I've read through the threads on this but didn't really see a concensus... Now it is time to go buy replacement for the sorry plywood that is my current subfloor. Should it be two layers: 1/2" homasote topped with1/2" plywood, or should I do just 3/4" plywood and coat the bottom with some kind of waterproofing? Or is 1/2" enough? I guess my main concern is making it sturdy enough that it doesn't mush when I walk on it. I so appreciate all the suggestions you guys have!
This was a tough one for me too. I completely removed the flooring so spent several weeks researching an alternative to put back in...and found few options. I was hoping to find some sort of light weight, but inflexible "plastic" product -- kind of like the decking material that is popular now, but in sheets that did not cost an arm and a leg. I did not find such an option and went instead with 3/4 inch plywood, coating the bottom and sides with an oil-based waterproofing stain. I laid aluminum-backed roof seam sealer between the joints as added protection. My thought is that I still want to spray the underside with truck bed liner as an added moisture precaution, but I have not yet done that. I cut the plywood so that all of the seams fell across the beams on the frame of the trailer. I have built everything on top of this subfloor and have had 4 or 5 adults in my 14' '60 Airflyte and can report that the floor did not feel spongy at all -- I am very happy!
Marine grade plywood could be an option. 1/2" I'd think should be adequate if the original was in service for 30 years, you can always add some extra bracing, however for the extra cost of 3/4" I guess it could be piece of mind... So I will split the difference and suggest 5/8".
I used 1/2", but added a few extra frame pieces anywhere the run was long enough to feel sag. I also added frame doublers everywhere there was a seam, so that each plywood sheet had a full 1 1/2" to be screwed to, instead of just the 3/4" it had when two sheets shared one frame piece.
After doing the Airflyte Im currently working on I have decided when I get to my Astrodome I will be moving into a 3/4 floor.
Not only that but I am also going to restructure the roof front and rear wall framing up to 2 by instead of the 1 by framing originally. The side walls will remain 1 by. It will require some significant alterations but at least my roof wont be sagging from the weight of air
How much weight difference between a sheet of 1/2 and a sheet of 3/4 combined with a dozen 7ft 2by 2 instead of the original 1by maybe 100lb total ? whatever it is it aint much
Didn't try to verify it, but found this with a quick search: "3 pounds per square foot per inch of thickness according to APA Plywood Design Specification" And for whole sheets: "20-25 pounds per 1/4" of thickness"
Hamlet's original was 1/2", we replaced it with the same and coated it with waterproofing. We used a little more than one sheet. No extra bracing, but a Compact has a lot less floor space than the Airflyte, so it may not be as much an issue. Although 25 or 50 pounds doesn't seem like a lot, when you're looking at it as a percentage of the total weight of a Compact trailer, it is a statistically significant difference.
Post by Gone Kayaking on Sept 9, 2012 13:50:40 GMT -5
I did two layers with the seams overlapping on the front and back, the middle is still original. Which is why I decided to stick with the orginial material. *one 3/8 homasote facing the road (with butyl flashing--like the kind for windows). *one 3/8 inch plywood coated with watersealer.
I figure if the original homasote lasted 50+years, this should be fine. It does provide apparently some level of insulation. It is moisture and pest resitant. So it will dry out if it gets wet instead of rotting--or so I am told.
After a year and 10,000 miles of road exposure it is holding up good as new. I do plan to add truck bed liner spray on the bottom, though I am not completely convinced it's necessary.
1956 Shasta 1500
Can't wait to go campin'
Joecamper, I am in the process of rebuilding my 64' Shasta Airflyte trailer . When I do get to the point of installing the ceiling cross members I will have some sheet metal channel made to wrap the 1x2 and add screws to the sides which it will act as stiffener. A light gauge of galvanize will do. I don't think you need to use bigger material.
What question did I ask? Now that you mention that, couldn't you use carriage bolts to attach the walls to the frame and the screw nails for the paneling to the frame. I was thinking of using 1/4" crown staples at all paneling seams and ceiling edges and silver nail screws in the field. Then cover all seams with a solid birch molding like screen molding 2 edges eased over. Let alone the 200' of welting I have to install. Its going to the powder coating tomorrow. I am using a silver color like most car colors. I had a friend to plasma cut 2 ea 1-1/2"receivers in the rear 3" channel bumper. They are 2' apart from center and it will look like a triangle coming to a point for the spare tire and then have a receiver coming out of the top behind the tire for a bike rack which will be removal and the spare will always be there below the window without blocking the tail lights. I also could put a flat rack on the back for a small generator or firewood. But that would have 2 receivers on receivers without taking the spare tire off. I am going to use 3/4" marine plywood for $64 a sheet. Marmoleum flooring 3120 /Rosato color sheet vinyl Approx. $650. 3 days to get it