Thread Tools Search this Thread Display Modes
Old 04-29-2008, 09:36 AM   #1
3 Rivet Member
Ambie '64's Avatar
1964 28' Ambassador
Oklahoma City , Oklahoma
Join Date: Jan 2006
Posts: 143
Subfloor material dimension

I'm not sure if anyone has encountered this (or if I'm doing something different), but I removed all the sub floor in my trailer and saved the pieces to make templates from 4x8 sheets of MDF board. I figured this was more preferable than chopping up some expensive permanent material as I negotiated the curves and notches. The sub floor Is 88" wide and (!) 48 7/8" long when you include the dadoed 1" that the two overlapping pieces occupy atop the frame. Aside from wondering why they did this, my question is, do I need to buy 5' x 8' x 5/8" material? I can still use my templates, but will need to add that pesky 1" when cutting the real deal. Any help or suggestions would be greatly appreciated.
Ambie '64 is offline   Reply With Quote
Old 04-30-2008, 10:11 AM   #2
Rivet Master
Wabbiteer's Avatar
1973 27' Overlander
1972 29' Ambassador
St. Paul , Minnesota
Join Date: Apr 2006
Posts: 2,043
Images: 2
Blog Entries: 2
I used old floor sheet as template and wish I hadn't - I ended up cutting away too much and left gaps that weaken the floor channel to plywood fasteners by placing the clamps too close to the edge of the plywood. I recommend using appliance sized box cardboard mock up templates for end rounds to get it well centered and fully sized...

On my '73 trailer the frame spar crossmembers vary in height to allow for joining plate installation - an 8" wide plywood plate overlapping the joint by 4" each side and then both thicknesses through bolted into the spar so it really doesn't matter where the seam ends up...
The days are short and the night is long and the stars go tumbling by.. . ~Airstream~
Wabbiteer is offline   Reply With Quote
Old 05-06-2008, 07:11 AM   #3
3 Rivet Member
Ambie '64's Avatar
1964 28' Ambassador
Oklahoma City , Oklahoma
Join Date: Jan 2006
Posts: 143
For what it's worth, I've been doing a little researching on this problem and received this reply from Georgia-Pacific...

Dear Customer,
Georgia-Pacific does not manufacture material wider than 4' in a 5/8" thick panel 8' long. Another option would be marine-grade plywood which is available in 4x8-foot sheets of 1/4, 3/8, 1/2, 5/8 and 3/4-inch thickness. Sheets up to 5x12 feet are also available. Available grades are A-A, A-B, B-B (face-back), MDO and HDO. Marine-grade plywood is not treated with any chemicals to enhance its resistance to decay. If decay is a concern, it should be pressure-preservative treated to an appropriate standard.

The detailed description of veneer grades and Marine-grade plywood is contained in Voluntary Product Standard PS 1-95: Construction And Industrial Plywood.

Although Georgia-Pacific Corporation no longer manufactures marine grade plywood, a few building products companies still do (such as Plum Creek and Roseburg Forest Products). BlueLinx is the distributor for both and they stock both " and " panels. BlueLinx can be reached at 1-800-830-7370 (West Coast).

Thank you for contacting Georgia-Pacific.

I will continue to search for the optimum material for this application and update on my findings.
Ambie '64 is offline   Reply With Quote
Old 05-06-2008, 07:33 AM   #4
Rivet Master
drag'nwagon's Avatar
1974 31' Sovereign
1970 23' Safari
1956 26' Cruiser Overlander
Lambertville , Michigan
Join Date: Aug 2006
Posts: 1,174

I would not reccomend MDF for sub-floor, due to its tendency to swell once it gets wet,(and it will get wet). I did a fair amount of research on this very subject as I have some sections of floor to replace on my '56. If you are not going to finish the plywood than you do not need to spend $80.00/sheet for AA marine board. You can save your self a lot of $$ and at the same time install a great subfloor by using BCX board. The (X) is the glue (water resistant) that is used in marine grade plywood.
Operation "Save Rudy" Strike Team (charter member)

Yes, I am still working on it.
drag'nwagon is offline   Reply With Quote
Old 05-06-2008, 07:48 AM   #5
Rivet Master
InsideOut's Avatar

1956 22' Safari
Vintage Kin Owner
Conifer/Evergreen , Colorado
Join Date: Feb 2002
Posts: 12,130
Images: 108
We used 3/4" marine grade plywood on our '56. The reason we went with 3/4" instead of the 5/8" (actually 11/16" to match the original) was we took out is the old floor AND flooring which went under the c-channels and since we were doing a shell on installation and couldn't get the flooring under the channel with the wood. So to make-up the difference, we upped the plywd thickness.

I second the opinion to not use OSB or MDF...two reasons, 1) the water issue previously mentioned & 2) the additional weight. They are much heavier than plywood because of all the glue.

We did not need anything wider than 48"...the seams did not overlap in ours, the elevator bolts spanned the gap between the panels. When we did ours, we attached to the frame on both sides of the joint. the butt joints will be filled prior to installing our flooring.

To see some pics, check out:

Vintage Airstream Club - Past President 2007/2008
WBCCI #1824 - DenCO Unit Past President (2005)
AIR #30 - Join Date: 2-25-2002

RMVAC | WBCCI DenCO Unit | BIRDY - our 1956 Safari | 1964 Serro Scotty
InsideOut is offline   Reply With Quote
Old 05-06-2008, 08:34 AM   #6
3 Rivet Member
Ambie '64's Avatar
1964 28' Ambassador
Oklahoma City , Oklahoma
Join Date: Jan 2006
Posts: 143
I hear you on the MDF problem. I might have been mistaken in my first post regarding using MDF for the templates. I was using 4x8 sheets of a pegboard material (without the holes) that was 3/16" thick. They were very flimsy, but easily cut with a jigsaw. My c-channels were attached to the sub floor with the vinyl tiles butting up to the channel, so I'm pretty well locked into 5/8" thickness unless I want to play find-the-rivet-holes when the shell comes back down. Drag'n, thanks for the heads up on BCX. I was concerned not only with the cost of marine ply, but also the weight. I'm somewhat amused with this little conundrum, since it seems that there are few Ambassadors needing a sub floor out there!
Ambie '64 is offline   Reply With Quote
Old 05-07-2008, 05:00 PM   #7
2 Rivet Member
crowldawg's Avatar
1966 20' Globetrotter
Orient , New York
Join Date: Sep 2007
Posts: 57
I only had to replace a small (20X72) section of the sub-floor .I used 5/8 CDX.Then I dash patched the seams and the voids with fiberglass impregnated Bondo
crowldawg is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
What's on top of the subfloor??? TitusLivy Repairing/Replacing Floor &/or Frame 3 01-14-2008 02:17 PM
Subfloor replacement grizz814 Repairing/Replacing Floor &/or Frame 6 09-20-2006 07:16 PM
subfloor for dummies mudmuffin Repairing/Replacing Floor &/or Frame 12 08-02-2006 10:03 PM
Subfloor Repair Steve Heywood Repairing/Replacing Floor &/or Frame 2 01-13-2006 07:10 PM
No subfloor? Over59 Repairing/Replacing Floor &/or Frame 5 05-13-2004 06:41 PM

Featured Campgrounds

Reviews provided by


This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.

All times are GMT -6. The time now is 08:35 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.