Marine Ply, HDPE, Exterior Ply

[Rawlings]

Hi guys, we are getting ready to go out and purchase our materials for starting our Crown Bus conversion. I am looking to insulate the sidewalls and the floor and then cover everything with Either Marine Plywood, HDPE Panel, or Exterior ply. The issue I am having is obviously the costs. Based on our calculations to cover the side walls and the floor with Marine Plywood it would cost almost $700-800 for 3/4 thick Marine Ply. I have seen HDPE panels for a little less for 1/4 thickness (Now I know HDPE is stronger than Plywood so I am not sure if this mean its okay to go with less tickness) I would gain the no rotting risk and purely waterproof. Then there's Plywood with X rating such as ABX or ACX or CDX. What would be your recommendations if I want to save a little bit of money but still be well protected from possible water damage. Knowing how these buses can and will always have water leak issues from rain etc I obviously don't want to skimp out but I also don't want to break the bank. I am also thinking of using the HDPE and Marine as combination, perhaps the Marine as subfloor and the HDPE as the side walls that are behind the cabinets etc or vice versa

Marine Ply
https://www.menards.com/main/buildin...4452503795.htm

HDPE Panel
https://www.menards.com/main/buildin...4424093657.htm

BCX Ply
https://www.menards.com/main/buildin...4431327232.htm

[o1marc]

You are aware that the A,B,C,and D are grade qualities. A being the best. An ABX would best quality on one side and a B quality on the other AC has lesser quality on one side and CD is cheap fill plywood

[Rawlings]

Originally Posted by o1marc

You are aware that the A,B,C,and D are grade qualities. A being the best. An ABX would best quality on one side and a B quality on the other AC has lesser quality on one side and CD is cheap fill plywood

I am aware of the ratings, what I'm asking is if skimping on marine grade and going with ABX plywood would still be acceptable ...obviously I would paint it/seal it to make it much more "water resistant" and if anyone had experience using HDPE rather than Plywood.

[o1marc]

Originally Posted by Rawlings

I am aware of the ratings, what I'm asking is if skimping on marine grade and going with ABX plywood would still be acceptable ...obviously I would paint it/seal it to make it much more "water resistant" and if anyone had experience using HDPE rather than Plywood.

Marine ply is for wet applications. If you don't plan on having it wet inside then Marine would be cost not needed. If the plywood shows I would use AB, if it's hidden, CD, it's cheaper. Just not OSB.

[Rawlings]

Originally Posted by o1marc

Marine ply is for wet applications. If you don't plan on having it wet inside then Marine would be cost not needed. If the plywood shows I would use AB, if it's hidden, CD, it's cheaper. Just not OSB.

So ABX would do just fine for inside of bus for wall coverings...it'll be sealed with quality paint... Say it happens to rain and over time some rain gets inside ...or there's a leak from a pipe or something would it hold up as long as it's dealt with ... I have been reading marine might be over kill but since these buses are leaky tin cans ..no matter how much you work to weather proof them there will always be small little leak issues etc.

I guess I could go with ABX for walls and Marine for floor...there's already marine ply under the rubber covering..this was standard for crowns and most people recommend not to remove the rubber cause it's glued to the marine ply below..I checked the marine plywood under the bus and it is still in great condition and with most crowns being aluminum there's hardly rust issues ..so I plan to put some insulation over the rubber floor and then marine ply over that...then the vinyl flooring or wood flooring I decide to go with... Guessing floor gets more water to it then walls would you say?

[o1marc]

Originally Posted by Rawlings

So ABX would do just fine for inside of bus for wall coverings...it'll be sealed with quality paint... Say it happens to rain and over time some rain gets inside ...or there's a leak from a pipe or something would it hold up as long as it's dealt with ... I have been reading marine might be over kill but since these buses are leaky tin cans ..no matter how much you work to weather proof them there will always be small little leak issues etc.

I guess I could go with ABX for walls and Marine for floor...there's already marine ply under the rubber covering..this was standard for crowns and most people recommend not to remove the rubber cause it's glued to the marine ply below..I checked the marine plywood under the bus and it is still in great condition and with most crowns being aluminum there's hardly rust issues ..so I plan to put some insulation over the rubber floor and then marine ply over that...then the vinyl flooring or wood flooring I decide to go with... Guessing floor gets more water to it then walls would you say?

The floors always take the most abuse from rust. You could be making a serious mistake if you don't address it now. Not smart to build a house on a rotting foundation. You can't always tell how bad the floor is from underneath the bus.
Water on plywood doesn't do instant damage, it happens gradually over time.

[Rawlings]

Originally Posted by o1marc

The floors always take the most abuse from rust. You could be making a serious mistake if you don't address it now. Not smart to build a house on a rotting foundation. You can't always tell how bad the floor is from underneath the bus.
Water on plywood doesn't do instant damage, it happens gradually over time.

The floor isn't of metal like most buses. It's marine plywood that's coated and sealed. You can see it from underneath the bus it's held by the chasis etc as I mentioned most of the crown bus is aluminum it has very little rust as it was a California bus from Riverside/mostly desert it's in great condition i looked at the condition of the supports holding the marine plywood and they look to be in good shape. On the inside the marine plywood is covered by the plastic /vinyl black floor from the bus, I plan to put insulation over that and then another 3/4 of more marine plywood or ABX plywood which will make it even stronger should there be any issues with the plywood under it would still be supported by the beams and chasis. I totally understand the rust for other buses as I see they are all mostly metal floors that rust through but crowns don't have this type of surface. I'm mostly worried of any future leaks coming from big storms and water getting in as I will have cabinets, etc I'm thinking ABX walls and additional marine plywood subfloors.

[o1marc]

Originally Posted by Rawlings

The floor isn't of metal like most buses. It's marine plywood that's coated and sealed. You can see it from underneath the bus it's held by the chasis etc as I mentioned most of the crown bus is aluminum it has very little rust as it was a California bus from Riverside/mostly desert it's in great condition i looked at the condition of the supports holding the marine plywood and they look to be in good shape. On the inside the marine plywood is covered by the plastic /vinyl black floor from the bus, I plan to put insulation over that and then another 3/4 of more marine plywood or ABX plywood which will make it even stronger should there be any issues with the plywood under it would still be supported by the beams and chasis. I totally understand the rust for other buses as I see they are all mostly metal floors that rust through but crowns don't have this type of surface. I'm mostly worried of any future leaks coming from big storms and water getting in as I will have cabinets, etc I'm thinking ABX walls and additional marine plywood subfloors.

I stand corrected on your floor. You might consider, like many of us, putting your bus to a leak test while its gutted and find and fix any leaks. Fortunately Mother Nature has been the one holding the hose lately and making it quite obvious where my leaks are.

[Rawlings]

Originally Posted by o1marc

I stand corrected on your floor. You might consider, like many of us, putting your bus to a leak test while its gutted and find and fix any leaks. Fortunately Mother Nature has been the one holding the hose lately and making it quite obvious where my leaks are.

Yeah it hasn't rained as much when Im able to go into the bus and check..I've used a hose and high pressure to test several areas to see where water is coming in from...I've noticed water is coming in from the emergency door...around the top...I'm guessing the gasket is old and worn...wondering if these are universal gaskets that would fit any bus emergency door .. also some water is going through a couple Windows as they don't always shut all the way up... The bus has an ingenious gutter system and any water that flows down the windows and sides goes through Chambers that come down through the bus walls and out.... It's quite amazing. But some water is getting through some windows where they shut on top of it's raining or water being sprayed very hard in some of these little crevices ...if the bus is parked and it's raining down no water goes through the windows but if I'm driving at highway speeds or if I hose it directly at the window we see some getting through where the window shuts. Also some of the glass gaskets in windows are chipped so some is getting through there too I can't find gaskets so I'm guessing I'll have to find some very good caulking for exterior

Aside from that...not much more leaking...some is getting through the front and leaking down by the gas and break pedals but very little I'm guessing the front bus covers have a few places that the gasket holding these front of bus panels have some wear.

[o1marc]

Originally Posted by Rawlings

Yeah it hasn't rained as much when Im able to go into the bus and check..I've used a hose and high pressure to test several areas to see where water is coming in from...I've noticed water is coming in from the emergency door...around the top...I'm guessing the gasket is old and worn...wondering if these are universal gaskets that would fit any bus emergency door .. also some water is going through a couple Windows as they don't always shut all the way up... The bus has an ingenious gutter system and any water that flows down the windows and sides goes through Chambers that come down through the bus walls and out.... It's quite amazing. But some water is getting through some windows where they shut on top of it's raining or water being sprayed very hard in some of these little crevices ...if the bus is parked and it's raining down no water goes through the windows but if I'm driving at highway speeds or if I hose it directly at the window we see some getting through where the window shuts. Also some of the glass gaskets in windows are chipped so some is getting through there too I can't find gaskets so I'm guessing I'll have to find some very good caulking for exterior

Aside from that...not much more leaking...some is getting through the front and leaking down by the gas and break pedals but very little I'm guessing the front bus covers have a few places that the gasket holding these front of bus panels have some wear.

Ya, I hear ya, I'm still contemplating deleting all the bus side windows except the 6 in the rear garage, and replacing with RV windows. My windows have a double sided tape seal around the bottom and sides, but not at the top. Many of mine don't close properly either, poor design, common failure.

[Rawlings]

Originally Posted by o1marc

I stand corrected on your floor. You might consider, like many of us, putting your bus to a leak test while its gutted and find and fix any leaks. Fortunately Mother Nature has been the one holding the hose lately and making it quite obvious where my leaks are.

I hope I can get my wife to agree to delete some of the windows she wants a very open concept and a lot of light coming into the bus to make it look bigger and not cramped however we would be giving up a lot to heat since having all those windows would bring in a lot of heat from sun when we camo etc. ...I do like the look of having less shelving and be able to see all windows and look out...we will add curtains but ...I'm weary of all these windows and having small water issues ...guess I can caulk and make some windows permanently shut... Lol

[Rawlings]

Okay so we bought ACX Plywood 4x8 sheets. We purchased 12 3/4'' 4x8 sheets for $469 of which I will get $50 in mail in rebate. That should cover all of our walls, build some of our cabinets and bed. Hell I was looking at Marine for the walls and subfloor (on top of marine sub floor that is already there) but the price for just 6 sheets was 500 bucks. We decided on the ACX because we plan on waterproofing as much as possible and we will seal the ACX ply extensively. I think this will help protect it.

We are still thinking of putting Marine 1/4 on the ceiling. It seems to be flexible enough to form it into the round ceiling shape.

Any recommendation on what to use to seal these ACX boards? Does a type of paint work or does it have to be epoxy? I am guessing they have epoxy paints?

[Sleddgracer]

Originally Posted by Rawlings

Okay so we bought ACX Plywood 4x8 sheets. We purchased 12 3/4'' 4x8 sheets for $469 of which I will get $50 in mail in rebate. That should cover all of our walls, build some of our cabinets and bed. Hell I was looking at Marine for the walls and subfloor (on top of marine sub floor that is already there) but the price for just 6 sheets was 500 bucks. We decided on the ACX because we plan on waterproofing as much as possible and we will seal the ACX ply extensively. I think this will help protect it.

We are still thinking of putting Marine 1/4 on the ceiling. It seems to be flexible enough to form it into the round ceiling shape.

Any recommendation on what to use to seal these ACX boards? Does a type of paint work or does it have to be epoxy? I am guessing they have epoxy paints?

first, sand the bare wood to rough up the planer glaze - for a clear coat finish you can seal that by diluting your finish product by 10% , then 2 finish coats ( be sure to sand between each coat ) - for painting, seal with a primer/sealer, then finish with 2 coats of your chosen finish - be sure to sand between coats - it makes a huge difference in the finished product

[Rawlings]

Originally Posted by Sleddgracer

first, sand the bare wood to rough up the planer glaze - for a clear coat finish you can seal that by diluting your finish product by 10% , then 2 finish coats ( be sure to sand between each coat ) - for painting, seal with a primer/sealer, then finish with 2 coats of your chosen finish - be sure to sand between coats - it makes a huge difference in the finished product

What primer and paint would you recommend?

[Sleddgracer]

Originally Posted by Rawlings

What primer and paint would you recommend?

any of the name brands should be fine - in my area ( BC Canada ) I would likely go with General Paints, or Benjamin Moore products - the dealers in those stores generally have clerks that know their products and can answer any questions and give advice

[Dirtdoctor]

No OSB, regular ply- seal the stuff and run with it. If you can toss some insulation on the flooring toCut the road noise and heat.
Cheers


Oh redguard shower sealant is flexible and works well. Also there is a rubberized roof sealant that is great too.

[Sharee100]

I have a smaller shuttle bus (Chevy Express 3500 6.5 L turbo diesel). I removed down to the bottom layer of plywood. Then I covered that with more plywood ABX 3/4 inch, then 2 x 4 studs turned sideways and filled with 1 1/2 inch solid insulation, and another layer of 3/4 inch abx plywood, and last my vinyl sheet flooring. I plan to spray insulate underside of bus plywood layer to seal out moisture. I am going to get advice from a professional on how to insulate the walls (Jeff Flake at Vanlife Conversions in NC) before I do the walls. i plan to replace my windows, and seal as much as possible. I know all sized buses tend to leak, especially if not maintained by prior owners.

[Drew Bru]

Originally Posted by Rawlings

Any recommendation on what to use to seal these ACX boards? Does a type of paint work or does it have to be epoxy? I am guessing they have epoxy paints?

I've not tried it, but I've seen that people use Drylok on plywood for use in water tanks and sorta amphibian type enclosures (lizards, turtles and whatnot). Apparently it's a poor-man's marine plywood.

[pengyou]

Almost every bus and home project I have seen is made with 3/4" plywood. How much difference is there between 3/4", 1/2", 3/8", 5/8" and 1/4" in strength? I was thinking if you are just covering walls, 1/4" or 3/8" would be fine.

[Sharee100]

I have seen that others are using the thinner plywood on the walls with insulation. Think about it...You don't walk on the walls.