Roof Vent Cap Duct Collar

We had our bathroom remodeled and the contractor installed a Panasonic ceiling fan with the exhaust going through the roof and into a Broan hood. It would have been a whole lot easier if he bought this collar and installed it on the Broan hood right from the start. Instead, he just cut a 4.5" hole through the roof and loosely tack-nailed a 4" elbow into the side of the hole. I figured it wouldn't be to hard to install this after the fact from inside the attic. I'd seen other reviews where homowners tried to retrofit a DC-4 collar into an existing roof-mounted hood, and some reviewers expressed difficulties. It was impossible for me too, but I found a work-around. I couldn't align the tab on the DC-4 collar with the slot in the Broan housing that had already been installed on the roof. I had two problems. First, I couldn't see up into the housing to align the tab on the DC-4 with the slot in the Broan housing. Second, the contractor mounted the exterior Broan hood way off-center to the hole through the roof, meaning that I would have to cut a really huge hole in the sheathing to align the two. My work-around was to install the DC-4 backward, with the smaller crimped end through the hole in the sheathing. The crimped end extended well into the hood but did not interfere with the damper. The shoulder of the larger end of the DC-4 collar actually fit snugly against the 4.5" hole he had cut in the sheathing. I secured the DC-4 to the sheathing with (4) stainless steel 1" brackets, stainless bolts, washers, and nuts. I screwed the other ends of the brackets directly to the sheathing with 3/8" stainless screws that were short enough for a secure connection, but not long enough to penetrate the sheathing or rain/ice barrier. Then I installed a standard 4" duct elbow to the DC-4 collar with the male end inserted into wide end of the DC-4, securing it with foil tape. I ran a length of insulated flex duct to connect the fan to the elbow that was attached to the DC-4. This retrofit solution worked out well for my situation. The connection through the roof is very secure, even without a direct metal-to-metal connection between the DC-4 collar and the slots in the Broan hood. Another option would be to go up on the roof, remove the Broan hood, connect the collar directly to the slot as designed, and re-install the hood. I chose not to do that because I didn't want to risk creating a leak by disturbing the shingles and exterior caulk, which I knew were weathertight. As for the DC-4 collar, it is very sturdy and high quality. I highly recommend it, even if you do have to install it backwards!

This is pricey for what it is, but as long as there is enough access through the hole in your roof to line up the collar, it was effortless. If the hole cut in the roof is not squared up or big enough to access the bottom of the vent then I foresee it being a headache. If you’re working in a tight space, I also advise clamping your vent hose on to the collar first and adjusting it after getting the collar placed into the roof vent.

Ordered this replacement for my kitchen and bathroom fans to vent out the roof collars. The roofers disconnected the vents and threw away the old connectors and just left the duct work laying in the attic. It was easy to attach these replacements

Fits right, durable , easy installation

this is basically a proprietary 4" collar. It's nothing special except that it twists into certain Broan 4" caps, and it doesn't even do that all that easily. It works and it's mildly convenient but it's ridiculously expensive for what it is, and even it were half the price I'm not sure that would be a great value either

This was essentially impossible to install from inside the attic, after the roof had been installed. It would catch but couldn't be threaded around the hole in the vent. Since I blame the roofer, I only took off one star.

Excellent quality, THICK duct collar. Used this collar to install two Panasonic ventilation fans in my two home bathrooms. Perfect fit between this collar and the (Broan-Nutone 636) roof vent cap (also reviewed). The non-serrated end of this collar screws securely into the bottom of the roof cap with just a gentle twist. No rivets or screws needed. Other collars of similar type stocked at the two local BORGs were flimsy a-few-gauges thinner sheet metal. Go Broan-Nutone products, you won't regret it.

This is a hard to find item. The roofer only installed the vent and I guess they took this critical part. Just glad I finally found it without having to buy the entire kit! Works as advertised and very easy to install