has to survive heat as well as water. We specify a high-temperature self-adhered membrane where water concentrates or slopes are low, and a synthetic or heavy-duty sheet across the open field where the system allows it.

Metal panels get much hotter than the air on a sunny day, and the underlayment sits right under them. Industry guidance notes that standard synthetics and SBS peel-and-stick membranes often top out around 180 to 240 degrees. High-temperature products are commonly rated from about 240 to 265 degrees.

A membrane that is not rated for the heat can soften, ooze and stick to the underside of the panels. Once it bonds to the metal, it fights the panel’s thermal movement. That is why our mechanical lock spec sheets call for Pro HT high-temperature underlayment at 3/12 slope and below.

Documents on file: the LASTOBOND PRO HT-N high-temperature underlayment product sheet (PDF), the LASTOBOND PRO HT-N instruction manual (PDF) and the Resisto waterproofing safety data sheet (PDF). More documents are on our downloads page.

Pipe Boots for Metal Roofs: Colors, Sizes and Retrofit

A pipe boot is a flexible flashing that seals a round pipe where it passes through the roof. Its soft base bends to the panel shape, and color options let it blend with the roof.

Each boot has diameter rings marked on its cone. The installer trims at the ring that gives a snug fit, so the boot stretches tight around the pipe. The square base has aluminum in it, so it conforms to the panel ribs and pitch before it is sealed and fastened.

Size up, not down. The smallest boot that fits leaves no flex to follow the roof’s movement. For the common 2- to 4-inch pipes, a No. 4 boot is the usual pick for a 4-inch pipe.

Which Boot Material for Which Pipe?

EPDM rubber boots suit ordinary plumbing vents. Hot pipes, such as furnace flues and wood-stove pipes, need silicone, because EPDM can break down early at high temperatures. Both resist cracking, UV and weathering. PMRS has listed a 20-year warranty on the boots it supplies; confirm the current terms with your quote.

Retrofit Boots and Colors

Retrofit boots split open and close around a pipe with a zipper-style seam, so an existing vent does not have to be cut or disconnected. Colored boots let a vent blend into the roof instead of standing out as a black ring.

Where Do Pipe Boots Belong?

• Plumbing vents, bath and kitchen exhausts, and conduit through the roof.
• Set the boot in the flat of a panel, never across a standing seam.
• If a pipe lands on a seam, we move the pipe or build a custom flashing.
• Chimneys, curbs and skylights need custom flashing and a cricket instead.

On a PMRS roof, pipe boots are priced at $200 per penetration. See custom metal flashing for larger penetrations and custom chimney caps for chimneys.

Can Contractors Buy PMRS Accessories?

Yes. Contractors, builders and architects can buy PMRS accessories with or without panels, plus flashing bent to their drawings. Request materials pricing, spec sheets, color charts and submittals through our contact page. Panel and coating documents are on our downloads page, and our services page covers take-offs and shop drawings.

Homeowners never need to shop for any of this, because every accessory comes specified and installed with a PMRS roof. Our team brings 20+ years of combined experience to those choices. Start with a free estimate.