Floor Thickness

[Michele]

I am ready to buy the wood for my floor but I'm not sure what to use. I have been reading the forum all week but I haven't seen anything that really addresses my particular situation so forgive me for asking such a basic question. I'm building a standie similar to Steve's Puffin (6.5 X 11) on an old pop-up frame. I will be bolting the floor directly to the frame. There seems to be plenty of support beams so I would like to know what is the thinnest wood I can use as over-all height is a major concern. Here are some pics of my frame:

[goldcoop]

Michele-

Since we are talking a floor bigger than a 4' x 8' sheet of ply....

On the Aliner I'm currently working on, I used 3/8" CDX ply bolted to my frame and then fully glued & laminated 1/4" underlayment ply on top of that, making sure to stagger the joints; and finished off with sheet Vinyl flooring.

Undercoat the bottom side as customary with "roofing tar".

Hope this helps?

Cheers,

Coop

[Steve_Cox]

Hi Michele,

I was just reading a thread about that subject this morning about the floor in a Widget, which is about the same floor dimension you are using. The general consensus was 1/2" plywood, which is almost what Coop said.

[Miriam C.]

Coop's got it. The 1/4" overlay will keep you from having to "join' the plywood at the edge.

A trick for the "evil smelling black goo" is to pour it on and spread it out with a Dollar store squeegee. Less mess. And wear very old clothes and gloves. It tends to get where you want it the least. Let it dry for a day and with gloves on flip it over. Some help is useful here.

[Michele]

I intend to extend the floor out over the frame like Steve did on his Puffin.

The frame is 6 feet 3 inches and I intend to make the floor 6 feet 8 inches which is the way it was when it was a pop-up. Will 1/2 plywood be strong enough to support the weight of the walls?

[angib]

Everyone tends to assume that the walls are held up by the floor, but on a teardrop that isn't necessarily true, once the body is assembled.

That photo of Steve's Puffin is an excellent example. While he was building it, sure, the walls were held up by the floor, particularly at the stage where there was only a floor and two side walls.

However, once complete that front wall and its twin at the back are sitting right on the frame and are way, waaaay stronger than the floor which is just a trampoline by comparison. You must all have played that game at school with holding a ruler flat and seeing how much it can carry and then doing the same with it vertical, when it can carry much, much more (maybe 10 times as much).

So what Steve needed was a good connection between the sides and the front/back (I see lots of screws into a wood fillet inside - perfect) and then a good connection between the front/back and the frame.

Most teardrops don't have a back wall, but they have something better, a galley bulkhead - that always crosses the frame (providing a strong support), so then the only need is to connect the front wall to the trailer frame.

Now..... all this changes if the body overhangs the frame lengthways as well as widthways. By overhang, I mean 6" or 12", not an inch or two. Then we have got the body held up by the trampoline floor, so lots of extra strength would then be required in the floor.

So Michele, the question is will your front and back walls be supported on/close to the frame - if so, just an unframed ply floor will do.

Andrew

[Michele]

Wow Andrew, thank you so much for this response. This explaination has helped me tremendously in understanding the building process. I was going to overhang the front by 5 inches and the back by 3 inches. But after reading your post, now I'm not sure. The only reason I was going to overhang the sides was because that is the way the floor was originally and I thought I needed to do that in order to clear the wheel well. I didn't want the strip of wood on the other side of the wheel to be too thin, see pic:

I don't need the extra width on the trailer, but I do need the extra length on both ends so now I'm not sure what to do as I have already purchased and cut the 1/2 plywood.

[madjack]

Michelle, as long as your front and rear bulkheads are over the frame, you should be good to go...the bulkhead can be the wall at the foot of the sleeping area or what have you, as long as you have a couple of bulkheads(front and rear) over the frame, you can extend out from them.....
madjack

[angib]

I can't see it matters how wide that strip alongside the wheel is - zero would also be fine.

Andrew

PS Homeless man curses are a much bigger risk than overhangs. However you know you did right by him, so his curses should be harmless......

[bdosborn]

I would throw the 1/2" over your frame and see how well it holds you up. I added quite a bit of bracing after walking on the sheathing while it was sitting on only the frame. I found that 16" is about the most you can span with 1/2" acx and not have it crackle when you walk on it.



Bruce

[Michele]

Ok, now Bruce's comment has me really confused. I definately have spots in my frame that are more than 16" where there will be no frame underneath for support. I cannot have a subfloor because of the height issue. Does that mean I am going to fall through the floor where it is unsupported by the frame?

[bobhenry]

At 24"o/c 1/2" osb will deflect about 3/8 to 1/2 inch at 300 pounds per sq ft
You will not crush thru unless you are 725 lbs + and standing on 1 foot. If this is a standie use 5/8 or 3/4 but a tear is usually supporting only a mattress and a load that is not concentrated. 3/4 osb weighs only 34 pounds more than 7/16 so you are concerned about a load that weighs less than your 5 gallon water jug. I used 3/4 osb directly to the frame 2 layers of 3/4 foam and a floating floor of 7/16 osb. This is the foundation of your little house. Maybe I over built a bit but I can still pull the 5x10 across my driveway by hand. God I gotta get Chubby weighed not knowing is killing me.

[bdosborn]

Ok, now Bruce's comment has me really confused. I definately have spots in my frame that are more than 16" where there will be no frame underneath for support. I cannot have a subfloor because of the height issue. Does that mean I am going to fall through the floor where it is unsupported by the frame?

Extra support doesn't have to raise the floor. Just glue and screw some 2x2s to the area that is too bouncy. They don't have to sit on top of the trailer frame to stiffen up the floor, the can run in between the frame too.
Bruce

[jay]

and use construction adhesive at every opportunity

[Michele]

Thank you everyone for your responses. After hearing it would take 725 pounds to break through the floor I feel confident about using the 1/2 plywood. I used 2X6s ripped down to fit very snuggly inside the frame. They are screwed in at the ends. I needed the one in the back because I am extending the floor past the frame and I needed something to secure by back wall to. I realize that I have just added a lot of weight to my frame but my tow vehichle is a Jeep Liberty so weight is a consideration but not a big concern. Piece of mind was more important here and this was the best way I could think of the get a really solid connection.




Here's a shot of the whole floor but it is not attached yet because I still need to put the plastic wheel covers back in.