Montana Owners Club - Keystone Montana 5th Wheel Forum - View Single Post

freckleslettucehead · 03-08-2022, 11:22 AM

Wow, incredibly helpful--thank you all!!

So, I'm thinking of doing both things, as phillyg outlined. Lap joint in the 23/32" piece we already have, glue that together, and then add 1/8" ply over the top of that with a staggered joint. I have a few questions about the logistics of that though.

1. The total width of the floor with 23/32" + 1/8" plywood is going to be almost a tenth of an inch wider than the original 3/4" floor. Seems negligible, but want to make sure we're not going to run into problems re-installing that slightly wider floor. Along those same lines, would it be better to do 1/4" ply on the top layer, for stability? Or stick with 1/8" to most closely match the original floor width?

2. The cut we had made for the 23/32" plywood is right down the middle. If we stagger the cut in the 1/8" plywood so that it is 1/3 of the way from the slide wall, is that sufficient? I realize that ideally, we would have cut the first piece differently so that we could stagger the joints of the two layers more evenly. Is this significant enough that we should just start over with a new base layer of plywood with the cut done differently? Or can we get away with using what we have?

3. I can't seem to locate any exterior grade plywood in the 1/4" or 1/8" range. If the bottom layer is ACX (or some other exterior grade ply), can the top layer safely be interior grade?

4. Last but not least, we were told by an RV repair professional that a heavy duty tarp would be fine in place of the Darco to wrap the subfloor. Anyone have any objection to that? Can't seem to locate any Darco aside from off the internet and I don't think we have time to wait for shipping.

Thanks again! You guys are great!

03-08-2022, 11:22 AM	#7
freckleslettucehead New Member Join Date: Mar 2022 Location: Los Osos Posts: 4 M.O.C. #30609	Wow, incredibly helpful--thank you all!! So, I'm thinking of doing both things, as phillyg outlined. Lap joint in the 23/32" piece we already have, glue that together, and then add 1/8" ply over the top of that with a staggered joint. I have a few questions about the logistics of that though. 1. The total width of the floor with 23/32" + 1/8" plywood is going to be almost a tenth of an inch wider than the original 3/4" floor. Seems negligible, but want to make sure we're not going to run into problems re-installing that slightly wider floor. Along those same lines, would it be better to do 1/4" ply on the top layer, for stability? Or stick with 1/8" to most closely match the original floor width? 2. The cut we had made for the 23/32" plywood is right down the middle. If we stagger the cut in the 1/8" plywood so that it is 1/3 of the way from the slide wall, is that sufficient? I realize that ideally, we would have cut the first piece differently so that we could stagger the joints of the two layers more evenly. Is this significant enough that we should just start over with a new base layer of plywood with the cut done differently? Or can we get away with using what we have? 3. I can't seem to locate any exterior grade plywood in the 1/4" or 1/8" range. If the bottom layer is ACX (or some other exterior grade ply), can the top layer safely be interior grade? 4. Last but not least, we were told by an RV repair professional that a heavy duty tarp would be fine in place of the Darco to wrap the subfloor. Anyone have any objection to that? Can't seem to locate any Darco aside from off the internet and I don't think we have time to wait for shipping. Thanks again! You guys are great!