Question about rigid insulation in roof

[Living The Dream]

Hi all,

I am going to be insulating the roof of my old fleet with rigid insulation. I have a question for anyone that has done this before.

This picture shows the bare roof:

So in the roof the five aluminum bars in the middle are 1.5 inch deep, while the perimeter tubing is only 1 inch deep. My understanding is this is to give the roof a bow so water runs of the roof.

My question is, what have others done when insulating the roof with rigid foam insulation. If I I want to add as much insulation as possible did you run 1.5 inch board in the center areas, and 1 inch in the perimeter channels. How did that work out for you? I was also thinking I could just run 1 in deep all the way around, and then add reflectix in the spots that can accommodate.

Please share your success or failures if you have done this before. Or please share your ideas regardless if you have tackled this in the past.

Many thanks. Tim

 

[DonC]

check out the threads from people converting Sprinters and Ford Transits to campers - lots of sound and thermal insulation discussions and options. Rigid insulation does not seem to be commonly used. I find the rigid insulation in my 2012 Fleet to squeak in heavy winds and it offers almost no sound insulation from heavy rain.

http://sprinter-source.com/forum/forumdisplay.php?f=119
http://www.fordtransitusaforum.com/forumindex.php

 

[PokyBro]

Hey bud,

In addition to DonC's suggestion for some new, non-FWC ideas, I thought throughout the day, while driving up through Wyoming, about some possibilities.

1. You could use the 1.5" solid foam wherever it fits, and then go with 1" for the edges, filling in any gaps on the upper roof side, with fiberglass insulation, going from 1" back up to 1.5".

2. Same as above, but get 1/2" foam board for the edge sections, stacking it by 3 X, and doing a step down approach as you get to the 1" edges.

3. I think this last one might work best. Cut the 1.5" thick foam board to size, to fit in all the outside transition sections first. Then take those edge sections, and stand them up vertically, mark 1" on the edge needing to slope down, and approximately where the slope starts mid-board, so it would give you some guide marks to represent a wedge. Then use a good ole carpenters wood saw to take the slice out you need to remove. The foam board should cut easily, and you should be able to make more than one pass until you get the slope down to where you need it, probably roof side, while maintaining the flat, even side for the inside ceiling.
I would also try hard to make each section of foam board throughout, as snug as possible, so they stay in place, by tension.

This should also keep costs down, since you would only have to buy the one thickness, 1.5".

Hope that all makes sense, without a picture. Feel free to PM me if you want to discuss further.

Poky


Oh, and to answer your other question on attaching the wood slats on the ceiling, I just went with the 18 gauge staple gun. After being in cold weather for my first trip, I could imagine seeing screws in the slats potentially forming condensation, or perhaps ice during the night time, as there's much more surface exposed than staples. That aluminum tubing transfers cold temperature quite efficiently, so anything touching it will become close to the same temperature, and bringing that cold to the exposed surface of the screw head.



Sent from my iPad using Wander The West

 

[RC Pilot Jim]

Our experience with our 2012 Eagle same as Don C. Ours also "oil cans" - (pocka-pocka) in high cross-winds.

Since we added the rigid 150 watt panel (26 pounds) we have had no repeat of the "oil-canning" or the squeeking as the panel is right above our heads. f we know in advance the wind direction we try to nose into wind.

To aid sleeping we insert ear plugs

 

[smlobx]

As a builder I have another alternative.
The best insulation you can use is closed cell foam and the key is to completely fill all the voids with insulation. This is very hard to do with rigid boards.
If you can find a spray foam insulation company in your area they might be able to spray it for you.
The foam will expand then when cured you can "shave" it to the top of your channels.
Closed cell foam has an R value of 7 per inch. It will be very solid and actually adds some structural integrity to the substrate it is applied to. It will also be quieter.

 

[cdbrow1]

As a builder I have another alternative.
The best insulation you can use is closed cell foam and the key is to completely fill all the voids with insulation. This is very hard to do with rigid boards.
If you can find a spray foam insulation company in your area they might be able to spray it for you.
The foam will expand then when cured you can "shave" it to the top of your channels.
Closed cell foam has an R value of 7 per inch. It will be very solid and actually adds some structural integrity to the substrate it is applied to. It will also be quieter.

This is similar to what Vehicle OEMs are doing now. My Caddy is more glued together with foam than welded or bolted together. All to combat noise and squeeks.

 

[Living The Dream]

Thanks all for the feedback! I actaully called up ATC too to see what the could share about the modern camper insulation.

ATC says they use fiberglass mat duct insulation in their roofs Because it has a higher r value above rigid. I am guessing it is something like this:
https://www.zoro.com/johns-manville-duct-insulation-1-12-x-48-x-25ft-670378/i/G3618982/?gclid=Cj0KEQiA9ZXBBRC29cPdu7yuvrQBEiQAhyQZ9GzKv0jk0lzN83NgLHH74f8ay_yDGBO5y_biiRcN3XYaAjRN8P8HAQ&gclsrc=aw.ds


I like the spary foam idea, but that sounds kind of pricey. I think I will just head to the store tomorrow morning and figure out what options I have and go from there. Either rigid custom fitting the rigid or just going with some fiberglass batt insulation since it seems to work even in the modern campers. I might even mix it up and do one layer of refletix and fiberglass.

 

[kmcintyre]

BTW, I used screws for the wood slats. No issues.