Marine Grade Plywood or Coosa Board That is the Question

[Isuzusweet]

I installed the sheets in a few different ways, as the rear of my Moho would have been very difficult to do in one piece.
In the front I cut the sheets so that they met in the middle with a 3/4" half overlapping joint.
Cheers
Sidekick Tony

[Re-Pete]

Originally Posted by cole3444

Isuzusweet,
When you put your Coosa board down did you run the sheets like the old plywood was installed width wise. Saw where some were putting theirs length wise. The web site shows I have three cities in my area where I can pick it up the Coosa. Trying to redo my 71 Sovereign frame and the Coosa sounds like what I need to install since most of my wood will be fastened to the ribs so my flooring will float due to temp changes.

cole3444,
I know you directed this question to Tony, but maybe this will also help. I'm finally getting to the point of flooring installation. I've had my Coosa standing by since about this time last year.

Having measured it several times and in both directions. I've decided that my best path is to run my first piece (the front piece) side to side. It will span my spare tire void in my frame. The width of this first piece will be about 37". Then the rest of my pieces will run lengthwise, so they will side butt right down the middle. This way I can break them lengthwise conveniently on cross members so that I will not have any flying splices. I've even added multiple additional outriggers so that my floor channel and breaks all fall on top of my outriggers. I will use the best part of 7 sheets without much waste. I will post pictures when I'm finished.

[Re-Pete]

[QUOTE=skyguyscott;2291971


...Or from water intrusion around the wheel wells or the spot along the rear bumper that channels water directly to the edge of the plywood floor - a design flaw AS has never bothered to address for what? 50 years now. (Though some clever and industrious owners have engineered a solution shared in this forum)...[/QUOTE]


Greetings skyguyscott,
Any idea where I can read up on some of these fixes? Even though I'm installing Coosa, I'm trying to either avert known leaks or direct them to a harmless way out of the shell via drain ports (weep holes).

[cole3444]

Re-Pete,
No problem all help appreciated. Does your frame have a piece of steel that runs length wise down your frame, my 71 does not, see pic. Can you post a pic of yours.

[Shermy1987]

Originally Posted by skyguyscott

Surely you know that there are many, many other ways water will get to your subfloor besides leaks, don't you?

For instance, condensation on the windows (single pane, mostly, not very thermally efficient) or even on the walls (not very well insulated, and with thermal bridging from the aluminum ribs riveted directly to the aluminum outer shell, which is a highly conductive material.

Or from water intrusion around the wheel wells or the spot along the rear bumper that channels water directly to the edge of the plywood floor - a design flaw AS has never bothered to address for what? 50 years now. (Though some clever and industrious owners have engineered a solution shared in this forum)

Or how about water from the refrigerator, perhaps from condensation on the coils to leaks from liquid spills from the box, or defrosting ice, or from the vents -- regardless of the source, soft, rotting floors beneath the fridge are a common enough occurrence that knowledgeable inspectors search for them in assessing the condition of used coaches.

Or in the bathroom, especially if you have a wet bath. Or even if you don't. Rotting around the toilet, or the shower is another common problem area. That water didn't come from a leak in the shell or window seals.

Or perhaps a storm came up whilst you where away from the trailer and left a window or vent open and rain got to the floor before you could stop it.

Or perhaps a pipe burst before you could winterize, or during travel through a particularly cold area one night.

Perhaps there was some plumbing issue, an old solder joint gives out or a pex fitting starts to go.

Maybe fido and spot get a little too happy and spill their water every time they see you, or even more unfortunately, maybe you didn't open the door in time for them to go out.

Those are just a few ways water has and will get to your subfloor. Water is pretty insidious in that way.

So you can be super anal and store your AS trailer indoors, annually caulk every seam, Silkaflex every rivet, Valkum around every door and window, and walbernize and wax the shell twice a year -- and water will still find a way to rot your subfloor -- because it is plywood and water rots plywood.

So when you finally get around to dealing with your rotted floors, you can choose to replace the plywood with more plywood, and then go though the hassle and expense and pain and do it again every ten years or so -- or you can decide to fix it once and for all with Coosa.

How does that make one a fanatic?

If so, I want fanatics building my house, operating on my liver, replacing my transmission and packing my parachute.

Yes, the material cost of Coosa is higher than plywood, and much, much higher than cardboard. Note that the arguments in favor of using cardboard (price, ease of purchasing) are the same for using plywood, only more so. And the arguments against using cardboard (it is wholly unsuitable for the application) are ultimately the same for plywood. And given the time and hassle of the labor, it's cheaper in the long run to use Coosa and one less thing to worry about.

All these problems you mention. Yet my Airstream spent 30 years sitting in a field in Missouri completely neglected. After 30 years of sitting as a capsule of mold. The only floor rot was the all too common rear end separation. This can easily be prevented by keeping the rear of the trailer sealed and draining. There's more than one way to deal with Air Streams little flaw here.

These problems you seem to be mentioning.all seem to be issues you would get in a 40 year old Air Stream that has not been restored. With careful restoration, most can be rectified.

When I restored my Airstream, I added inspection points to view areas where the body meets the plywood. Funnily enough. I've never seen any evidence of water intrusion at any of them.

[Shermy1987]

The idea that a little water getting onto plywood will make it rot is absolutely ludicrous. It takes enough water, often enough to saturate the material and leave it wet on and off for many years. If you prevent this from happening, it wont rot.

[Shermy1987]

Originally Posted by Isuzusweet

I'll admit I'm not competent enough to keep my 37 year old Airstream waterproof. Between leaks around the A/C units, condensation, and a host of other avenues that water can find its way into my subfloor, I guess I'm a terrible owner.

Very glad to hear that you are the perfect Airstream owner. Must be nice to be awesome! Keep telling yourself that.

Cheers
Sidekick Tony

Have you ever considered changing your name to "Coosa Board Tony".

You seem to repeatedly attack anybody who doesn't think Coosa board is the greatest stuff in the world like they're personally insulting you!!! You also seem to think that anybody who doesn't install Coosa board has some kind of mental disability. Then you repeatedly make petty insults to throw fuel on the fire!!!

If I'm not mistaken, you live in one of the wettest places on earth? If this is the case, I don't think anybody would think that using Coosa would be a bad choice. But most people don't live in places like Washington State, Western Oregon or Canada. For many people who live in the drier parts of North America, Coosa board isn't their first choice and for good reason.

The origional question of Coosa or Plywood allows for opinions on both sides and should be a discussion about both. Not a who's right or who's wrong shouting match. When you start telling people they're stupid for a different opinion, you turn the discussion south.

[Re-Pete]

Originally Posted by cole3444

Re-Pete,
No problem all help appreciated. Does your frame have a piece of steel that runs length wise down your frame, my 71 does not, see pic. Can you post a pic of yours.

Hi Cole3444,

I do have metal supports in the middle, but I had to modify them in order to run my flooring lengthwise. If you weld or have access to someone who does, you could easily add some 1/8" steel C channel down the middle in between your cross members, providing it will not interfere with water tanks, etc. As a matter of fact, In my case my middle supports that run over the black and gray tanks are removable in order to install the tanks.

Here's the thing though. In my case my OEM subfloor, except for the first 36" over the spare tire storage, was one entirely continuous sheet of OSB. It was 22' long and the width of the frame, so my cross members were placed a bit random. If your frame originally had 8' long x 4' wide flooring on it then, isn't it already laid out for that? If that's the case, maybe that's the best way to proceed.

Here are some pictures, of my frame and some of the alterations I've done.

[skyguyscott]

RePete,

Apologies for the tardy response; busy week.

Here is a link to one of many on the forum regarding a fix to water intrusion at the rear bumper (with helpful pics):

http://www.airforums.com/forums/f456...te-184009.html

Give a shout of thanks to the OP. This one is fairly simple and involves installing some flashing under the rub rail.

Others have just tried to caulk or silkaflex around the joint, but with all the vibration, I think the flashing method would be more effective in the long run.

I also owe something of an apology to AS; earlier I stated that AS had not bothered to address this flaw for some 50 years. The flaw started with the new body style away from the whale tail in 1969. Evidently, according to the above post, AS did attempt a fix in 2012. Better late than never. I am not familiar with what AS did to fix the problem, nor how effective their fix was.

[cole3444]

Re-Pete,
Thanks for the pics, My son does most of my welding. I always wondered why Airstream did not do this on the earlier 70's models, my 71 and 72 did not have that added support. Did you double up on your outriggers or did your frame come that way. Looks like it would help stiffen the frame. I figured since mine is a frame off do it right one time and I want have to do it again being 62 years old my kids can worry with them latter haha.

[skyguyscott]

Originally Posted by Shermy1987

The idea that a little water getting onto plywood will make it rot is absolutely ludicrous. It takes enough water, often enough to saturate the material and leave it wet on and off for many years. If you prevent this from happening, it wont rot.

In my case, when I purchased my 1969 trailer in the early 2000s, both the front and rear floor were soft, along with the area inside the door.

Since I lived fairly close to JC, I spent a considerable sum to have the factory replace these sections of the floor. They used plywood.

Some 12 years later, the area of the floor by the door, under the fridge and around the right wheel well were also soft, evidently from undetected water intrusion in the part of the coach difficult to inspect.

Note that the added material cost of installing Coosa, in my case, in the first instance would have been cheaper than doing it twice with Plywood, not to mention the time and headache of it all.

For some, installing plywood may be the most cost effective choice, especially if they don't plan on keeping the trailer for a long time, or if they are confident they can keep abreast of any insidious water intrusion for the rest of their lives, including as they age and mobility starts to become an issue.

For me, spending a little extra in material costs to fix the problem once and for all is well worth it.

[Re-Pete]

Originally Posted by cole3444

Re-Pete,
Thanks for the pics, My son does most of my welding. I always wondered why Airstream did not do this on the earlier 70's models, my 71 and 72 did not have that added support. Did you double up on your outriggers or did your frame come that way. Looks like it would help stiffen the frame. I figured since mine is a frame off do it right one time and I want have to do it again being 62 years old my kids can worry with them latter haha.

So Cole 3444, you're just a Whipper Snapper! I remember 62. Ahh, the good ole days. Hahaha. I'm 67.

Glad to hear your son welds. It's good to have someone in the family that welds because it will really allow you to make your frame all that it can be.

To answer your question, I did add a bunch of outriggers, I began by replacing about 4. At the same time I replace a 4' section of frame tube on the rear Street side. BTW, if you are not using gantries you should definitely consider them.
https://photos.app.goo.gl/K1H4XxdL4vpHzh3z5

At that point I was not welding, but I hired someone to do it for me. He did an okay job, but got a couple of the outriggers on crooked and actually never finished. Honestly, he was the one who noticed it first, but then he was very hard to pin down and get him back to finish, he was a friend of a friend, so I guess he felt he was doing me a favor even though I payed him in advance. For which I knew better! I will probably never get to old to do stupid sh#t. I even bought a used mig welder because he did not own one. One might say the handwriting was on the wall.

When I did finally get him back over I made the mistake of questioning something and he went ballistic and left without correcting the problem or finishing the job.

But all's well that ends well.
It was either at that point or just before that I enrolled in an adult education night time welding class. It was mostly arc (stick) welding using these ancient machines, but I took classes one night a week through the fall, winter and spring, running tons of beads and got my confidence up. As I mentioned I had also purchased a used Millermatic 140 Auto Set 120v mig welder for the other knucklehead to use fixing my frame so I was practicing with it as well. Bottom line I got good enough to fix the outriggers he messed up and added about 10 more including recycling a few I'd cut off and replaced initially. With those I just cut off the worst parts and welded them to another outrigger where I wanted additional support for flooring or floor channel.

As my confidence and skill increased I got braver and added support in the front of the frame where they was a huge span where the spare tire rides inside the frame. That span was something like 57" at the widest point side to side and 36 inches front to back. Here's a link to what I did there. I had to do it this way because it's a tight fit with the tire in place. https://photos.app.goo.gl/Vj43KhKjehHaGzfm6

I also replaced my step outriggers and made my own gussets because the new ones from www.odmrv.com don't come with them and they don't seem to be available. I made them from 14g sheet metal, cutting them out on my Shopsmith bandsaw.
https://photos.app.goo.gl/EAc9nmBCZLiKRiMU9

BTW, odmrv.com is a great source for reasonably priced outriggers as well as many more Airstream parts. I also replaced the bottom to my front battery / storage box. And added a steel shelf in my rear bumper wet box.
https://photos.app.goo.gl/5Kwugx4u6EppzWTY7

The way mine was when I bought it in 2012 the bottom of the rear bumper box was just the thin badly rotted belly pan aluminum.
Now it's a 14g steel bottom. It'll require a bit more maintenance, but it should be much better.
https://photos.app.goo.gl/v3cqF7M6azMwvDET8

I'm going to coat the inside of the bumper box and front storage box with bed liner. This GD trailer should be good for another 50 years.

So, I got my rear floor templates finished today.
https://photos.app.goo.gl/tm6nn3nruWbR5iR59

Possibly I'll be able to start putting the Coosa board down tomorrow which is why I started this thread last year.Ha! Well, later today actually, hahaha. Damn it's late. Signing off.[emoji28]

[Re-Pete]

Originally Posted by skyguyscott

RePete,

Apologies for the tardy response; busy week.

Here is a link to one of many on the forum regarding a fix to water intrusion at the rear bumper (with helpful pics):

http://www.airforums.com/forums/f456...te-184009.html

Give a shout of thanks to the OP. This one is fairly simple and involves installing some flashing under the rub rail.

Others have just tried to caulk or silkaflex around the joint, but with all the vibration, I think the flashing method would be more effective in the long run.

I also owe something of an apology to AS; earlier I stated that AS had not bothered to address this flaw for some 50 years. The flaw started with the new body style away from the whale tail in 1969. Evidently, according to the above post, AS did attempt a fix in 2012. Better late than never. I am not familiar with what AS did to fix the problem, nor how effective their fix was.

skyguyscott, Thank you for this link. I need all the help I can get. [emoji28]

[Re-Pete]

Originally Posted by skyguyscott

In my case, when I purchased my 1969 trailer in the early 2000s, both the front and rear floor were soft, along with the area inside the door.

Since I lived fairly close to JC, I spent a considerable sum to have the factory replace these sections of the floor. They used plywood.

Some 12 years later, the area of the floor by the door, under the fridge and around the right wheel well were also soft, evidently from undetected water intrusion in the part of the coach difficult to inspect.

Note that the added material cost of installing Coosa, in my case, in the first instance would have been cheaper than doing it twice with Plywood, not to mention the time and headache of it all.

For some, installing plywood may be the most cost effective choice, especially if they don't plan on keeping the trailer for a long time, or if they are confident they can keep abreast of any insidious water intrusion for the rest of their lives, including as they age and mobility starts to become an issue.

For me, spending a little extra in material costs to fix the problem once and for all is well worth it.

My feelings exactly. It's certainly not like I expect that once I'm finished this beauty will never leak again. On the contrary, I'm counting on the fact that out will leak and trying to build in checks for that. Such as drains in the floor channel so thst water, if it gets in (when) will have a path to exit without causing a bit of damage. Having a floor that won't rot out if also reassuring.

For the neigh sayers, I hear your message too, and I respect your right to rebuild your rig as you see fit. Please respect my right to do the same.

[Re-Pete]

Originally Posted by Allen Arin

Get the coosa or Penske board. It's super straight and holds screws great. I would glass over It with a layer of mat and maybe sand it somewhat smooth because that stuff is pretty rough. I'm not a upholster guy so I may be wrong about the last part.

Last thing WEAR GLOVES!

Greetings Allen,

I missed your post initially, but thankfully I was rereading some posts and saw it. I agree that the Coosa is a bit rough.

I have a couple questions. If you have time to answer them, that would be great.
I know next to nothing about fiber glassing. Here are my questions: What is mat and how difficult is what you are suggesting? What would be the benefit of "glass over It with a layer of mat and maybe sand it somewhat smooth because that stuff is pretty rough"?