A metal roof with open ribs at the eave and the ridge leaves a gap between the panel and whatever sits beside it. Closure strips fill that gap. They are cut to the rib profile of the panel, so the panel sits on them flat, and they keep wind-driven rain, snow, insects and birds from getting into the ribs. The roof spec should say which closure goes where, what it is made of, and when it goes in. Most homeowners never see the strip once the job is finished, which is why it tends to disappear from a bid.
Material and spec
Closures come in a few forms. On corrugated and ribbed metal panels, the common product is a closed-cell foam strip pre-cut to the rib shape, often with an adhesive face. Some installers use a rubber or EPDM profile, and some use sheet metal closure pieces formed on a brake, usually at the ridge where the panels meet the ridge cap. A standing seam panel works differently. Its seams are raised, so the closure work happens at the panel ends, at the eave and at the ridge, using formed metal pieces that match the seam height. An eave closure on a standing seam roof is a formed piece, not a foam strip, and the spec should say so in those words.
The profile has to match the panel. A closure cut for one rib shape will not seat under a different one, and a strip that is slightly too narrow leaves a channel where birds nest and where water sits against the panel. Write the panel profile name into the roof spec, not just the word closure. The same goes for the material. Foam ages under ultraviolet light, so the spec should name the closure product and its UV rating if the manufacturer publishes one. Ask whether the foam is closed-cell. Open-cell foam takes on water and holds it against the metal, which is the opposite of what the strip is there to do.
The order of installation matters as much as the product. Eave closures usually go down before the first panel, set against the trim or the drip edge, so the bottom of the panel rests on them. Ridge closures go in at the top before the ridge cap is fastened, tucked into the open rib. If the spec does not state the order, ask the installer to walk you through it before the crew starts. A closure set after the panel is already fastened often has to be lifted to seat correctly, and a lifted closure is where the gap begins.
St. Louis weather tests this detail in specific ways. Spring and summer storms push rain sideways, so an open rib at the eave can take water in even when the panel itself is tight. Freeze-thaw cycles in winter work on anything that was set loosely. A foam closure that was never pressed firmly against the panel can shift as the metal expands and contracts, and the gap it leaves will show up in the first hard winter rather than on the day of the final walkthrough. Firm seating is worth asking about by name.
What it costs
Closures are a small line in the price of a metal roof, usually priced per linear foot of eave and ridge or per piece. The material is inexpensive. The labor is in the cutting, the fitting and the set, and in any second trip needed to replace a closure that was put in wrong. What drives the number is the length of open eave and ridge on your house, not the square footage of the roof. A simple gable roof with a long eave may carry less closure footage than a hip roof with several ridges and short runs.
Ask for closure lines to be listed separately. A bid that folds closures into a general metal trim figure hides both the quantity and the product. When you compare two metal bids, the closure lines should show the same linear footage and the same product name. A bid that lists closures at the eave but not at the ridge, or that lists none at all for a roof with ribbed panels, has left out work that will still happen once the panels are on the deck.
On a roof with many hips, valleys or dormers, the closure footage can be larger than most people expect. Count the ridge, the hip lines, and any eave that runs past a dormer or a change in pitch. The count should come from the roof measurement you were given, not from a number that was estimated from the street. If two bids use different footage for the same house, the difference is worth a written question before you choose.
Closures also carry a cost that does not show up in the price. A strip that fails early can let birds into the ribs, and a bird nest in an open rib is a repair call that a closure would have prevented. The cheapest closure in the bid is not always the one that holds up. Compare the products as named, not the line totals alone.
What to ask
- Which panel profile will the closures match, and is that profile name written into the spec?
- Is the closure foam closed-cell, rubber, or formed metal, and what is the product name?
- Where are the closures placed: at the eave only, at the ridge only, or at both, and what happens at the gable ends?
- What is the installation order relative to the panels and the ridge cap?
- How many linear feet of eave and ridge does the closure line assume?
- Who checks that each closure is seated before the trim goes on, and will you see the strip in place before the crew leaves?
Missouri roof work runs through permit desks in many St. Louis County communities, and the closure detail usually does not appear on the permit application. That is why it belongs in the spec you sign, not in a conversation at the door. A closure line you can read is one you can check on the day the crew is working.
If you have a metal roof on the calendar and want to see the closure specification written for your house before you commit, Keys Roofing can be reached at (314) 220-2333. Ask for the eave and ridge closure lines by profile name, and ask for the footage each one assumes.