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Need Help With Composite Walls

PostPosted: Tue Feb 09, 2010 6:55 pm
by dh
I'm going with composite walls, a 3/4" plywood core, cut out to a skeleton, 1/4" outside skin, and want to use wood panneling on the inside. Can I get away with 1/8" panneling on the walls? I found some stuff I like, and I can get it in either 1/4" or 1/8", at first I was thinking about 1/4" on the walls, and 1/8" on the celing, but it would shave a few lbs going 1/8" all around.

Also, are thier any general guildlines on the "Skeleton" center core? Besides putting wood where cabinets, doors, etc. will attach, how big and how far apart on the ribs?

PostPosted: Tue Feb 09, 2010 7:08 pm
by mikeschn
I do think you can go with 1/8" skins both inside and outside.

My only question is, are you going to fill the walls with insulation? What kind? Because 3/4" plywood is only 23/32" but 3/4" EPS insulation is 24/32". :?

You could even do 1/8" on the roof skin, if you put an additional 1/8" layer on the front of the teardrop to act as a rock guard.

Mike...

PostPosted: Tue Feb 09, 2010 7:50 pm
by Ageless
Mike; all it takes is some thin cardboard. Give it a coat of varnish and use it as a shim

PostPosted: Tue Feb 09, 2010 10:06 pm
by wannabefree
My walls are build exactly as you describe. No problems, just be sure you have backing wherever you want to attach something on the inside. That was not always the case for me. :oops:

PostPosted: Wed Feb 10, 2010 9:55 am
by aggie79
My walls are built similar to what you are thinking. For the interior, I used 5/16" thick engineered flooring, which is way overkill for strength (but it was the look I was going for and I didn't have to finish the wood which I really don't care for.)

As far as insulation, the white bead-type board will compress more easily than the blue or pink insulation so you won't have to worry about the difference in thicknesses between the insulation and your plywood framing.

I did allow about 4" width of the plywood "ribs" to for attachment of the floor, roof, bulkheads, cabinets, fenders, etc., but this dimension can be reduce to 2" or even 1 1/2" if you are pretty accurate with the location of these.

Image

My roof is a 1/8" ply, 1 1/2" framing and insulation, and 1/8" ply sandwich, and it is heck for stout. Everything is adhered with PL Premium. Once the glues sets, there is very little deflection in the 1/8" plywood.

Tom

PostPosted: Wed Feb 10, 2010 6:55 pm
by dh
mikeschn wrote:I do think you can go with 1/8" skins both inside and outside.

My only question is, are you going to fill the walls with insulation? What kind? Because 3/4" plywood is only 23/32" but 3/4" EPS insulation is 24/32". :?

You could even do 1/8" on the roof skin, if you put an additional 1/8" layer on the front of the teardrop to act as a rock guard.

Mike...


Alreayd a step ahead on this one, I have a neighbor who is the high school shop teacher. Run the foam through the surface sander, and it quickly makes it however thick I want it.

PostPosted: Wed Feb 10, 2010 7:34 pm
by mikeschn
dh wrote:
mikeschn wrote:I do think you can go with 1/8" skins both inside and outside.

My only question is, are you going to fill the walls with insulation? What kind? Because 3/4" plywood is only 23/32" but 3/4" EPS insulation is 24/32". :?

You could even do 1/8" on the roof skin, if you put an additional 1/8" layer on the front of the teardrop to act as a rock guard.

Mike...


Alreayd a step ahead on this one, I have a neighbor who is the high school shop teacher. Run the foam through the surface sander, and it quickly makes it however thick I want it.


I don't have one of them surface sander thingies... Hmmmm.... :oops:

Mike...

PostPosted: Wed Feb 10, 2010 9:12 pm
by bbarry
mikeschn wrote:I do think you can go with 1/8" skins both inside and outside.

My only question is, are you going to fill the walls with insulation? What kind? Because 3/4" plywood is only 23/32" but 3/4" EPS insulation is 24/32". :?

You could even do 1/8" on the roof skin, if you put an additional 1/8" layer on the front of the teardrop to act as a rock guard.

Mike...


It's probably redundant to agree with Mike as he has about 1500% more experience than I, but I did exactly as you described except with 1/8" ply for both skins, as Mike suggests. It's much sturdier than you might expect once you epoxy it to the frame. There is virtually no give in the skin between the framing.

PostPosted: Wed Feb 10, 2010 11:53 pm
by dh
mikeschn wrote:
dh wrote:
mikeschn wrote:I do think you can go with 1/8" skins both inside and outside.

My only question is, are you going to fill the walls with insulation? What kind? Because 3/4" plywood is only 23/32" but 3/4" EPS insulation is 24/32". :?

You could even do 1/8" on the roof skin, if you put an additional 1/8" layer on the front of the teardrop to act as a rock guard.

Mike...


Alreayd a step ahead on this one, I have a neighbor who is the high school shop teacher. Run the foam through the surface sander, and it quickly makes it however thick I want it.


I don't have one of them surface sander thingies... Hmmmm.... :oops:

Mike...


Its like a big belt sander, but it is set up like a planer, so you set the height and feed the wood(er, foam) through.

PostPosted: Thu Feb 11, 2010 2:29 am
by afreegreek
a house is built using 2x4 or 2x6 studs spaced at 16 or 24 inches, held in place between the plates with two 3-1/4 inch nails top and bottom and sheeted with 1/2 OSB nailed every 4 inches around the perimeter and 6 inches in the field. no epoxy, no glue no screws. this will hold the weight of the second floor, another wall and the entire roof plus a snow load and all your stuff..

'cmon people, it's a 4x8 trailer for christ's sake. step away from the glue, the fumes are getting to you.. :?

PostPosted: Thu Feb 11, 2010 5:08 am
by bobhenry
afreegreek wrote:a house is built using 2x4 or 2x6 studs spaced at 16 or 24 inches, held in place between the plates with two 3-1/4 inch nails top and bottom and sheeted with 1/2 OSB nailed every 4 inches around the perimeter and 6 inches in the field. no epoxy, no glue no screws. this will hold the weight of the second floor, another wall and the entire roof plus a snow load and all your stuff..

'cmon people, it's a 4x8 trailer for christ's sake. step away from the glue, the fumes are getting to you.. :?


And your house is not experiencing sustained winds of 60 - 70 MPH on a daily basis for hours and hours at a time. It does not endure the torsional twist of cornering or the torsional flex of frame flex. Very seldom will your home experience impact load and the uplift stress of sustained high winds.

It's not a house It's is a Different critter. I built "Barn to be wild" just as you have described

Image

Yet I GLUED and screwed each connection. Let in wind bracing was used to triangulate all corners for wind shear reinforcement. Each wall cavity is stuffed with 3/4 blue foam to further aid the 3/8 " outside skin in preventing wind racking of the walls. Don't over simplify your little 4x8 / 5 x 10 box it is doing a lot of things and every help you can give it will pay off in extended life and a lot more fun.

PostPosted: Thu Feb 11, 2010 7:13 am
by bobhenry
in the past 25 + years, about the only thing I haven't built is a tear drop trailer so I know a thing or two about how stuff is made

You said a bunch there ! :o

In the past 10 I have been responsible fo 4070 residential homes a dozen 3 -4 story hotels a few health centers and 30 - 40 commercial strip malls. As near as I know they are all still standing.

As a hobby a couple hundred mini barns and garages and I have 2 tears and a couple tiny trailers under my belt but perhaps I should defer to your vast experience
EVEN THOUGH YOU NEVER BUILT A TEARDROP :roll:

PostPosted: Thu Feb 11, 2010 7:25 am
by TonyT
Bob,

I'll have to agree, While driving down the interstate I would rather worry about finding a good radio station and not if parts are flying off my trailer.

Tony

PostPosted: Thu Feb 11, 2010 8:30 am
by afreegreek
bobhenry wrote:in the past 25 + years, about the only thing I haven't built is a tear drop trailer so I know a thing or two about how stuff is made

You said a bunch there ! :o

In the past 10 I have been responsible fo 4070 residential homes a dozen 3 -4 story hotels a few health centers and 30 - 40 commercial strip malls. As near as I know they are all still standing.

As a hobby a couple hundred mini barns and garages and I have 2 tears and a couple tiny trailers under my belt but perhaps I should defer to your vast experience
EVEN THOUGH YOU NEVER BUILT A TEARDROP :roll:
built anything that flies or floats? I have. here's a pic of the project I'm working on now..

I've built wood, aluminum and fibreglass yachts, carbon fibre masts, a wood frame airplane, a dozen kayaks and canoes. wood bicycle rims, a few travel trailers and a few thousand pieces of furniture/millwork.. so yeah, I've built a few things.

BTW, you can overbuild a mall and all will be well. over build a boat and it sinks, over build a plane and it won't get off the ground. the point is not what you can add, the point is what you can take away. Image

PostPosted: Thu Feb 11, 2010 8:34 am
by afreegreek
ouch huh?