Best Mold Resistant Subfloor Material

[COArgosy78]

I just posted to another thread about this exact subfloor alternative wanting opinions. At this point in my research, I think using the aluminum honeycomb is much more expensive than plywood, but as noted above could be a fix it and forget it substitute. Here is my post:

Hi There -

I would like to get some thoughts on this subject, but with a different type material. We too are going to have to do some floor repair on the front plywood of our Minuet. We plan to only do the 1 panel at this point and I have been looking into this:

http://www.cptpanels.com/materials/core-materials/

The company is located in Canada, but I called their toll free # and talked to an engineer there. The cost is wayyyy higher than plywood, like hundreds instead of maybe $25 per panel, but I wonder if it might not be worth it for front/back. According to the engineer, it should not matter if the floor is of mixed material (in other words, composite front/back w/plywood middle). What do you guys think. Note: on the referenced page it does list recreational.

[Isuzusweet]

Originally Posted by 70CT

What about "Coosa" or another type of foam board or composite?

Coosa is the way to go.

Coosa Composites, LLC - Manufacture of high-density, fiberglass-reinforced polyurethane foam panels

It's 45% lighter than the equivalent plywood sheet. It just as strong and machines to shape like a dream. It's mold and mildew free, not just resistant and will not ROT!!!!!! EVER!!!. It also doesn't expand or contract anywhere near the extent of plastic or polymer based sheets.

I did a major comparison before choosing this product and decided on Coosa as it was Marine grade, would never break down and you also don't have to cover with epoxy as you would plywood.

I personally used the Bluewater 20 as a subfloor replacement on my 310 turbo diesel as the furthest space I had to span was 14".

If I were to order a new trailer from Airstream today I would buy sheets of Coosa and deliver them myself to the factory for them to put into my trailer.

Cheers
Tony

[COArgosy78]

So, regarding Coosa. What is cost on 4x8 or comparable to plywood panel? and is it distributed nationwide? Thanks.

[Isuzusweet]

The cost was $275.00 per sheet Canadian with 11 ply Marine 5/8" Meranto board being around $180.00. I wouldn't know what it would cost in your area (probably a whole lot less) and you would have to contact Coosa LLC to find the nearest distributor (probably a marina as I did). If the marina works with Coosa as mine did, they could tack on your order with theirs for reduced shipping.

I bought 3/4" material as it was in stock with 5/8" possible but not a stock size. I didn't mind that it was an 1/8" thicker than the OEM 5/8" as it created a 1/8" ledge, and since water doesn't tend to run upstream, (there are a few exceptions) it worked out just fine.

Yes it's pricey but worth every cent in piece of mind knowing that should a leak occur, I don't have to worry about it. Also should I decide to sell my coach I would get every cent back, as I could show a future owner that I used only the best materials to renovate my coach.

Would you pay more for a Coosa replaced subfloor if you were looking for a trailer or coach?

Cheers
Tony

[COArgosy78]

OK. I'm officially worn out trying to research this. Or even try to find a suitable replacement for good ole plywood in my area. Seems here in Colorado, everybody is happy w/standard plywood for subfloor work. Haven't found anyone close carrying the Coosa.
I did come across this, which I hope might come in handy for others and am trying to find the Advantech in a 5/8" thickness here in the Denver area. So far, only 3/4" is available. Anyway, see what you guys think:?

http://www.mobilehomerepair.com/phpbb/viewtopic.php?f=6&t=6670

I was also really interested in another thread here at the AS Forums that talked about Nylosheet made by a company out of Georgia. Got in touch with them and got a quote, but the cost to ship it here is as much as a sheet of the stuff! Anyone from the Georgia area taking a vacation out here to Colorado interested in hauling a couple sheets of 4x8? Can we talk?

[Tentmaker]

When using a synthetic board what are you doing about the 1/2" splices??? I've just purchased some Nyloboard and need to figure out how to splice below it. I'm buying sheets as it is the only thing I can get my hands on for months and can handle by myself. Thanks for the help!

[Isuzusweet]

Not sure what joinery method you are refering to by the term, splicing. I used a half overlap which was achieved by setting up a router with a wing cutter 3/4" larger than the bearing underneath it. Once I had the cutter cutting just a hair larger than half the board I would cut a top lap and a bottom lap leaving about 1/32 gap for sealant or adhesive.

You could buy a 1/4" wing cutter bearing bit and cut a slot in both boards and insert a nyloboard splice as well but I found the half overlap was much easier to install.

Cheers
Tony

[flygrrl]

Anybody used Densilite XP (also called boatboard)? or HDPE puck board. Both are available more easily here in Canada than Coosa or Thermolite, and are cheaper. Also the boards can be custom welded to fit over the entire trailer floor, and cut to order to your template, how cool is that?
Densilite is used for floors in pontoon boats and house boats and has a no slip texture but can be covered.
I am mulling over what to go with for our Full Monte. I know I am not going to use ply.

[Isuzusweet]

The big problem I found was expansion and contraction rate with plastic based materials. If you have ever seen a Trex deck on a very hot day after being installed in early spring without allowances for expansion, and you would know what I mean.

The Coosa board I have talked about in earlier postings is enert and stable. It will not cause problems due to temp or moisture.

The link below will put you in contact with a marina/boat shop in Meaford that regularly ships in Coosa from Nova Scotia. The shop didn't even charge me shipping on the sheets as they just tacked on my order of Coosa onto their own. Seriously it is the only way to go with no headaches.

Cliff Richardson Boats Ltd.

Cheers
Tony

[truckasaurus]

I like the Coosa samples I received a while back but I'm looking forward to checking out some MONOPAN samples when they get here. Thermal expansion is my only real concern right now. On the upside it's well used already in campers and trucking, has available fastening systems and they are happy to send me one sheet for my project, 8' 2" wide and 30' long. I can use the cut offs to make the wheel well boxes and have it all sealed up :-)

I forgot to mention it's insanely light too.

[Isuzusweet]

Originally Posted by truckasaurus

I like the Coosa samples I received a while back but I'm looking forward to checking out some MONOPAN samples when they get here. Thermal expansion is my only real concern right now. On the upside it's well used already in campers and trucking, has available fastening systems and they are happy to send me one sheet for my project, 8' 2" wide and 30' long. I can use the cut offs to make the wheel well boxes and have it all sealed up :-)

I forgot to mention it's insanely light too.

Very cool stuff. I have two concerns though.....flamability and attachment strength (will it hold a screw and or adhesive)? It will be interesting to find out your observations compared to Coosa.

Cheers
Tony

[flygrrl]

Thanks for the link Isuzusweet, Meaford is kinda far away so I am going to do some asking around at the marinas in Kingston and along the St. Lawrence. I am also checking with an industrial sign company for the expansion/contraction specs on Densilite XP. Boat builders and trucking fleets use it for flooring so I am hoping it will be within necessary specs.

[Gaël]

Hello everybody,

Thread interresting... I'm looking too the best subfloor...

If the aluminium sheets under the chassis are in good condition, without water leak, the rockwool under the wood-floor isn't sufficient ?

I've heard it was a good idea to create a ventilation system under the floor... is it right ?

Thank you

[Brasslens]

Hello! I've just purchased 5 sheets of 3/4" densolite plastic last week. It's been used for flooring, walls, gates and almost every use imaginable according to the guys at polyzone in St. Catherine's Ontario. It's pretty strong and they say it does not expand and contract. I'm going to have to add more trailer frame reinforcement to make the gaps smaller to prevent the plastic from sagging just incase. I hope to have it installed in a few weeks after I get my rear sag fixed