Step 3: Build the floor

[mikeschn]

Step 3: Build your floor ½” fir plywood
(Revised 10-May-2005 to allow for sidewalls to cover trailer frame)

The floor is built from 2 sheets of 5’x5’x1/2” Baltic birch., and xx 1x2s. Cut both sheets of Baltic birch to 48” x 58 ½. Place the two sheets together on a flat surface, so that you end up with a rectangle 96”x58 ½”. (The trailer is 58” x 96”. The floor should hang over the trailer by about ¼” on each side.

Using Gorilla glue /polyurethane glue, and 1 ¼” stainless steel screws, glue and screw the first 8’ long piece of 1x2 to the long edge of the floor.

Glue and screw the (5) 55 ½” subfloor studs to the plywood as shown in the drawing below.



Here's a pdf of that drawing...
http://www.mikenchell.com/images/subfloor.pdf

Glue and screw the last 8’ long piece of 1x2. Let the glue dry overnight.

The floor can be uninsulated for 3 seasons camping, or insulated for 4 seasons camping. If you decide to insulate, cut the ¾” extruded polystyrene on the table saw to fit into the floor recesses. Have all 4 pieces prepared before coating the floor with roof tar.

Use roof tar to coat the underside of the floor, making sure not to get any tar on the sides where the walls will be attached.

Press the EPS into the wet tar and screw the EPS into the recesses with 1 ¼” stainless steel panhead screws and fender washers. Use about 12 screws per panel. Let dry. Drying could take several days or more, depending on the temperature.

The stainless steel hardware is used because it has a fine thread and a controlled length, to help prevent you from breaking thru the floor. (If you break thru the floor, remove that screw, grind off the tip, and screw it back in.)

Bolt the floor to the trailer with 3/8” bolts, (5) bolts per side. Use flat washers and nylock nuts.

[toypusher]

Mike,

It may be overkill, but how about a spline and gorilla glue the two halves of plywood together? Or do you think that is too much for a beginner?

Kerry

[TomS]

Mike, A couple of details on the floor specific to the Red Trailer.

1. There are some bolt heads in the top of the frame where the cross members meet the side rails. In order for the frame to sit flush with the top of the frame relief holes need to be cut for these bolt heads.

a. Clamp the frame in place.

b. tap the frame with a rubber mallet or a hammer and block of wood at each of these bolt heads to make a shallow impression of the bolt head in the bottom of the frame.

c. Cut a shallow relief holes for each bolt using a Forstner bit. Use a spare bolt to check for adequate depth.

2. The Red Trailer frame comes with predrilled mounting holes for mounting a plywood deck. Builders can save themselves a lot of drilling by utilizing these holes. Here's what I did:

a. After cutting the relief holes mentioned above and before coating the underside of the floor, place the the floor in position on the frame.

b. Take a 3/8" mounting bolt and dip one end in the roofing asphalt. Crawl under the trailer and locate your first mounting hole. Pass the bolt through the mounting hole and press the wet bolt firmly against the floor assembly. This will leave a perfect black mark showing the exact location of the mounting hole. Repeat with all the other mounting holes. It's nice to have a helper for this step.

c. Remove the floor assemply from the frame. Use the marks left by the wet bolt to drill your mounting holes. Counter sink the other side using a Forstner bit large enough to accomodate the bolt and the socket you plan to use when mounting the floor.

d. After mounting the floor, fill in the counter sinks for the mounting holes with wood filler.

Here's a couple of other details I noticed.

Why cut the insulation on a table saw? Wouldn't that make an awful mess. With the static electricity generated, I picture thousands of tiny particles sticking to everything in sight. I don't know if there are any adverse health effects from inhaling foam particles. But, I don't want to give the Medical folks and opportunity to find out. This stuff cuts very easily with a simple box cutter and a straight edge.

Also, why use Baltic birch for the floor. You're only going to cover it up. ACX ply is cheaper and easier to find.

Just my $.02 worth (Thats $.03 for you Canadians and $.20 for Kai down in Mexico ;-)

[backwoodsman]

Glue and screw the (5) 55 ½” subfloor studs to the plywood as shown in the drawing below. (drawing forthcoming)

Glue and screw the last 8’ long piece of 1x2. Let the glue dry overnight.

Mike-

Please submit the drawings, I'm unclear on what you mean by this.

Thanks,

Greg

[JunkMan]

Why cut the insulation on a table saw? Wouldn't that make an awful mess. With the static electricity generated, I picture thousands of tiny particles sticking to everything in sight. I don't know if there are any adverse health effects from inhaling foam particles. But, I don't want to give the Medical folks and opportunity to find out. This stuff cuts very easily with a simple box cutter and a straight edge.

Tom,

I have cut tons of this stuff on the table saw, and it doesn't make as much of a mess as you would think, not much worse than sawdust. The advantage is that it leaves perfect edges. If your measurments are correct, and everything ids square, this stuff will fit like it was poured in if you ues a table saw. I have tried several other ways to cut this stuff, and nothing I have tried cuts as clean or works as nice as a table saw.

I am using foil covered foam on my trailer (more R value), not sure what the name of it is, but it isn't the bead type foam. It cuts real nice with a sharp utility knife and a straight edge.

[backwoodsman]

Has anybody lined the bottom of the trailer with aluminum?
I am planning on using a sheet of aluminum instead of the black tar bed-liner stuff. I'm going to have plenty left over after skinning the sides & top.
Pros? Cons?

Thanks,

Greg

[SteveH]

Greg,

I'm certainly no authority, but would think even if you covered it, you should also seal the wood, maybe even a better job than if it wasn't covered, because of the possibility of moisture getting into the wood thru seams/joints and not being able to get out, or down.

I can tell you the Camp-Inn I saw last weekend is a plywood floor with some sort of sealer on it, like varnish or something. The roofing tar/emulsion that a lot of us have used looks to be a much better sealing agent, and it's cheap. The only bad things are it stinks while putting it on and curing and it's pretty nasty if you get it on ya.

[mikeschn]

Glue and screw the (5) 55 ½” subfloor studs to the plywood as shown in the drawing below. (drawing forthcoming)

Glue and screw the last 8’ long piece of 1x2. Let the glue dry overnight.

Mike-

Please submit the drawings, I'm unclear on what you mean by this.

Thanks,

Greg

Hey Guys,

Sorry the drawings are taking so long... I am trying to learn a new cad package (the one that angib uses) so that I can make clear PDFs. My solid modeling package doesn't do drawings very well.

But I have a 4 day weekend, I'll be doing some studying... and maybe I can even crank out a drawing or two.

Mike...

PS. AmyH, how do you make your illustrations?

[mikeschn]

Mike-

Please submit the drawings, I'm unclear on what you mean by this.

Thanks,

Greg

Hey Greg,

I put the drawing up just now... Hope that helps... (It's in the first message in this thread)

Mike...

[backwoodsman]

Step 3: Build your floor ½” fir plywood
(Revised 10-May-2005 to allow for sidewalls to cover trailer frame)

The floor is built from 2 sheets of 5’x5’x1/2” Baltic birch., and xx 1x2s. Cut both sheets of Baltic birch to 48” x 58 ½. Place the two sheets together on a flat surface, so that you end up with a rectangle 96”x58 ½”. (The trailer is 58” x 96”. The floor should hang over the trailer by about ¼” on each side.

Mike,

Why do you hang the floor over 1/4" on the edges? I was thinking of making mine flush using the full 5' width of the plywood. (I am not using the red trailer, I'm going to weld my own)
What gives?
Thanks,
Greg

[mikeschn]

The 1/4" overhang is to allow for inaccuracies in the trailer, and to allow the wall to bolt up flush with the subfloor/floor.

You could indeed make it flush with the trailer. But you have to ensure that it is flush and that the trailer doesn't protrude out past the floor. If it does, you'll have a hard time getting your walls to stay vertical.

Mike...

[Mitheral]

Also, why use Baltic birch for the floor. You're only going to cover it up. ACX ply is cheaper and easier to find.

Advantages of Baltic Birch:
1) Comes in 5'X5' sizes. Less waste.
2) Twice as many layers, stronger product.
3) No internal voids, stronger product.

The extra laminations make it worth it all by it's self; the lack of voids will make it less likely to delam from moisture.

[asianflava]

Advantages of Baltic Birch:
1) Comes in 5'X5' sizes. Less waste.
2) Twice as many layers, stronger product.
3) No internal voids, stronger product.

Mine was actually 60 1/8 in. I used glued up panels for my cabinetry, I never cut the ends which insured that they would be the same length and parallel.

[Mitheral]

Mine was actually 60 1/8 in. I used glued up panels for my cabinetry, I never cut the ends which insured that they would be the same length and parallel.

Thats cool, one free saw cut.

[bledsoe3]

Mitheral, Are you building the generic Benroy. If so, where are you at on it?