Marine Grade Plywood or Coosa Board That is the Question

[Adinafloyd]

I am also curious about which fasteners were used on the coosa...

[Re-Pete]

Originally Posted by jcarp

I am full skin off putting coosa as sub floor. What fasteners did you use and how did you seal the seams

Originally Posted by Adinafloyd

I am also curious about which fasteners were used on the coosa...

This is what I ended up ordering from albanycountyfasteners.com.

The ones I purchased were 1-1/2” long. Click the link above to go to them. These are very similar to the screws that AS used when they built our Excella. The only difference is that the original screws were wafer head screws which have a bit of a rim around the top of the head. That said a PO had done a repair to the floor in the bedroom and they used this type of screw so I’m assuming they had the same problem finding thread cutting wafer head screws. These are made for screwing flooring down to heavy gauge sheet metal and should work fine. The originals screws were also thread cutting and they held great, even the ones that were rusted from water damage. These have the torx star drive which I also like. We’ve just re-flipped our frame right side up and are preparing to install our Coosa flooring.


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Star Drive 6 Lobe Flat Head Thread Cutting Screws | Black Phosphate + Oil Finish - Type F

Diameter - Thread Pitch: 1/4"-20

[Re-Pete]

Originally Posted by Isuzusweet

I half lapped my joints....using a router with a 3/4" wing cutter I set up the router to just barely cut over half the thickness of the Coosa. So add 3/8" over center of support beam to a sheet when you cut it. When you fasten the sheet , the fasterner will be in the center of the support.

This process enabled me to A) Have flush joints all the way across regardless of what the gridwork was doing below the Coosa, as the half lap below supported the half lap above; B) By cutting just a hair over, it allowed me to silicone the joint together. C) It also meant that I was fastening down two sheets using only one line of fasteners.

Hope this helps.
Sidekick Tony

Hello again Sidekick Tony, I hope all is well and that you are still in the information sharing business.

We are very nearly ready to begin installing our 3/4" Coosa Bluewater 26 flooring. The most efficient layout is to run the boards lengthwise along the legth of the AS frame. This will require a center seam right down the middle and a few crosswise seams. (flooring is roughly 25+Ft.) So, your use of rabbet or lap joints seems to be the ticket.

I'm not proficient with a router. What type would you recommend using for this and did you use anything besides the Coosa edge to ride the bearing along?
Also, I need to reduce the Coosa to fit into the outside aluminum channel which is a tight 1/2". In order to keep the Coosa and channel flush at the bottom where they lay on the, outriggers I need to remove the excess thickness about 1/4" deep all from the top side along the edge approximately 1-5/8" wide to clear the top part of the channel. This is just for the channel, not the joint laps which I intend to do 3/4" widths as you described. Even though I don't really know this for a fact, a 1-5/8" rabbet seems a bit too wide to do with a router. I do not have a router table. I'm kind of thinking I may need to use a dado set for the channel edge just because of the span, running it over the dado set and moving the saw fence between passes to achieve the correct width. Even this width won't be easy as I'll be doing it along the 8' length of each board and with a Shopsmith to boot. It's gonna be tight in the area I have to work in. Any experience or thoughts on this?

I'll take all the advice I can get. This stuffs to expensive for re-dos.

[jcarp]

Cant find coosa blue 26 3/4 inch in stock on west coast. Any help out there! I am ready to buy ....live in Portland, Oregon

[Re-Pete]

Originally Posted by jcarp

Cant find coosa blue 26 3/4 inch in stock on west coast. Any help out there! I am ready to buy ....live in Portland, Oregon

Call Coosa Composites, LLC and ask for a list of their nearest and most active distributors in your area. Here's a link.

Good luck.

[toastie]

Marine or Coosa a complete waste of money, you're not building a boat, would recommend 3/4" AC plywood, plus it cheaper.

toastie

[Isuzusweet]

Originally Posted by toastie

Marine or Coosa a complete waste of money, you're not building a boat, would recommend 3/4" AC plywood, plus it cheaper.

toastie

If you think Marine or Coosa is a waste of money....go to another thread where your opinion means something.

[skyguyscott]

He's a nice guy, Toastie -- aren't all Canadians?

But some of us think Coosa is a great bargain once you factor in the cost of Labor, time, etc. of patching or replacing the plywood floor. I had to patch several sections of floor in my 1969 TWICE in 15 years, done at the factory, and that cost more than doing it once with Cossa would cost.

To me, a waste of money is buying a brand new AS when you could buy a vintage one, fix it up (including replacing the floor with waterproof, lightweight Coosa) and end up with a better, nicer, awesome trailer for a fraction of new!

But, fortunately, what constitutes a waste of money is in the balance sheet of the purchaser, and keeps the good folks at JC employed in a respectable job.

[toastie]

Originally Posted by Isuzusweet

If you think Marine or Coosa is a waste of money....go to another thread where your opinion means something.

Isuzusweet

Apparently my opinions mean something, my thread has over 316,587 views, more views then anybody on the forum.

http://www.airforums.com/forums/f36/...ent-38289.html

toastie

[skyguyscott]

Originally Posted by toastie

... my thread has over 316,587 views, more views then anybody on the forum...

Yes, exactly. A highly read thread about floor replacement underscores how bad and how common a problem it is in Airstreams... hence the desire to fix it once and for all with something like Coosa, eh?

[Isuzusweet]

Originally Posted by Re-Pete

I'm not proficient with a router. What type would you recommend using for this and did you use anything besides the Coosa edge to ride the bearing along?
Also, I need to reduce the Coosa to fit into the outside aluminum channel which is a tight 1/2". In order to keep the Coosa and channel flush at the bottom where they lay on the, outriggers I need to remove the excess thickness about 1/4" deep all from the top side along the edge approximately 1-5/8" wide to clear the top part of the channel. This is just for the channel, not the joint laps which I intend to do 3/4" widths as you described. Even though I don't really know this for a fact, a 1-5/8" rabbet seems a bit too wide to do with a router. I do not have a router table. I'm kind of thinking I may need to use a dado set for the channel edge just because of the span, running it over the dado set and moving the saw fence between passes to achieve the correct width. Even this width won't be easy as I'll be doing it along the 8' length of each board and with a Shopsmith to boot. It's gonna be tight in the area I have to work in. Any experience or thoughts on this?

I'll take all the advice I can get. This stuffs to expensive for re-dos.

Any 1 1/2 horse router will do. I would at first straight router a straight edge on the sheet, with a nice straight piece of MDF, or something like that, and a top or bottom mounted bearing bit to straighten the edge of the board out before running through a table saw, (if you have a 10' sliding table saw, you could easily straighten out the edge).

Once cut, Coosa will support a bearing easily.

You can easily use a dado to remove the excess from the outside. What I'd be inclined to do is to dado from the inside cut, to the outside leaving a 1/4" or so of Coosa remaining on the outside of the sheet. This will support the Coosa on the inside and outside as you run across the blades, giving you an even cut. Basically you're cutting a 1/4" x 1/3/8" trench. The remaining 1/4" can easily be knocked off and sanded into a round, to allow easily fitting.

TIP! Take a couple of straight pieces of something 4' long, anything; make a couple of stands so that the edge of the vertical boards are the same height as your saw bed, infeed and outfield. Place vertical boards so that they close to the middle of the Coosa board you're cutting to support the board. You can add a wider strip on top of the boards to give you more stability, but the Coosa is very light.

Cheers
Sidekick Tony

[Isuzusweet]

Originally Posted by toastie

Isuzusweet

Apparently my opinions mean something, my thread has over 316,587 views, more views then anybody on the forum.

http://www.airforums.com/forums/f36/...ent-38289.html

toastie

I wouldn't be bragging if 316,587 people told me I was wrong.

You're a legend in your own mind.

[Re-Pete]

Originally Posted by Isuzusweet

Any 1 1/2 horse router will do. I would at first straight router a straight edge on the sheet, with a nice straight piece of MDF, or something like that, and a top or bottom mounted bearing bit to straighten the edge of the board out before running through a table saw, (if you have a 10' sliding table saw, you could easily straighten out the edge).

Once cut, Coosa will support a bearing easily.

You can easily use a dado to remove the excess from the outside. What I'd be inclined to do is to dado from the inside cut, to the outside leaving a 1/4" or so of Coosa remaining on the outside of the sheet. This will support the Coosa on the inside and outside as you run across the blades, giving you an even cut. Basically you're cutting a 1/4" x 1/3/8" trench. The remaining 1/4" can easily be knocked off and sanded into a round, to allow easily fitting.

TIP! Take a couple of straight pieces of something 4' long, anything; make a couple of stands so that the edge of the vertical boards are the same height as your saw bed, infeed and outfield. Place vertical boards so that they close to the middle of the Coosa board you're cutting to support the board. You can add a wider strip on top of the boards to give you more stability, but the Coosa is very light.

Cheers
Sidekick Tony

Tony,
Thanks again for you sharing your knowledge and suggestions regarding aligning the Coosa, best way to dado, router size, etc. The edges on my Coosa boards look very straight and square, but having read your suggestion, I'll make sure before I do anything else. This is one of those important details where my lack of experience could certainly get me into trouble. No, I don't have a 10' sliding table saw. I'll be doing the cutting with a combination of Kreg track saw guides and a clamp on straightedge set up, a jigsaw, and a Shopsmith. I do have extension tables for Shopsmith which will hopefully help me get the what I need to do, done with the full/larger sheets. If not, I'll be finding someone with a bigger table saw.

Regarding your "Tip", I'm trying to picture what you are describing. Are you referring to setting up extended in-feed and out-feed tables? If that's the case then I understand.

[Isuzusweet]

[QUOTE=Re-Pete;225763)

Regarding your "Tip", I'm trying to picture what you are describing. Are you referring to setting up extended in-feed and out-feed tables? If that's the case then I understand.[/QUOTE]

Yes

[Re-Pete]

Originally Posted by Isuzusweet

Yes

[emoji106], Thanks

[Allen Arin]

Originally Posted by Re-Pete

Thanks for the info. Two reasons I'm considering Coosa. It's waterproof essentially and it's much lighter than plywood.

My frame had some significant rust issues, but the bad outriggers have been replaced and the rear part of the SS tube has been replaced. I have a friend who welds.

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!

[Shermy1987]

Originally Posted by Isuzusweet

If you think Marine or Coosa is a waste of money....go to another thread where your opinion means something.

Geez. The Coosa fanatics strike again.

If you're not competent enought to keep your trailer sealed up and water tight, then I guess Coosa is the right choice. Personally I'd rather do a bi annual inspection and keep water out of my trailer. Rot problem solved.

[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.

[Isuzusweet]

Originally Posted by Shermy1987

Geez. The Coosa fanatics strike again.

If you're not competent enought to keep your trailer sealed up and water tight, then I guess Coosa is the right choice. Personally I'd rather do a bi annual inspection and keep water out of my trailer. Rot problem solved.

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

[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.