1973 Excella floor

[filterman]

Whats your take on replacing floor (plywood) with solid tiger wood decking tongue and groove? Input wanted.

[boatdoc]

Originally Posted by filterman

Whats your take on replacing floor (plywood) with solid tiger wood decking tongue and groove? Input wanted.

Too heavy, too soft in hot temps. Expansion and contraction concerns.
"Boatdoc"

[filterman]

Thanks Boatdoc i am gong with polyboard. Life span Up to 250 yrs Maintenance free
(All-Weather)
Welcome to New City Resources Inc.
http://www.newcityresources.com/pben.htm

[driftless]

From the General Installation page of their website:
3. When using Polyboard in a horizontal application, do not exceed a 500~600 lbs. load carrying weight (not point loading). Supports should be at a minimum of 12 centers to prevent deflection.
4. Allow sufficient spacing for the flexibility and impact resistance of Polyboard to perform properly. In a 25°F change of temperature for outdoor applications, allow a minimum gap of 1/4" between sheets. For a 25°F or 10°C change in temperature for indoor applications, allow a 1 mm gap for expansion and contraction.

How will you support it every 12" without adding significant weight to the frame?

Unless you are going to heat and cool your Airstream all the time, the temperature change of the floor is most certainly going to exceed 25 degrees, more like 50 plus degrees. How are you going to compensate for the expansion/contraction?

[Aage]

This product doesn't sound suitable for a "real-world" travel trailer application.

[87MH]

Originally Posted by filterman

Thanks Boatdoc i am gong with polyboard. Life span Up to 250 yrs Maintenance free (All-Weather)

At 3# per sq ft you are looking at about 750 lbs of it to finish the excella.

You might want to look at the plywood again.

[jsapp]

I have rear floor rot and it looks like the original was OSB. I plan to use 3/4 marine grade when I tear the old out.

[Wabbiteer]

What was provided to me as $85/sheet marine grade 3/4" was a disappointment.

Be sure to record & research the markings on edges of the pallet-stack of plywood to determine if you are getting anything more than a 7 or 8 ply furniture-grade plywood as the faces may not be marked like conventional plyboards.

When I finally had suspicions, the sheet faces were blank and edges illegible in my case . The faces were a decent grade but the inner layers were extremely soft and allowed screw-pull through.

If I had shell off and wanted something more than home-improvement grade 3/4 exterior grade I would be looking into the construction 'scaffolding' safety rated products that are OSHA acceptable to hold men at great heights.

[driftless]

Originally Posted by Wabbiteer

If I had shell off and wanted something more than home-improvement grade 3/4 exterior grade I would be looking into the construction 'scaffolding' safety rated products that are OSHA acceptable to hold men at great heights.

We replaced the deck on my father-in-law's pontoon boat with 3/4" treated plywood from Menard's and it delaminated in less than a year. My experience with that stuff is that it is basically not great....

I've also read about plywood specifically designed to be used for concrete forms. It is made with stronger bonding agents and is moisture resistant.
I'm not sure of the availability and wonder if anyone has ever looked at that type of plywood.

[filterman]

I am going to pour 16lb density foam on the floor after I flip the frame to stabilize temps and stiffen material. I will use huck bolts to fasten floor this will allow for some movement however slight.I will fill joints with sika for expansion. The temperature variations will have to be factored into the design when I reach that point but it is manageable. If needed I will add more bracing (spar style). You basically would need to think of this floor like aluminum to a degree it must move or you will have undue stress on the bolts and frame. Also a little deflection is not so bad i dont weigh 500lb and I believe they are saying do not exceed 500lb between 12 centers of spacing on eight foot thats about 500lb per ten inches between joist or 250lb every twenty inches of joist span. So this will have to be tackled in due time. Ill take a spongy floor over a rotten one anyday. Besides I have walked on a 31ft AS with this floor installed with no extra bracing or foam and it seems firm to me.

Originally Posted by driftless

From the General Installation page of their website:
3. When using Polyboard in a horizontal application, do not exceed a 500~600 lbs. load carrying weight (not point loading). Supports should be at a minimum of 12 centers to prevent deflection.
4. Allow sufficient spacing for the flexibility and impact resistance of Polyboard to perform properly. In a 25°F change of temperature for outdoor applications, allow a minimum gap of 1/4" between sheets. For a 25°F or 10°C change in temperature for indoor applications, allow a 1 mm gap for expansion and contraction.

How will you support it every 12" without adding significant weight to the frame?

Unless you are going to heat and cool your Airstream all the time, the temperature change of the floor is most certainly going to exceed 25 degrees, more like 50 plus degrees. How are you going to compensate for the expansion/contraction?

[filterman]

Originally Posted by 87MH

At 3# per sq ft you are looking at about 750 lbs of it to finish the excella.
You might want to look at the plywood again.

Good point but what would plywood weigh and what would be the difference in that total.. Oh here ya go.
Answers.com - How much does a three quarter inch thick sheet of 4 X 8 plywood weigh
So 500 lb of plywood or 750 of plastic I take the added weight evenly distributed over the entire frame. thats about one pound per foot added weight.

[filterman]

Its already been installed in an airstream and I have walked on it. Its been down for a couple of years without problems. Whats not suitalbe is having to remove your shell to replace a rotten floor AGAIN, and all wood rots eventually. I dont ever want to tear this thing apart again. Well we will find out in due time how my ideas work. I keep an open mind and reach for the best I can do.

Originally Posted by Aage

This product doesn't sound suitable for a "real-world" travel trailer application.

[filterman]

Ok I screwed up before in my calculations trying to cook late dinner and think at the same time so here we go again. If we are spaced every 12" on center and that spacing can handle 500-600lb of load (when would you ever do that in an AS) then 24"spacing would support 250-300 lb of load right. Ok then add 16lb foam we have decreased our delfection by al least 70% with one inch of 16lb density foam and therefore we would be at about 425lb load between 24" centers. This is the idea. Or add spars to shorten distance between frame members where applicable. Remember we are just walking in a small footprint in the AS. All things are possible with enough help and thought.And yes I know I will be adding weight wth the foam 16lb for every twelve sf. Between the foam and the floor, the trailer will be about 500 lb heavier. I will be lightening her up to compensate though. About two lb per spuare foot added weight. I think I can shed about 100-150lb between the lighter ac and fans and electrical and remove the cord recoiler and go with aluminum wiring with proper al to cu connectors.

Originally Posted by filterman

I am going to pour 16lb density foam on the floor after I flip the frame to stabilize temps and stiffen material. I will use huck bolts to fasten floor this will allow for some movement however slight.I will fill joints with sika for expansion. The temperature variations will have to be factored into the design when I reach that point but it is manageable. If needed I will add more bracing (spar style). You basically would need to think of this floor like aluminum to a degree it must move or you will have undue stress on the bolts and frame. Also a little deflection is not so bad i dont weigh 500lb and I believe they are saying do not exceed 500lb between 12 centers of spacing on eight foot thats about 500lb per ten inches between joist or 250lb every twenty inches of joist span. So this will have to be tackled in due time. Ill take a spongy floor over a rotten one anyday. Besides I have walked on a 31ft AS with this floor installed with no extra bracing or foam and it seems firm to me.

[boatdoc]

Originally Posted by driftless

From the General Installation page of their website:
3. When using Polyboard in a horizontal application, do not exceed a 500~600 lbs. load carrying weight (not point loading). Supports should be at a minimum of 12 centers to prevent deflection.
4. Allow sufficient spacing for the flexibility and impact resistance of Polyboard to perform properly. In a 25°F change of temperature for outdoor applications, allow a minimum gap of 1/4" between sheets. For a 25°F or 10°C change in temperature for indoor applications, allow a 1 mm gap for expansion and contraction.

How will you support it every 12" without adding significant weight to the frame?

Unless you are going to heat and cool your Airstream all the time, the temperature change of the floor is most certainly going to exceed 25 degrees, more like 50 plus degrees. How are you going to compensate for the expansion/contraction?

Hi Driftless;
How did you get above information? I have contacted the manufacturer with that request few times and never got a reply. I, from the start of the Polyboard/Nyloboard discussion on the forums have wondered about expansion rate and load capability. Thanks to you, we now have facts. As for filterman, he is capable of finding a way to allow for expansion and contraction. He will only need to find aluminum 'Aircraft Grade' sheet metal screws and some Titanium support grid. Thanks, "Boatdoc"
: brows::b rows::br ows:

[driftless]

Boatdoc,

I went to the website that is linked above and clicked on their general installation guide.

[filterman]

YOur a smart person I know it, So how would you do it? Tell me how to make it work, cmon this is the whole point of the forums. How to make an idea work, maybe add this or add that becasue of this. I thought that was the point. It is my opinion to help others with an idea and then allow them to make a judgement based on those ideas or to add more constructive reason as to the negative aspects (with an added solution), not ridicule; but say "ok that could be done" and this is how I would do it. I dont mind teasing every now and then but at some point it does get in the way of accomplishing the task at hand.

Originally Posted by boatdoc

Hi Driftless;
How did you get above information? I have contacted the manufacturer with that request few times and never got a reply. I, from the start of the Polyboard/Nyloboard discussion on the forums have wondered about expansion rate and load capability. Thanks to you, we now have facts. As for filterman, he is capable of finding a way to allow for expansion and contraction. He will only need to find aluminum 'Aircraft Grade' sheet metal screws and some Titanium support grid. Thanks, "Boatdoc"
: brows::b rows::br ows: