Foam Closures · Metal building trim guide
Inside Foam Closure Strips for R-Panel and PBR Metal Roofs and Walls
Inside foam closures fill the gaps under panel ribs at the eave and base, blocking wind, rain, birds and bugs.
Also called: inside closure strip, foam closure, eave closure, rib closure, bottom closure
Inside foam closure strips are foam pieces cut in the shape of the panel's ribs. They go under the roof panel at the eave, and behind wall panels at the base, to fill the open gaps where the ribs end. Without them you can see daylight through every rib, and so can wind, rain, wasps and birds.
They are a small part with a big job. This guide covers what inside closures do, how they differ from outside closures, how many you need for a real building, and how to install them so the eave and base stay sealed.
What Is an Inside Foam Closure?
R-panel and PBR have tall ribs about every 12 inches. Where a panel ends on top of the framing, each rib leaves an open tunnel. An inside closure is a strip of closed-cell foam molded to fit up into those ribs from below, so the panel sits down tight on it.
It blocks wind-driven rain from blowing up the ribs, keeps out birds, wasps and rodents, cuts down on dust and drafts in an enclosed building, and helps insulated buildings hold air. It also gives the eave and base a neat, closed look.
Where Inside Closures Go on a Metal Building
Inside closures go under the panel. The main spots are the eave of the roof, where the panels sit on the eave strut or purlin, and the bottom of the wall panels, between the panel and the base trim or base angle. They are also used where wall panels stop above a door, window or wainscot line, and under cut panel ends along a valley.
An outside closure is the opposite. It sits on top of the panel, under the ridge cap, high-side trim or roof-to-wall flashing. Same idea, different shape. Most roofs need both kinds.
Inside Foam Closure Strips: Sizes, Profile and Material
Closures are commonly about 3 ft long, covering one panel width, and are made from closed-cell foam that does not soak up water. Some come with an adhesive back.
The one thing that matters most is profile match. The closure must fit your panel's exact rib shape and spacing. R-panel and PBR closures are often the same shape, but check with your panel supplier; corrugated and other ag panels take completely different closures. Closures are not colored like trim; they hide under the panel. Ask us how they are packed when you order.
How Many Inside Foam Closure Strips to Order
Formula: for each row, run length / 3 ft (the R-panel and PBR coverage) = closures, rounded UP. Add up every row: each eave, the base of each wall, and any openings or wainscot lines. Then add about 10% for cuts and ends.
Worked example: a 30 x 40 gable building with 12 ft walls and a 3:12 pitch. Roof only: each 40 ft eave needs 40 / 3 = 13.3, call it 14 closures. Two eaves = 28 inside closures. If the building is enclosed, add the wall base: the perimeter is 140 ft. Take out a 10 ft roll-up door and a 3 ft walk door, leaving 127 ft. 127 / 3 = 42.3, call it 43. Total 28 + 43 = 71, plus 10% = 79 inside closures.
The outside closures for the ridge are counted separately: 14 per side, 28 for this roof.
How to Install Inside Foam Closure Strips
The common method on a sealed building is a sandwich: tape, closure, tape, then the panel. Open carports are sometimes done without tape or without closures at all, but sealed is better.
- Set the eave trim or base trim first if your building uses it.
- Run a strip of butyl tape along the top of the eave strut, purlin or trim flange, right where the panel ends will sit.
- Press the closures onto the tape, starting at the end where your first panel will go, so the humps line up with where the panel ribs will land. Butt the ends together tightly; do not leave gaps.
- Run a second strip of butyl tape across the top of the closures.
- Set the panel on the closures and check that every rib sits down over its foam hump.
- Fasten through the panel, closure and tape into the framing with #12 or #14 roofing screws in the flats next to each rib. A slightly longer screw may be needed to reach through the foam.
- At the last panel, cut the closure to length so no open rib is left.
Common Closure Mistakes to Avoid
- Buying closures for the wrong panel profile; they will leave gaps or will not seat.
- Mixing up inside and outside closures. Inside goes under the panel; outside goes on top.
- Letting the closures drift out of line with the ribs as you work down the eave.
- Leaving gaps at the butt joints between closures.
- Using screws too short to reach through panel, foam and framing.
- Forgetting the base of the walls and the tops of openings on an enclosed building.
What to Order With Inside Closures
Closures work with the trim at the same edge. Order these together:
- Eave trim or gutter for the roof eave.
- Base trim for the bottom of the walls.
- Outside foam closures for the ridge, high side and wall flashing.
- Butyl tape, enough for two strips per row.
- Color-matched roofing screws long enough to reach through the foam.
Get Inside Foam Closure Strips in Houston From Ironrod Steel
Ironrod Steel Co. rolls its own R-panel and PBR panels and supplies the closures that fit them, inside and outside, along with trim, butyl tape and screws. Tell us your building size and whether it is open or enclosed, and we will count the closures with the rest of your trim list. Pick up at 8122 Hillsboro St in Houston or ask about delivery across Houston and Southeast Texas. Call or text (281) 902-7619.
Inside Foam Closure FAQ
What is the difference between inside and outside closures?
Inside closures go under the panel and fill the ribs from below, mainly at the eave and the base of the walls. Outside closures sit on top of the panel and fill the ribs from above, under the ridge cap, high-side trim or wall flashing.
Do I really need foam closures on a carport?
An open carport will stand without them, and some are built that way. Closures keep out wind-driven rain, birds and wasps, so most owners want them, and enclosed buildings should always have them.
Are R-panel and PBR closures the same?
They are often the same shape because the ribs are close to identical, but it depends on the panel maker. Check with your panel supplier. Corrugated and other ag panels need different closures.
How many inside closures do I need?
Divide each run by 3 ft, the coverage of one R-panel or PBR sheet, and round up. A 40 ft eave takes about 14. Add up every eave, wall base and opening, then add about 10% for cuts.
Should closures be set in butyl tape?
For a sealed building, yes. A strip of butyl tape under the closure and another on top makes a weathertight sandwich with the panel. Open carports are sometimes done without tape.