Sub-floor Done!

Early yesterday I went to Lowes and got the redwood and hardware for the sub-floor.  I started by laying out the 16 footers that run the length of the trailer.  I also bought five 8 footers that were to run the width of the trailer underneath the steel chassis.  It was how I planned to accomplish the width I wanted for the sub-floor out past the side rails of the trailer.  While I was hard at work, my dad and younger brother were working on re-building an ATV motor.  Out of curiosity, my dad came poking about my project.  I could tell he was impressed and started getting excited about the  project.  As I started running through the design, layout and build sequence my dad, a builder of 40 years, came up with a whole host of suggestions.


Firstly, I wasn't going to need the horizontal redwood planks to achieve the width I wanted.  So long as I use an 1 1/2" tongue and groove (which is rated structural) on the floors, I can cantilever them out over my last joist to achieve my width.  Together we sketched a design detail on how to cap the end of the t&g.  This suggestion alone saved me the weight of five 8' 2x4's, the labor to install them, 3.5" of ground clearance, a hell of a lot of sealing (all of these 2x4's in the undercarriage would have needed a durable, water-proof finish) and $60 in materials.


Secondly, I intended to run strips of 1/4" plywood between the joists to lay my fiberglass on.  These would have needed to be sealed from underneath and the bottoms of the 16 foot 2x4's would have needed sealing as well.  Furthermore, being as there was a 5/8" different in height between the tops of the 4" C-Channel and the 3" cross-members, I intended to cut mortises (by hand) in the bottom of the 2x4's wherever they crossed 4" channel, that way they all sat flat against the frame and level.


My dad suggested that instead of notching the 2x4's, I should just run spacers wherever the 2x4's rest on low-spots in the chassis rails.  We measured the difference - 5/8".  Low and behold my dad had a sheet of 5/8" OSB in the shop, so I through the width gauge on the circ. saw and ripped a bunch of 1.5" wide furring strips, and adhered them to the frame.


Furthermore, instead of using a thin plywood that would need sealing and leaving the bottoms of my joists exposed to the road, he suggested I apply a thin, heavy-duty, water-proof material to the trailer before placing the joists.  We crawled under the fifth wheel travel trailer (which you can see in the background of the pic below) and sure enough, it was dried in with felt tar paper, like used for roofing.  So I ran to Home Desperate and got a roll of tar paper for $17.  This suggestion saved me a boatload of money, better sealed the bottom of my chassis and weighs considerably less than the plywood would have.

In the pic above you can see half of the tar paper in place and the OSB furring strips underneath the 2x4's in the right of the photo.

In the above pic, we have all of the tar paper rolled out and the 2x4 joists in place.  We then drilled a bunch of holes, first 1" openings about an 1" deep to countersink the lag bolts then 3/8" holes the rest of the way through the joists, furring strips and into the frame channel below.  Jeffrey then crawled around under the trailer, affixing the nuts and washers and wrenching them while I ratcheted them tight from above.  Below is an above shot of the countersunk holes with hardware in place.

With the tar paper and joists in place, I crawled under the trailer and fastened furring strips to the bottoms of the joists between the frame rails to help hold the tar paper up.  Below is a picture from under the trailer.  All of these furring strips will need to be sealed.  I'll probably use a roll on chassis liner, which will also add durability to the tar paper.

Up next, I need to roll fiberglass batting into the floor joists for insulation and run my t&g flooring over top.  Because I have some leftover tar paper, I'll probably use another layer of it over the glass before the floors go down.


My dad also gave me some good suggestions for my interior walls and a plan of attack for leaving my mahogany t&g exposed on the sides of the vardo but I'll cover those when I get to them.


It's coming right along!