Raising a 14"x14" roof vent?

[dylanear]

Seems I'm going to need a spacer or riser of some sort to mount my new roof vent/fan without any part of it sticking below the ceiling. My 14x14 vent is between the door and stove and is a highly trafficked spot, I'm used to avoiding it after many months full timing, but it's still really annoying ducking even more than I have to for the low ceiling.

Anyway, my question is, how would you raise a vent 1/2 or a full inch?

I've found this video:

Fantastic Fan Spacer on top of 1976 Boler trailer - YouTube

That's the concept, but I'm hoping for a much simpler, cleaner and easier way. I'd really rather not use wood or fiberglass. I'm thinking some simple aluminum rectangular extrusion? Or maybe durable plastic sheet, 1/4" ish thick? I can cut a several layers to make a 14x14 "trim" and silicon them together to get the required thickness?

[dylanear]

This might work well, it's thick so hard to cut, but I bet I could use the router attachment on my Dremel and cut 1/2" plastic. Might be slow going.

Sheet, HDPE, White, 1/2 In Th, 24 x 24 In - Plastic Sheets, Film, and Flat Stock - Plastics - 3HMN4 : Grainger Industrial Supply

[Eddie Longest]

You can make a spacer out of PVC house trim boards from Lowes or Home Depot. It is white, comes in different sizes and is easy to work with. You can screw it and glue it together. If you want your spacer about 1" thick you can trim down the profile off of a piece of PVC brick mold.
Eddie

[Glen G]

Post a picture of the inside and how the fan sticks down.

If its just the trim ring, it can be cut down so it fits flush with the ceiling.

[dylanear]

Originally Posted by Glen G

Post a picture of the inside and how the fan sticks down.

If its just the trim ring, it can be cut down so it fits flush with the ceiling.

Of my current fan? Or the new one once it's complete?

I'd done a lot of research, it's not just a trim thing. My current fan does have trim I could remove, but there'd still be a metal box for the controls that would stick down and the switches further below that.

The Fantastic Fan, at least the high profile model will only stick down about 1/2 inch, but the opening/closing motor sticks down from there and then there's the manual knob on that. So it's looking like if I want nothing at all protruding than I'll need at least a 2 1/2" lift. But 2" will probably do, with just the knob sticking down some. Perhaps a lower profile replacement knob can be found.

Here's some great install info on the Fantastic Fans.
Fantastic fans pictures Fantastic vents

And an illustration of just how much lift I'll need to clear that knob entirely.
http://www.rvvent.com/images/highprofileautoknob.jpg

[Kenny Strong]

look at Lexal in a caulking tube rather than silly cone! Fortunately the opening in my Bigfoot is over the table top. I added 1-1/2" redwood spacer to the interior. All is good.

[pindraak]

If you haven't altered the fan, consider buying one that doesn't require a spacer. The Maxxfan goes down to roof thickness of 1 and 1/8th inches:

MaxxFan General Overview | Latest

[pindraak]

Here are pics of the Maxxfan on my Bigfoot. Roof thickness with shower enclosure was about 1.25 inches.

[floyd]

The "plastic wood" spindles used for decks are really good for fabricating the frame for the fantastic fan. It wears like plastic and works like wood.
You can screw into it (best to predrill) to attach the fan. it takes well to sealers etc. You could then cover it with an aluminum extrusion if you like.

[PhillyPhixy]

I used Sintra PVC for my spacer in the vent when I put the skylite and reinforced roof in my Trillium. Many suppliers and trade names (troxell, etc..)

Sintra® Board - Rigid PVC Plastic Sheets

[dylanear]

I didn't realize I was getting replies to this thread! Not sure how the email notifications are working.

Anyway, good materials info! But I've already started down a course of action. I have a plastics shop in town CNC machining a part out of thick polyurethane sheet, to hopefully precisely match the edge of the fan. Probably going to be about $150, not a cheap part, but I never want to mess with that again once it's installed.

[David Tilston]

I have a 9" vent on my latest Trillium. I will be putting in a 14" Fantastic fan. There is an approximately 1/4" high protrusion around the 9" vent hole that I was considering duplicating on a 14" hole. Maybe, I will go to a 1" protrusion instead. I think doing it in fiberglass makes more sense.

[Spanke]

Originally Posted by David Tilston

I have a 9" vent on my latest Trillium. I will be putting in a 14" Fantastic fan. There is an approximately 1/4" high protrusion around the 9" vent hole that I was considering duplicating on a 14" hole. Maybe, I will go to a 1" protrusion instead. I think doing it in fiberglass makes more sense.

I'm going to do the same for my "Trillium". I agree with you on the 1" protrusion and fiberglass especially after reading this thread: http://www.fiberglassrv.com/forums/f...ass-52498.html.

Spanke

[dylanear]

I got my parts, they look really good and solid, but it cost a small fortune. Ah, I wanted experience having precise parts made and I got that. $250 added to an already very expensive fan. Ouch, but I think I'll be very happy with the results.

[dylanear]

I'm just not entirely sure how to seal the parts I had fabricated. There's three layers to seal. Fan to first spacer, first to second spacer, spacer to roof. I have the butyl putty tape and was thinking perhaps of using that between the roof and spacer, then silicon between spacers and then not sure if butyl or silicon under the vent.

I'll get some pics posted of my spacers.

[dylanear]

I'm going to posts any updates to this in my new vent install thread.

Here: http://www.fiberglassrv.com/forums/f...-in-52923.html
But I'll put some pics of my spacers here for completeness.

Not in focus, sorry.



Both spacers and the FF in place for the first fitting.