Flatten arc or not?

[Chris C]

My design is a modified Cub/Modernaire/Modernistic. (or whatever one wants to call it.) I want to install a Fantastic Vent in the top. To those of you who've been in that same situation, I ask: Do you flatten the arc for 17" to provide a flat mounting surface for the fan, or do you just apply lots of sealer to fill the gap? Comments please.

[Kevin A]

My design is a modified Cub/Modernaire/Modernistic. (or whatever one wants to call it.) I want to install a Fantastic Vent in the top. To those of you who've been in that same situation, I ask: Do you flatten the arc for 17" to provide a flat mounting surface for the fan, or do you just apply lots of sealer to fill the gap? Comments please.

Chris,

Couldn't you build a shallow wooden frame work that fit in the roof that would provide a flat area for the vent to mount in, without flattening your roof line?

[Darren]

Chris, I'm attempting to do it like Kevin said. Keep the side profile curved and have a flattened area for the vent. You can slightly see the flat areas in the front and rear views.

I'll let you know if it works out alright.

[mikeschn]

The Lil Diner has a gentle arc where the roof vent mounts, and it seals up tight. So yea, you can leave your arc as planned.

Mike...

[Ken A Hood]

Just wondering if the trim piece from Scott (fantastic Vent) would work. The one for the airstream has a slight curve, going side to side. Could it be turned 90 degrees and used front to back?

[Chris C]

Mike,

If I screw the fan down in the center, (fore to aft) there will be a little over a quarter of an inch gap both fore and aft.

[Chris C]

Kevin and Victor,

Looks to me like another place for a leak................in a really bad spot! Just my opinion though. I'll be interested in seeing how well it turns out for you. Think I'll stay with just one hole in the roof.

[asianflava]

Chris, mine is exactly what you described. The flat spot on my roof is about 20in. Unless you knew to look for it, you'd never notice.

[Gage]

Yep that's what I was going to say. Just install it and don't worry about it. It will conform.

Have a good day

Now go buy some plywood.

[Kevin A]

Kevin and Victor,

Looks to me like another place for a leak................in a really bad spot! Just my opinion though. I'll be interested in seeing how well it turns out for you. Think I'll stay with just one hole in the roof.

Yup, and that's why you won't see a roof vent in my tear. However, you DID ask for advice on how to accomplish the installation and for ideas on keeping the original contour or building a flattened area. I offered a suggestion that apparently wasn't appreciated. Obviously, you're going to have to spend a little time eliminating leaks no matter how you go about installing any roof vent. With your woodworking back ground that task shouldn't be that difficult for you.

[Arne]

Roof vents don't leak. Or, I've never had one leak, nor heard of one leaking.... They have a gasket. Then you put silicone dabs on each screw....

People talk about these things like they are mounted in a submersible and have water under pressure just trying to push in. As far as this topic, I would not bother putting a flat spot in the roof. I would mount the vent at the top of the arc, with a screw on the middle of each side. Then I would cut strips to put under the front and back, of equal height and put in the gaps. On the side gaps, I might bother to put in tapered strips.

There are about 6 screws on each side, or about 20 total. To hold down a 14 x 14" vent. The strips mentioned above would be set in about 1/4 inch, and some type of caulk would be used to fill the gap..... done.

[Chris C]

Oh Kevin, I meant no offense! Honestly. I just don't want to have any more joints in the top than I have to. Sorry if my response came off wrong. Just not sure what to do here. Guess I'll go ahead and provide a flat spot in the curve.

[madjack]

Chris, I think if I were you I would just make it curved and then take one o' them scrapers you are so fond of and scrape a flat spot for the vent to sit/seal to.......
madjack

[An Ol Timer]

Today my grandson and I were putting the centercoard case into the sailboat that we are building for him and all I could think of was "Boy those guys and their paranoia about leaky roof vents sure wouldn't make boatbuilders."

[Chris C]

Chris, I think if I were you I would just make it curved and then take one o' them scrapers you are so fond of and scrape a flat spot for the vent to sit/seal to.......
madjack