kimberwarden
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17' 64 Oasis
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Post by kimberwarden on May 5, 2015 14:09:45 GMT -8
The underbelly of my Oasis is made from something that looks a lot like the stuff they make pegboard out of. Is it pressboard? It is in terrific shape, and I can't figure out why, since it must surely get sopping wet on a regular basis. I had to remove some of it in pieces to rebuild the framing under the door and I'm wondering what to replace it with and how to seal the seams. What does everyone else use?
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Post by vikx on May 5, 2015 21:59:29 GMT -8
Home Depot sells "soundboard" which is fibrous layered 4 x 8 sheet. Undercoated, it closely resembles Celotex. Celotex is the original belly in many older trailers. It added some insulation value. Usually resting on the metal frame, it could compromise the anchor bolts over time. (compression factor)
I've used Coroplast, like plastic cardboard but it is too waterproof. Metal bellies are waterproof and tend to cause severe floor and joist rot. Think warm soup cooking the wood... So, if Coroplast vents, it may be OK, but not totally sealed.
My latest full build has an 1/8" masonite belly, undercoated on the exposed side. It is easy to install, anchors securely to the floor joist and provides protection for the insulation. It "might" breathe a little, thereby reducing the sweat/condensation in the floor
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iamvoldemort
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196? Trailblazer 14'
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Post by iamvoldemort on Jul 2, 2017 8:53:07 GMT -8
Home Depot sells "soundboard" which is fibrous layered 4 x 8 sheet. Undercoated, it closely resembles Celotex. Celotex is the original belly in many older trailers. It added some insulation value. Usually resting on the metal frame, it could compromise the anchor bolts over time. (compression factor) I've used Coroplast, like plastic cardboard but it is too waterproof. Metal bellies are waterproof and tend to cause severe floor and joist rot. Think warm soup cooking the wood... So, if Coroplast vents, it may be OK, but not totally sealed. My latest full build has an 1/8" masonite belly, undercoated on the exposed side. It is easy to install, anchors securely to the floor joist and provides protection for the insulation. It "might" breathe a little, thereby reducing the sweat/condensation in the floor I was searching the forum for the same thing so I appreciate the help Vikx! I am re-building a '63 Trailblazer from the frame up currently and I originally got some 3/4 plywood sheets and was coating them. But than I realized I cant have 3/4 plywood, the frame and another layer of 3/4 plywood. I couldn't really see the original build and what they used because it was rotted and basically sitting on the ground when I picked up the trailer. Thanks for all the great info! |
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62ham
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62 Oasis
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Post by 62ham on Jan 26, 2018 11:18:19 GMT -8
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nate
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1963 Comet 17'
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Post by nate on Jan 26, 2018 12:23:47 GMT -8
My trailer had the foam board directly underneath the plywood floor, on top of the frame rails. The material mostly stayed intact over 50 years. It might get a little wet but it dries out. My understanding is that if it is sealed underneath, any moisture that enters above the floors (walls, windows, ceiling, etc.) will pool on top of the barrier and rot out the floor, rather than be allowed to run out of the camper or dry out.
I plan on NOT replacing the 'soundboard' material. Instead, I plan to lay the plywood floor directly on top of the frame rails and insulate between the frame rails and put 1/8" masonite board underneath to hold it in (like vikx explained above), painted on the bottom with fence paint.
Soundboard will compress over time which might loosen up the floor mounting bolts. It doesn't give much of an R value.
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62ham
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62 Oasis
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Post by 62ham on Jan 26, 2018 12:58:19 GMT -8
Nate, I put my floor directly on the rails. What will you use to insulate between the rails? Foam sheeting or?
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mobiltec
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1954 Jewel In Progress...
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Post by mobiltec on Jan 26, 2018 17:00:27 GMT -8
The underbelly of my Oasis is made from something that looks a lot like the stuff they make pegboard out of. Is it pressboard? It is in terrific shape, and I can't figure out why, since it must surely get sopping wet on a regular basis. I had to remove some of it in pieces to rebuild the framing under the door and I'm wondering what to replace it with and how to seal the seams. What does everyone else use? Under belly is made up of one of two materials. Either aluminum which is just a metal roof but flat. They use the same exact Acme seams as the roof. The aluminum makes the best under belly. The rest of the cheepos used masonite.... Same thing peg board is made from... The Celotex that Vikx was talking about is an under layment just under the plywood floor. An Under Belly goes on the bottom of the floor framing between the bottom of the floor framing and the metal chassis. |
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Post by Deleted on Jan 26, 2018 17:45:00 GMT -8
The Masonite as an alternative, and preferred by some, to metal or Celotex for the actual under belly that Nate is referring to. This would then be coated with some weather resistant material. I believe Vikx likes a fence paint product. We'll let her respond next. I have (3) trailers that have metal and (2) that have the Celotex as underbellies as original.
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Post by vikx on Jan 26, 2018 19:32:24 GMT -8
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CorvettCrzy
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'58 Corvette, '64 Franklin
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Post by CorvettCrzy on Jan 28, 2018 19:27:38 GMT -8
@vikx I'd really like to see your photo, i'm confused about the layers. Aren't the floor joists incorporated between the frame rails?
Plywood floor plywood floor I saw someone plywood floor
metal frame masonite floor joist with insulation between
masonite metal frame plywood
metal frame
how does one keep insulation in between the floor joist and metal frames from falling out?
Obviously, I need pictures.
Pretty sure ours is just coated plywood on metal frame, nuttin else.
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Post by vikx on Jan 28, 2018 20:21:07 GMT -8
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mobiltec
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Post by mobiltec on Jan 29, 2018 13:10:30 GMT -8
This has a metal under belly. The metal skin which is made just like a roof with acme seams goes on top of the metal chassis. Then the floor framing goes on top of that. Insulate between cells and then plywood flooring on top. Everything is carriage bolted through the chassis. Looking under the trailer.  Exposed framing and belly pan from the top...  Insulation and framing looking from the top...  Plywood floor installed over it all...  |
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Post by Deleted on Jan 29, 2018 14:56:42 GMT -8
Mobiltec's solution is great when you have the headspace inside the trailer to allow for everything to be above the steel trailer framing. Vikx is referring to a couple options when you don't have that luxury and need to build the floor within the steel framing of the trailer. I'll need to use the Vikx option for my Catalina shown to the left as it is relatively short.
Make sense??
Separate question for Mobiltec. Is there a reason you used batt insulation instead of rigid foam? |
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mobiltec
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Post by mobiltec on Jan 30, 2018 7:08:35 GMT -8
Mobiltec's solution is great when you have the headspace inside the trailer to allow for everything to be above the steel trailer framing. Vikx is referring to a couple options when you don't have that luxury and need to build the floor within the steel framing of the trailer. I'll need to use the Vikx option for my Catalina shown to the left as it is relatively short.
Make sense??
Separate question for Mobiltec. Is there a reason you used batt insulation instead of rigid foam? On the first part of your comment, I didn't design this trailer. Shasta did. I just replaced all the rotten part. On the rigid foam, I just have never used rigid foam for insulation. Shasta used fiberglass in the floor and I see no reason to change. I've never really liked the idea of using rigid foam. About the only place I do use it is around the refrigerator or ice box. Everywhere else I use fiberglass. When insulating the walls I have found that fiberglass also pushes out on the metal some giving me what I call the "Puff Factor"... You'll have to see my Colorado build of the 59 Forester to see what the "Puff Factor" is. That video series is listed on my website. |
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