Floor Thickness

[TN_teardrop]

I am starting my first teardrop and have a couple of questions?

1. I want to insulate both my floor and my walls. Would 1/2" plywood with 2X4's sandwiched in the middle be good for the flooring? I want to use the 1 1/2" foam board for the insulation in the floor. Or would it be better if I took 3/4" with the 2X4's and 1/4" covering? Would the side walls be ok with two 1/2" plywood and 1x's sandwiched between so that 3/4" foam board could act as the insulation?

2. Would SPAR urethane be better to use than a Rino type of bedliner for the underside of the floor, or a combination of both?

3. Sorry, I know I said a couple, but...............Is it best to try to get air tight on the cabin of the teardrop? ie, caulk all seams. Or do you want it to be able to expand and contract do to the climate changes?


Thanks in advance.

[RandyG]

My floor is made of 1/2" but I don't see the point insulating it since there will be a foam mattress on top of it, unless you plan on camping in -20 temps. If you do insulate then I would put the 1/2" with foam under it, then some flex seal or some other type of liner on the bottom of the foam. What type of wall - floor joint are you planning? Building the insulation into the frame will give more interior height depending on that joint.

[citylights]

I am starting my first teardrop and have a couple of questions?
1. I want to insulate both my floor and my walls. Would 1/2" plywood with 2X4's sandwiched in the middle be good for the flooring? I want to use the 1 1/2" foam board for the insulation in the floor. Or would it be better if I took 3/4" with the 2X4's and 1/4" covering? Would the side walls be ok with two 1/2" plywood and 1x's sandwiched between so that 3/4" foam board could act as the insulation?
2. Would SPAR urethane be better to use than a Rino type of bedliner for the underside of the floor, or a combination of both?
3. Sorry, I know I said a couple, but...............Is it best to try to get air tight on the cabin of the teardrop? ie, caulk all seams. Or do you want it to be able to expand and contract do to the climate changes?
Thanks in advance.

Woa there. Like most new to this, you are suggesting serious overbuild!

1. Most go with 1x2 laid flat on the trailer frame with 1/2 inch plywood over that. If you want to insulate, cut one inch insulating foam board and glue into the one inch frame. (Mine is overbuilt, I used 3/4 plywood, non-insulated.). Non insulated side walls are usually 1/2 inch plywood, some at 3/4 inch plywood. Insulated is usually a 1/4 inch skin, anything 1/2 to 1 inch foam insulation, and a 1/4 inch Inside skin. (Again, I overbuilt, 3/4 inch plywood walls, non insulated.)

2. Most recommend black goopy roof tar for the underside of the tear. That is a long lasting water repelling sealant and wood preservative. Do it right one and never worry about it again. (I used truck bed liner paint. Get the brush on type, the rattle can stuff doesn't go far enough. I figure I will have to repaint or touch up about every 5 years.)

3. Most go for air tight glue and screw construction. Air tight is also water proof which is the big deal. Some put a permanent air vent somewhere to prevent suffocation. Others rely on knowing that they need a window or roof top vent cracked open when they are inside.

When I talk about a over built... A tear should weigh in the 750 a 1250 lb range to be towed by a car. I wasn't too worried about light weight construction because I was going to tow with a truck and built a little heavy for offroad use. I used 3/4 ply and a lot of 2x2 spars... And some other heavy stuff I won't mention, and I think my tear is in the 1750 lb range. (I really need to take it down and get an official weight!). Anyway, that pretty much rules out towing with a car, and now I am stuck pulling all that extra weight that wasn't really needed.

My advice is build smart, not heavy. Torsion box or laminated sandwich design is really light weight and strong.

[linuxmanxxx]

I've built all my floors and walls with 1x2 framing and 3/4 foam and good glue makes it massively strong and light. Floor might be better with 1x4 outer framing to give wider area for attaching walls and anything interior to. And I've always used the 5mm luan/undrrlayment on moat sides and have put both frp and aluminum over the outside. Roof you flip the 1x2 up and down and double your 3/4 to match the 1.5" height. A lesson learned has been always build your roof sandwich both sides before attaching or if you do bottom and attach and then skin the top you have to prop it up underneath till the glue sets or you sag in the center.

[aggie79]

I used 1x2s to frame the floor. At the ends 1x3s. For plywood, I used 1/4" top and bottom. This assembly is plenty strong. 1/8" plywood probably would have been sufficient.

This is a picture of the framing being glued to the bottom plywood deck.



This shows the insulation being installed.



This is a section of the finished floor. I built the floor "long" and then trimmed it to length. The MDF board on top is a guide for my skill saw that I used to cut the angle to match the front curve of my profile.



Take care,
Tom

[Campin' Texan]

I over built my a little as well, 5'x10', 3/4" walls and floor. But I wasn't too concerned about the weight. Even then, it still weighed in at only 1200 lbs.

I built my floor with a 2x2 frame and 3/4" plywood. I used 2x2s because of the way I mounted my walls. I coated everything with epoxy. The underside got a coat of rubberized automotive paint. Then I glued 1/2" foam board insulation to the bottom. The insulation will keep you warmer, and it will prevent condensation on the inside. Many people have had issues with condensation and woke up to wet mattresses. I insulated the ceiling, but not the walls.

[Woodbutcher]

My first teardrop floor was a 2x4 flat with 1/2" top and bottom. I used 1 1/2" ridged insulation in between. Teardrop #2 had a 3/4" floor no insulation. Teardrop #3 had a 1/2" floor, no insulation. Each trailer got lighter as I went. I don't believe I would ever insulate a floor again. My suggestion would be, build without any insulation. If for some reason you want it, pull the mattress out and add in the ridged foam between the floor and the mattress. Put the mattress on top without another layer of wood. My first teardrop was fully insulated with wood inside and out, and weighed 1800 lbs. The third one has no insulation and weighs about 800lbs. It has only 1/4" plywood over a frame work skeleton. Number one and three have both been used in weather below freezing with no issues. I just added an extra blanket, when I did not have shore power to run my small heater.

[KCStudly]

Woodbutcher, I just love it when ever you post a pic of the Slow Mobile. That thing is art!

[crazycyclist]

I agree that there is no need for insulation in the floor. Its a lot of work and weight for minimal benefit.

Keep in mind that the strength of the floor will be provided by the steel trailer frame. I chose to use 1x2 for framing the underside floor just go give a better attachment point. Then I bolted the floor to the frame using elevator bolts from Fastenal. I counter sunk the holes using a forester bit so the heads would be flush. The floor is going nowhere.

[Campin' Texan]

I agree that there is no need for insulation in the floor. Its a lot of work and weight for minimal benefit.

I have to disagree with this. I think it's worth it because it's very easy to install and adds almost no weight. Cut the foam board and glue it to the bottom.

[crazycyclist]

Cut the foam board and glue it to the bottom.

The downside of this is that you now have a place for moisture and road grime to be trapped unless you seal it very well.

The beauty of building teardrops is we can each look at the options and choose our own design!

[Campin' Texan]

The beauty of building teardrops is we can each look at the options and choose our own design!

[madjack]

...what you are suggesting is massive overkill...I used 1/2"ply on for the floor, placed directly on the trailer frame...since I had epoxy on hand, I coated with 2 coats and while I didn't insulate the floor at first, I went back later and placed a 1/2 piece of blue foam under my mattress which took care of condensate problem on the floor...my walls are just 3/4 ply and that works fine for me...if stick framing your walls, 1/4" or even 1/8 is sufficient, using 1x2 for framing material...good luck, have fun and don't forget the pics...we luv da pics, doanchano......
madjack

[jonw]

I've got a 3/4in. marine ply floor with no insulation. With an air mattress in cold weather we were cold so we added a sheet of foam carpet insulation on top of the floor with a piece of carpeting on top of that - much improved.

The air mattress was too bouncy so now we use a 3 in. memory foam mattress topper on top of the carpet and are quite comfy even in sub-freezing weather.

[linuxmanxxx]

Go study the sandwich method also known as torsion box method. Using simple 5mm on both sides and glue will yield 30% of the weight of 3/4 plywood or mdf and much more rigid as well. Windd up little over 1" thick and strong enough to walk on. Less weight insulated and stronger it's a triple win