Hands On: Wicked Choices


Preparing a sub floor (from an unrelated restoration)

Preparing a subfloor (photo from an unrelated restoration)

We have three weeks to get the sub floor in before the Spartan gets towed to Newhall to meet with the Nomads  on November 6th. (see Sam’s post 3)  So much to do!  Sam is scraping off all the old rust off the chassis.  Then he’ll use POR15, a product that forms a protective coating by bonding with rusty metal.  There is nothing green about this product.  The other option was to remove the trailer skin and transport it to Van Nuys for sand-blasting and powder coating.

Meanwhile, we have to search for suppliers for the sub floor lumber, floor insulation, belly pan and grey water tanks.

Lumber Many, if not most, vintage trailers have rotting floors from water damage due to leaks from windows, metal seams, ceiling vents and

Bathroom floor was rotted from leaks

plumbing. Then there’s the vapor that forms under the floor and walls.  After 60 years, the Spartan had all of the above.  The sub floor was rotted and had to go.  But replacing a trailer’s sub floor (all or part) can be a challenge.  Seems like there are as many ways to go about it as there are people willing to tackle the job.

Marine grade plywood is worth the extra expense.

Sam has already cleared out the trailer and has a clean slate.  He’ll use 3/4″ marine grade plywood.  We’d like to use sustainable lumber.  But that brings up all kinds of issues about how you define “renewable” forests, where it comes from and how much energy is consumed with transport.  (See Treehugger links below)                                                  For the subfloor we will use marine grade 3/4″ lumber.  Unlike the cheaper variety, marine grade comes from the U.S.  (In either case, the glue used to make plywood apparently no longer has formaldehyde in it.)

Belly Pan We want a more sturdy belly pan that the conventional MDF or plywood variety that always seem to get damaged from scrapes or rot aways.  Aluminum will also keep out pests.   The thickness: 0.40 or 5053.  Another expense!

Sub-floor material and insulation

 Sam is supposed to refer to the link below for instructions on the sub-floor installation.   http://www.vintageairstream.com/floyd/restoration/floor/floor.html

Flooring – We are either going to go with 3/4″ marine grade plywood or Nyloboard, made of recyled carpet fibres.  We are waiting to hear from the later to see if they will donate the product.  More on that later…


Fiberglass insulation was used under the floor of this restoration- may not the greenest choice but it is relatively cheap. .

There are other options. TRA Certification (Airstreams gets certified by them) suggested Eco Batt by Knauf which has some recycled content and it not supposed to off-gas.  Company site don’t seem to mention where the product is manufactured nor do they mention certifiable fair labor practices

Another solution is a 1.5″ layer of foam spray. A soy or castor oil based variety comes in a do-it-yourself kit. It has a high R value, seals everything in place and keeps bugs out.But it would require all the plumbing and electrical under the floor to be in place before the foam goes in.  How to do that before November 6th?  Sam is in class full-time and is rehearsing for two plays after-hours.

Another looks interesting:  Airstream is using a sheet of plastic on the belly pan then Refletix, which is also recommended by this Airstream forum.  Here is how one of the forum members used a similar product.

I have used Prodex, much the same as Reflectix throughout the whole 26′ restored Argosy. However, I have glued 1″x2″ urethane strips onto the sub floor underside. Cutting the Prodex by 3″ oversize I have overlapped it onto the frame members attaching it with 3M 5200 Fast Cure to the urethane strips and frame. Prodex has advertised “R” value of 14.7. Added air space between bubble foil and sub floor adds about two points in “R” value. I did the same thing in the walls using 1/2″x2″ urethane foam strips in order to create air space on booth sides. I have brought the Prodex along the ribs toward the inner skin trimming the excess 1/8″ high past the rib. This way the inner wall skins sealed the cut edges of Prodex. My 15000 BTU Carrier freezes me out at the lowest setting in 95+ degree direct sun. Thanks, “Boatdoc

Next up: the grey and black water tanks to go under the belly pan.

by the Spartan web lackey


Sustainable Lumber Standards:  Forest Stewardship Council (FSC) vs. Sustainable Forestry Initiative (Treehugger) http://www.treehugger.com/files/2009/03/fsc-vs-fsi.php

Credible Forest Certification http://credibleforestcertification.org/home/

Airstream restoration, including the subfloor: http://www.vintageairstream.com/floyd/restoration/floor/floor.html

Partial subfloor replacement:                 http://56spartan.blogspot.com/2010/08/starting-on-floor-repair.html

This entry was posted in Chassis and axels, Devil In Details, Hands On, Sub Floor. Bookmark the permalink.

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