Standing seam metal costs more up front and less over the life of the building, and the bid turns on one item most people forget to price: what happens when the snow lets go. A smooth metal roof sheds snow in a sheet. In Coeur d'Alene, ID, with a long winter and a design snow load of 60 psf, a slide off a metal roof can take out a gutter, bury a door or hit a person. Snow guards are not an accessory here. They are a line in the base bid.
We price the panels, the clips, the underlayment and the snow retention separately, so the owner sees what the system costs and where the money goes.
The Call: When Metal Beats a Membrane
Metal wins on slope. A roof with real pitch sheds water and snow, and standing seam panels with concealed fasteners keep screw heads out of the weather. It wins where the owner wants a long service life and a clean look, where the structure is a pitched steel frame, and where the building will be held long enough to spread the first cost. It also wins at the end of a membrane roof's life on a building that has enough slope.
It loses on low-slope roofs where a membrane drains better, and on roofs with so many penetrations that panel details become a cost. We show a membrane alternate on any roof where either could work. For existing metal roofs that are tired but sound, a metal roof retrofit may be the cheaper path.
What It Costs: Panels, Clips and Underlayment
Five lines carry the bid. Panel gauge and finish, which set the material price. Clip type and spacing, which set wind and thermal performance. Underlayment, which in this climate includes an ice barrier at eaves and low-slope areas. Trim and flashing, which is hand-formed and labor-heavy. And snow retention, priced by the foot of guard line. Tear-off is its own line, and a metal retrofit over an existing roof can avoid it.
Panels are often roll-formed on site or to order, so lead time is a schedule item. We order after the field measurements, not from drawings alone, and we confirm the panel profile with the GC before we release the order. A wrong length is a week lost.
Trim is where labor hides. Eave, rake, ridge, valley and wall flashings are bent and fitted by hand, and a roof with many transitions costs more than the square footage suggests. We count linear feet of trim before we price, and we show it as a line. Penetrations through metal use prefabricated curbs or pipe flashings that match the panel profile, and each one is priced by count, with skylight and penetration flashing detailed to suit the seam spacing.
What the City Sheet Says: Snow, Wind and Ice Barrier
Three numbers on the city sheet reach a metal roof directly. The snow load sets the clip spacing and the panel gauge. The wind speed sets the clip pattern at corners and perimeters. The ice barrier requirement sets the eave and valley details, where meltwater refreezes and backs up under panels.
We lay self-adhered ice barrier at the eaves and any low-slope run, lap it correctly and keep it under the panels and metal drip edge. A windstorm like the one in November 2015 is the reason we do not skimp on perimeter clips or edge trim.
Thermal movement belongs here too. Steel and aluminum panels grow and shrink with the temperature, and a place that swings from a record low of minus 30 F to more than 90 F on some summer days asks the clips to slide freely. We specify clip travel for the actual panel length, and we avoid fixing a long panel at both ends.
Snow Behavior: Slide, Guards and Where It Lands
A snow guard system is a set of rails or clips fastened to the seams that hold snow on the roof until it melts gradually. The layout depends on the slope, the length of the run, the panel type and what sits below. Over a walkway, an entrance or a lower roof, we run guards in staggered rows. Over open ground, a lighter pattern may do. We mark the layout on the roof plan and price it by the foot.
Snow does not need to be as deep as it is east in the Silver Valley, where Mullan averages over 100 inches a year, to cause a slide. Post Falls at about 59 inches is enough. A roof that sheds onto a parking lot full of cars is a claim waiting to happen. We ask the owner what is below every eave before we recommend a layout.
Gutters and downspouts need the same planning. Snow and ice sliding off a metal eave overloads a standard gutter, so we use heavier hangers or leave the gutter off and let a drip edge carry the water to a drain below. Where edge metal and gutters are part of the scope, we price them with the guard line so the two are designed together.
Where It Fits: Hangars, Offices and Pitched Commercial Buildings
Coeur d'Alene Airport sits inside Hayden, with a 7,400 foot runway and 294 based aircraft in 2018. Aviation buildings such as hangars often use metal roofs because of their spans and slopes, and Empire Airlines and Rocky Mountain Construction are headquartered in Hayden. Metal also suits pitched office buildings, churches and some warehouses and shops across the Rathdrum Prairie.
Retail and light industrial at Post Falls can also take metal if the structure is pitched. For low-slope roofs on the same sites, TPO and the other membranes are the practical choice. We confirm slope on a measured plan before we recommend either.
Church and civic buildings with pitched roofs and long sightlines also use standing seam, because the lines run clean from ridge to eave and the concealed fasteners keep the surface uncluttered. On those, we spend extra time on trim, since every visible joint is a joint the owner will look at for years.
Schedule: Metal Goes On Fast Once It Arrives
Panel install is quick compared with a membrane. The schedule risk sits in the lead time for panels and trim, and in cold, icy mornings when the roof is slick and unsafe. We schedule the install for late spring through early fall, build in weather days and keep fall protection in place on every shift. When the dry-in matters, we install underlayment the same day the tear-off opens.
Closeout covers clip spacing checks, seam closure, fastener counts on trim and a final walk with the GC and photographs of the guard layout. The panel maker's warranty paperwork and the finish warranty go to the owner with the as-built notes.
Commercial Roofing Questions
Do we need snow guards?
Almost always, on roofs with slope and anything below the eave. We lay out the guard line on the plan and price it by the foot.
Will a metal roof be noisy in rain?
Over insulation and a solid deck, rain noise is modest. Open framing without insulation is louder.
Does metal expand and contract?
Yes, and the clips are designed to let the panels move. A fixed panel buckles or opens a seam. We use clips rated for the run length.
Can metal go over the old roof?
Sometimes, with a retrofit framing system. The structure has to take the added weight, and the old roof must be dry.
What about lightning and ice?
Metal does not attract lightning more than other roofs. Ice at the eave is handled with barrier underlayment and a heated edge where needed.