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soldiermedic · 03-15-2007, 10:09 AM

I know that there have been many threads on this but I did not find one unique to my question. I had a new frame fabricated for my 68 Safari, and with it goes a new floor. The current plan is for 1/2" Marine grade plywood. I keep reading that most people have 5/8. Will this 1/8 thinner piece of plywood have a detrimental effect on the coach's floor? There is going to be some kind of flooring laid on top of it after installation, but I have the chance now to change the floor (It will cost me about $400), but should it be done?

Steve

Wabbiteer · 03-15-2007, 10:28 AM

What spacing did the frame cross-members get installed at? 24" is a long gap to bridge with 5/8" or 1/2" plywood. I would be tempted to go oversize another step to 3/4 even if the edges then require removing thickness to clip into shell framing. I have a rear bath section that will be coming out this spring (5 days until spring, I'm in trouble) and will be shopping plywood pretty hard too...

Aerowood · 03-15-2007, 10:33 AM

My 71 Globetrotter had 5/8 and I upped to 3/4. New floor is much firmer then the old. No regrets

markdoane · 03-15-2007, 10:50 AM

My '59 Tradewind was 5/8". I upgraded to 3/4", then added a moisture barrier and 1/4" pine underlayment. Next I will add 7/16" cork.

I'm glad I upgraded the axle.

LI Pets · 03-15-2007, 01:24 PM

I used 1/2".

But understand something about marine plywood.

Your wasting your money!

The only difference between marine and exterior grade is that the inner plys of marine have no knots from voids.

The glue is the same.

In a boat it matters.

In our use it is not required, buy exterior.

Jim & Susan · 03-15-2007, 01:44 PM

I used 3/4" exterior grade. That's what mine came with from the factory. I considered marine grade, but it was 2 to 3 time the cost. Which ever one I decided to use, I was going to treat it with epoxy and Varathane, regardless, so I opted for the cheaper plywood.

Jim

FreshAir · 03-15-2007, 01:46 PM

I am now completing my installation of the rear bath floor in my '66 Trade Wind. I decided to stay with the 5/8 thickness as the new would be butting up to the old. The 5/8 seems adequate in my AS. The remainder of the flooring is pretty solid.
Neil.

bobkelly · 03-15-2007, 04:22 PM

Congratulations on the new frame for the restoration. The thickness of the plywood is very significant to both the performance and feel of the floor. If your new frame was designed specifically to support 1/2" plywood, great. The supports for the plywood will be closer together than for a thicker floor.

If not, a 5/8" floor is 25% thicker than a 1/2" and will deflect much less when walked on.

soldiermedic · 03-15-2007, 05:53 PM

Quote:

Originally Posted by Wabbiteer

What spacing did the frame cross-members get installed at? 24" is a long gap to bridge with 5/8" or 1/2" plywood. I would be tempted to go oversize another step to 3/4 even if the edges then require removing thickness to clip into shell framing. I have a rear bath section that will be coming out this spring (5 days until spring, I'm in trouble) and will be shopping plywood pretty hard too...

Wabs, the spacing is identical to the original frame. I had them recreate the frame to the same specifications so that everything word work out well. I originally got the 1/2 inch because that is what I assumed it was after looking at it. Stupid me to not measure until I had already gotten the supplies. If Bob has used 1/2 inch and it turned out ok then I should be ok. It will have another layer over it anyhow so I am not to worried about it.

Steve

LI Pets · 03-15-2007, 06:27 PM

You said another layer, of what?

soldiermedic · 03-15-2007, 08:01 PM

Some kind oflaminate or hardwood flooring. If I need I can add a layer of luan over the subfloor.

uwe · 03-15-2007, 08:12 PM

Ah, I don't think 1/2 in is a good idea. It will deflect a lot when you walk on it, and it will detract from teh original strength of design. 5/8 was original for your trailer.
Even if you put a solid material on top, it will still deflect quite a bit. Makes the trailer feel spongy.
I used 5/8 and wish I had gone to 3/4 for my Overlander. It has a cork flooring on top, and it still deflects a bit.

LI Pets · 03-15-2007, 08:37 PM

My method, use the 1/2", don't use layer of any type of heavy wood that can absorb moisture.

Just get 6 oz fiberglass cloth on top of the wood with epoxy resin,
then (well wait till it dries) jump up and down tell us how much it flexes.

I'll make you a bet it won't be much at all well within specs.

If you add a pergo type floor over that then try it with an 800 lb gorrilla

You will save a lot of weight and have a bullet proof floor.

You can buy the fiberglass and MAS epoxy at Jamestown boat supply in RI, at good prices.

soldiermedic · 03-16-2007, 07:56 AM

Quote:

Originally Posted by LI Pets

My method, use the 1/2", don't use layer of any type of heavy wood that can absorb moisture.

Just get 6 oz fiberglass cloth on top of the wood with epoxy resin,
then (well wait till it dries) jump up and down tell us how much it flexes.

I'll make you a bet it won't be much at all well within specs.

If you add a pergo type floor over that then try it with an 800 lb gorrilla

You will save a lot of weight and have a bullet proof floor.

You can buy the fiberglass and MAS epoxy at Jamestown boat supply in RI, at good prices.

Did the fiberglass and resin add more weight then the extra 1/8th inch of wood from the 5/8th?

ZoominC6 · 03-16-2007, 10:53 AM

If it's all about the money, go with plywood, marine grade or exterior grade. If it's about durability and the lifetime of the floor, consider this; visit your local lumberyard and inquire about ADVANTEC. I believe that I have the spelling correct, anyhow, they will know what to tell you. This 'plywood' comes with a guarantee that you will need to ask about. I've used it in construction and tested it in all kinds of weather over a yearlong project. It never changes in thickness or character. We utilized it from that point forward in subfloors that would be exposed to the elements for long periods until the roof was 'dried in'. The material is a little heavier than plywood and is costly; however, darned good insurance for the long haul. Good luck.
HAPPY TRAILS

markdoane · 03-16-2007, 11:17 AM

Quote:

Originally Posted by ZoominC6

. . consider this; visit your local lumberyard and inquire about ADVANTEC. I believe that I have the spelling correct, anyhow, they will know what to tell you.

The spelling is Advantech, manufactured by Huber.
I used exterior plywood on my floor, but if i was doing it again I would use Advantech. The specs are just to good to ignore.

ZoominC6 · 03-16-2007, 11:27 AM

Thanks for 'spellchecking' me Mark! ;-) and for confirming my thoughts about the product. Modern technology is great, even if we do pay more for it at times.

LI Pets · 03-16-2007, 05:22 PM

maybe 10-12lbs, the benefits out weight that many times over.

Hillgenberg · 03-16-2007, 08:35 PM

I like your idea of using fiberglass cloth and the resin. I have a small area I need to repair and had no idea how to handle the situation til I read your article.

Ken J · 03-17-2007, 10:03 AM

The Airstream floor is 5/8 - however the tile on top of the floor (in which the shell sets on) is 1/8 - so 5/8 + 1/8 = 6/8 or 3/4. This is a calculation I missed when I did my floor - I saw the plywood was 5/8 so that is what I used - I wished I had used the 3/4 - oh well - the 5/8 is working well, the tile on top probably does not add any structure anyway and is just filler.

Ken J.