DuraFlex Chimney Cap Installation Nationwide

DuraFlex Chimney Cap Installation: The Shelton Owner’s Guide

A properly fitted DuraFlex chimney cap installation in Shelton typically runs between $340 and $620 installed, depending on flue size and whether your chase needs flashing work. We stock DuraFlex-compatible caps for 6-inch through 12-inch round flues on our Shelton trucks, and most swaps are completed in under two hours. Homeowners usually discover the problem during the first hard rain of fall, when water starts hitting the firebox floor, or when they spot rust streaks running down the chimney chase after a wet winter like the ones we get off the Housatonic.

Call (475) 265-6822

Which DuraFlex Models This Applies To

DuraFlex produces three liner series that matter for cap fitment in Shelton homes: the standard 316Ti stainless flexible liner, the 304 alloy economy line, and the heavy-wall AL29-4C used with high-efficiency gas appliances. The cap you need depends on which liner is running through your flue, not just the chimney’s outside dimensions. We see a lot of the 316Ti in the 1980s raised ranches out by Bridgeport Avenue, where the original clay flue was relined during the conversion to gas inserts.

Check the top of your existing cap for a stamped size marking, usually on the collar or the underside of the lid. If the cap is too corroded to read, measure the liner’s outer diameter with a tape measure, not the flue tile. A 6-inch liner needs a 6-inch cap collar, but the chase cover flashing might be sized for an 8-inch or 10-inch tile opening. That gap is where water gets in, and it is why we carry both standard and oversized chase top flashings on every truck.

We are not affiliated with DuraFlex. We source OEM caps direct and also stock quality aftermarket equivalents from Olympia Chimney and Famco when the lead time on a factory part does not match the weather forecast. For most Shelton installations, the aftermarket collars seal just as well and carry the same stainless warranty.

Signs Your DuraFlex Chimney Cap Installation Is Failing

• Rust-colored staining on the chimney chase or siding. DuraFlex caps are 316Ti stainless, but the chase cover flashing that supports them is often galvanized steel that rusts through in 7 to 12 years in Connecticut’s freeze-thaw cycle. The cap itself may be fine while the flashing underneath rots out, letting water run behind the brick.
• Water in the firebox after rain, even with the damper closed. The cap’s mesh screen has pulled away from the collar, or the lid has shifted in wind. We see this on homes near the Shelton Lakes where the tree canopy blocks wind until a nor’easter hits straight on.
• Birds or squirrels nesting in the flue. The mesh sides of a DuraFlex cap are 5/8-inch weave, which stops animals unless a corner gets bent or a weld cracks. Once they are in, the nest blocks draft and creates a fire hazard.
• Draft problems or smoke backup on startup. The cap lid is too low, or the mesh is clogged with creosote flakes. DuraFlex caps need 5 inches of clearance between lid and collar for proper draw, and Shelton’s oak-heavy cordwood produces more creosote than the softwood blends burned farther north.
• The cap is missing entirely after a storm. This happens when the original installer used generic screws instead of the DuraFlex-specified stainless wedge anchors, or when a cap was forced onto a liner size it was not built for. The collar loosens, wind does the rest.

Replacement Cost & What’s Included

What moves the price: whether we are capping a straight liner top or replacing rotted chase flashing, whether the flue needs a camera inspection first to confirm liner condition, and whether your roof pitch requires a second technician for ladder safety. We give you the full number before we start. The number on the estimate is the number on the invoice.

Every DuraFlex cap installation carries our 90-Day Done Right Promise in writing. If water gets in, if the fit loosens, if anything is not right, we come back. No paperwork to dig up, no arguing.

DIY or Call Us?

There is no high-tension spring or electrical hazard on a chimney cap, but there is a real fall risk. Most Shelton chimneys are 25 to 35 feet to the roofline, and the older colonials up near Huntington Center have steep pitches with brittle composite shingles that do not forgive a misplaced foot. If you are comfortable on a roof with proper harnessing, you can check whether the cap is loose by hand, whether the mesh is intact, and whether the chase cover shows rust holes.

Where DIY goes wrong: forcing a cap onto a liner size it does not fit, using non-stainless fasteners that rust out in two seasons, and missing the cracked crown or deteriorated flashing that caused the original cap to fail. We document every installation with photos you can see and a plain-English verdict on the rest of the system. Russell Haines put it this way once, and it still governs how we work: “Tell me what it is, fix what needs fixing, leave the rest alone.”

If you are not set up for roof work, or if you want the condition of the liner verified while we are up there, call (475) 265-6822. A live person answers, 24 hours a day.

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