Flooring material

s-m-h

New member
Sep 13, 2019
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I was pricing out marine grade ply for my floors and although there was some initial sticker shock, I decided to go ahead call my contractor buddy to
see if he could get a better price for me. He asked what was so special about the marine grade ply and I explained as best as i could. He suggested a
product called Medium-density overlay (MDO) would do the same thing for half the price.

After googling, it appears it is quite popular in the boating community.

Any experience or input about this product? I was quite surprised to find it has not been discussed here much at all...

TIA

Shawn
--
Shawn Harris
North Vancouver,
Canada
1977 Palm Beach 403
 
From what i can tell if you use MDO it needs to be painted. pay extra attention to the edges.
--
1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
 
I wouldn't use any particle board products, of any density, made of any
chipped up wood products for anything construction related. Heck, that
stuff will not even make good firewood. It usually treated with flame
retardant chemicals. Just look at the cabinets in most of the early GMC
built coaches. Shoot, that stuff won't even hold a screw.
I for sure would not use it in the floor of a coach.
The future owner of your coach will thank you.
Ben Franklin had it right. "Penny wise and Pound foolish" seems to fit
here. Minimum grade I would consider using in the floor would be multi
laminated EXTERIOR GRADE A-A, which describes the two good sides stuff.
Marine grade is my preference but I concur, it is pricey stuff.
I had a friend who worked for a Carnival Ride manufacturer who built
the Ride known as "Crazy Cars". It is a mobile unit, frequently erected and
taken down and moved to the next Carnival event. They started out using the
decking you described. Those rides were coming back to the manufacturer
faster than they left. Most of them required total replacement of the
decking.
So, they searched the world for a suitable upgrade. Settled upon a
multi-ply product made in Denmark or Sweden. It was like nothing I ever saw
made in the USA. It was totally saturated with some kind of epoxy like
resins and bonded in ovens. Heavy stuff. One 4 x 8 sheet of the stuff was
all a healthy adult man wanted to lift. No matter where you cut the stuff,
it looked like the outside edges on the kerf. I used to have some scraps of
that stuff around that he gave me. It cost 4 times as much as our best
plywood. But, they had 0 comebacks. Worth every penny. Goodwill is hard to
put a price on.
Jim Hupy
Salem, Oregon

On Fri, May 1, 2020, 7:34 AM Mike Hamm via Gmclist
wrote:

> From what i can tell if you use MDO it needs to be painted. pay extra
> attention to the edges.
> --
> 1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Thank guys.

Jim, It is not particle board. I am with you in that I would never use the stuff. I absolutely hate it. This is plywood impregnated with resins. As I
said, it is what is used for sign boards and concrete forming.

MDO not MDF. Very different stuff.
--
Shawn Harris
North Vancouver,
Canada
1977 Palm Beach 403
 
If you can buy 3/4” form board for less than marine grade that is a no
brainer. Install and you are done.

Sully
Bellevue wa

On Fri, May 1, 2020 at 9:03 AM Shawn Harris via Gmclist <

> Thank guys.
>
> Jim, It is not particle board. I am with you in that I would never use the
> stuff. I absolutely hate it. This is plywood impregnated with resins. As I
> said, it is what is used for sign boards and concrete forming.
>
> MDO not MDF. Very different stuff.
> --
> Shawn Harris
> North Vancouver,
> Canada
> 1977 Palm Beach 403
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
From the website;

"17.5 mm Crown 43 is a Douglas fir panel that meets or exceeds CSA O121 for MDO Concrete Form. The high resin content MDO is applied in a one-step
process. All adhesives are fully waterproof phenolic resins that meet CSA exterior glue bond standards."

$57/sheet as opposed to $140/sheet for marine ply.
--
Shawn Harris
North Vancouver,
Canada
1977 Palm Beach 403
 
Shawn,

I've used quite a bit of MDO in construction and it would be fine for the floor in a GMC. As noted, all edges should be sealed particularly where
they're exposed at the wheel wells. You don't want to be doing this again in 40 years, do you? :)

MDO (Medium Density Overlay) is good quality plywood made with exterior glue and has a paper/resin surface applied on one or both sides. It is a
totally different animal than MDF (Medium Density Fiberboard), which is made from wood fibers and binding resin and is closer to Masonite. The two
are frequently confused because of the similarity between the acronyms. MDO would be fine for your coach's floor and MDF would not.

Git-Rot a very low viscosity epoxy that would soak into the exposed wood edges, probably only necessary at the wheel wells, and should be applied with
the edge to be sealed facing up. The stuff would run all over if you tried to apply it after the floor was laid down.

Richard
--
'77 Birchaven TZE...777;
'76 Palm Beach with 18,477 verified miles;
‘76 Edgemonte
 
Thanks Richard. I'll be sure to seal the edges. I'll see if i can find that Git-Rot "up here".
--
Shawn Harris
North Vancouver,
Canada
1977 Palm Beach 403
 
That resin impregnated stuff is as durable as any construction material
except for stone. I would definitely be in favour of using it. The floor on
my Royale is 1 and 1/2" in thickness. If you use a product of equal
thickness, you should be fine.
If you don't know by what I post here, I absolutely hate doing things
over again, no matter if it is structural or mechanical or electrical in
nature. I was taught by journeymen whose mantra was "If it won't last 200
years, don't waste your time doing it." Just me. Your experience is
different, not wrong, just different.
Jim Hupy
Salem, Oregon
Jim

On Fri, May 1, 2020, 9:07 AM Todd Sullivan via Gmclist <

> If you can buy 3/4” form board for less than marine grade that is a no
> brainer. Install and you are done.
>
> Sully
> Bellevue wa
>
> On Fri, May 1, 2020 at 9:03 AM Shawn Harris via Gmclist <

>
> > Thank guys.
> >
> > Jim, It is not particle board. I am with you in that I would never use
> the
> > stuff. I absolutely hate it. This is plywood impregnated with resins. As
> I
> > said, it is what is used for sign boards and concrete forming.
> >
> > MDO not MDF. Very different stuff.
> > --
> > Shawn Harris
> > North Vancouver,
> > Canada
> > 1977 Palm Beach 403
> >
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Back in the early 90's OSB (Oriented Strand Board) was just beginning to be used in the Las Vegas area construction arena. Being one of the 'old
school' types we inspectors didn't have a warm fuzzy about this upstart product. That feeling changed when we had some of that,unusual for Vegas,
moisture (rain) attack the uncovered roofs under construction. The OSB survived unscathed while many of the typical plywood 1/2" CDX panels needed to
be replaced. It was a real eye opener for sure. Some of the modern materials are better than the old stuff for sure.
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1975 Eleganza II, 101230,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM
 
> Back in the early 90's OSB (Oriented Strand Board) was just beginning to be used in the Las Vegas area construction arena. Being one of the 'old
> school' types we inspectors didn't have a warm fuzzy about this upstart product. That feeling changed when we had some of that,unusual for Vegas,
> moisture (rain) attack the uncovered roofs under construction. The OSB survived unscathed while many of the typical plywood 1/2" CDX panels needed
> to be replaced. It was a real eye opener for sure. Some of the modern materials are better than the old stuff for sure.
> Hal

Hal,

If that CDX had to be replaced after a Las Vegas rain, it was not real CDX. Counterfeit construction materials happen all the time. The only time I
was exposed to such a problem, the company sued the supplier who promptly replaced all the material that we could identify (my job), and then wrote
that the supplier admitted they made a mistake in processing.

Yes, don't buy marine plywood unless you need it. I used to buy a lot of it for jobs customers were paying for and so the price was not a big issue
to me.

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
My father in law was a highly decorated Marine. He served in WW 2, and in
Korea, surviving the Chosin Resevoir freeze out and human wave assaults
from the Chinese. This is just to let you guys know that he was an
honorable man, and one of my heroes.
When he returned stateside, he carefully packed away his uniforms, put
on a nail apron, traded in his M-1 rifle for a 16 oz hammer and went to
work for his father in law building custom homes. Learned his trade well,
took over the business, got his contractors license, and built custom homes
one at a time for happy owners for 60 years. He passed away at almost 101
years of age, and we buried him in that Marine uniform with full military
honours.
He did it all himself and he hired help when he needed it. He used
only the highest quality products in his houses, they were all stick framed
with full dimension materials, framed his rafters, built his own stair
risers, only used plywood sheathing of the highest and best quality. Made
his own kitchen cabinets, well you must get the picture by now. No particle
board or manufactured trusses in his houses. No pneumatic nail guns either.
Old School all the way. All of his contracts were verbal, sealed with
a firm handshake and a promise from his lips and a look from those steely
blue eyes.
He absolutely hated particle board, and manufactured (engineered)
trusses held together with nail plates. No short cut methods, either. His
subs were all lifelong friends and hunting and fishing buddies. He lived a
good life, raised 2 girls, never cheated on his wife, seldom swore, loved a
good joke and Chevas Regal 18 years old. Chukkar hunting every fall with
his constant companion German shorthair dog. Of which he had 5 in
succession.
He never lost his shooting eye, and was a national champion skeet
shooter well into his 60's. He had a whole shoebox full of awards and
medals that he won. We gave them to his grandkids after his passing.
Anyway, if George had his reasons for disliking a person or product,
you can be sure that there was a good reason for it.
Just my cockeyed take on it. Your opinions will vary.
Jim Hupy
Salem, Oregon

On Sat, May 2, 2020, 7:28 AM Matt Colie via Gmclist
wrote:

> > Back in the early 90's OSB (Oriented Strand Board) was just beginning to
> be used in the Las Vegas area construction arena. Being one of the 'old
> > school' types we inspectors didn't have a warm fuzzy about this upstart
> product. That feeling changed when we had some of that,unusual for Vegas,
> > moisture (rain) attack the uncovered roofs under construction. The OSB
> survived unscathed while many of the typical plywood 1/2" CDX panels needed
> > to be replaced. It was a real eye opener for sure. Some of the modern
> materials are better than the old stuff for sure.
> > Hal
>
> Hal,
>
> If that CDX had to be replaced after a Las Vegas rain, it was not real
> CDX. Counterfeit construction materials happen all the time. The only
> time I
> was exposed to such a problem, the company sued the supplier who promptly
> replaced all the material that we could identify (my job), and then wrote
> that the supplier admitted they made a mistake in processing.
>
> Yes, don't buy marine plywood unless you need it. I used to buy a lot of
> it for jobs customers were paying for and so the price was not a big issue
> to me.
>
> Matt
>
>
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
When 'something better' comes along, it behooves us to ask, better how? Often the answer is 'better in that it's cheaper to make'. F'rinstance,
disc brakes are better in stopping power than drums. Plastic tank aluminum radiators are merely better in cost.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
Especially something on our coaches that we don't want to replace again. Marine grade plywood IS expensive. But how long did the last piece of marine grade last? 30yrs? 40yrs? Spend the money and get the real stuff. What will it cost in terms of time and coach out of service to replace it again?

It goes without saying that material available at the home warehouses has no place in our coaches.

>
> When 'something better' comes along, it behooves us to ask, better how? Often the answer is 'better in replacethat it's cheaper to make'. F'rinstance,
> disc brakes are better in stopping power than drums. Plastic tank aluminum radiators are merely better in cost.
>
> --johnny
> --
> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> I forgive them all, save those who hurt the dogs. They must answer to me in hell
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Interesting to see the communities mixed responses to this question.

I am a buy once, cry once kinda guy but I also don't like throwing my money away.

Personally, I am sold on the MDO and will be using it.

This old dog is gonna try and learn a new trick.

Time will tell.

--
Shawn Harris
North Vancouver,
Canada
1977 Palm Beach 403
 
> > Back in the early 90's OSB (Oriented Strand Board) was just beginning to be used in the Las Vegas area construction arena. Being one of the
> > 'old school' types we inspectors didn't have a warm fuzzy about this upstart product. That feeling changed when we had some of that,unusual for
> > Vegas, moisture (rain) attack the uncovered roofs under construction. The OSB survived unscathed while many of the typical plywood 1/2" CDX panels
> > needed to be replaced. It was a real eye opener for sure. Some of the modern materials are better than the old stuff for sure.
> > Hal
>
> Hal,
>
> If that CDX had to be replaced after a Las Vegas rain, it was not real CDX. Counterfeit construction materials happen all the time. The only
> time I was exposed to such a problem, the company sued the supplier who promptly replaced all the material that we could identify (my job), and then
> wrote that the supplier admitted they made a mistake in processing.
>
> Yes, don't buy marine plywood unless you need it. I used to buy a lot of it for jobs customers were paying for and so the price was not a big
> issue to me.
>
> Matt


CDX isn't marine grade and if it were counterfeit there were hundreds if not thousands built with it from lots of different suppliers. Not a chance.
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1975 Eleganza II, 101230,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM
 
> > > Back in the early 90's OSB (Oriented Strand Board) was just beginning to be used in the Las Vegas area construction arena. Being one of
> > > the 'old school' types we inspectors didn't have a warm fuzzy about this upstart product. That feeling changed when we had some of that,unusual
> > > for Vegas, moisture (rain) attack the uncovered roofs under construction. The OSB survived unscathed while many of the typical plywood 1/2" CDX
> > > panels needed to be replaced. It was a real eye opener for sure. Some of the modern materials are better than the old stuff for sure.
> > > Hal
> >
> > Hal,
> >
> > If that CDX had to be replaced after a Las Vegas rain, it was not real CDX. Counterfeit construction materials happen all the time. The only
> > time I was exposed to such a problem, the company sued the supplier who promptly replaced all the material that we could identify (my job), and
> > then wrote that the supplier admitted they made a mistake in processing.
> >
> > Yes, don't buy marine plywood unless you need it. I used to buy a lot of it for jobs customers were paying for and so the price was not a big
> > issue to me.
> >
> > Matt
>
> CDX isn't marine grade and if it were counterfeit there were hundreds if not thousands built with it from lots of different suppliers. Not a
> chance.
> Hal

By the material standards CDX (actually any ??X) is supposed to be at least a completely water proof bond. Marine grade is the same, but that means
that there are no voids in the core. There are also varieties of marine grade that are more layers. Then there is the aircraft grades. Lets not go
there, they are scary expensive.

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Mdo is Heavy , just get a 3/4 cross strand ply (no voids) about $65 us it doesn’t have to be marine ply

Sent from my iPad

>
> I was pricing out marine grade ply for my floors and although there was some initial sticker shock, I decided to go ahead call my contractor buddy to
> see if he could get a better price for me. He asked what was so special about the marine grade ply and I explained as best as i could. He suggested a
> product called Medium-density overlay (MDO) would do the same thing for half the price.
>
> After googling, it appears it is quite popular in the boating community.
>
> Any experience or input about this product? I was quite surprised to find it has not been discussed here much at all...
>
> TIA
>
> Shawn
> --
> Shawn Harris
> North Vancouver,
> Canada
> 1977 Palm Beach 403
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
> Mdo is Heavy , just get a 3/4 cross strand ply (no voids) about $65 us it doesn’t have to be marine ply.

Dan,

MDO isn't relatively heavy. Are you thinking of MDF?
http://theplywood.com/weight

In Shawn's intended application, replacement of the GMC plywood floor, it would be tough to come up with a better and more cost effective product to
use than MDO.

Get up in a front wheel well and look at the underside of the exposed plywood - it's going to have a lot of checking. The checking is not desirable
for a number of reasons, the least of which is cosmetic. MDO won't do that.

Richard

--
'77 Birchaven TZE...777;
'76 Palm Beach with 18,477 verified miles;
‘76 Edgemonte
 
IS expensive. But how long did the last piece of marine grade last? 30yrs? 40yrs? Spend the money and get the real stuff. What will it cost in terms
of time and coach out of service to replace it again?

It goes without saying that material available at the home warehouses has no place in our coaches.

For the record, the last piece lasted quite some time but it was not marine grade plywood. It was simply exterior grade. The MDO I will be using is an
upgrade from the factory flooring.

--
Shawn Harris
North Vancouver,
Canada
1977 Palm Beach 403