Reply
 
Thread Tools Display Modes
 
Old 08-08-2016, 10:27 PM   #1
Mini-Skoolie
 
Join Date: Aug 2016
Location: Battle Creek, MI
Posts: 28
Year: 1997
Coachwork: Blue Bird
Engine: 5.9 Diesel Cummins
Screwing into my subfloor after I just filled holes?

So, I have finished ripping out my seats, and am in the process of cleaning up the floor and going to be moving forward to the subfloor in a few days. The question is: After cleaning up and sealing all the holes from the old seats... am I really about to put more holes in this dude by attaching the firing strips? Is there a particular approach I should take (place to screw) or do I just deal with the fact the the underside is going to have "water entry" points with the new screws I put in or do I just deal with it. I'm assuming that stainless steel screw are the way to go for the sake of them not rusting, but is there any "industry standard" idea for not recreating the same problem when I attach the strips?
lanegordon is offline   Reply With Quote
Old 08-09-2016, 09:50 AM   #2
Bus Nut
 
FlyboyHPD's Avatar
 
Join Date: Feb 2015
Location: Houston, Tx.
Posts: 344
Year: 1999
Coachwork: International
Chassis: AmTran
Engine: DT466E
Rated Cap: 84
If you're going to spend any length of time in it and be in cold weather it really would behoove you to completely take out all the old flooring. That way you'll be able to see if there is any major rust on the steel floor that needs to be removed/repaired. And also will allow you to put down new poly-iso foam insulation first, and then a new plywood floor on top of that.

You don't need to put down any furring strips at all. Just create a semi-floating floor with the new insulation and plywood. If you put down 1/2 in plywood then only buy screws long enough to go into the total thickness of the plywood and no further. That way you won't be putting holes into the steel floor.
__________________
1999 International AmTran, DT466E, MD3060
http://www.flyboyrv.com
FlyboyHPD is offline   Reply With Quote
Old 08-09-2016, 11:02 AM   #3
Mini-Skoolie
 
Join Date: Aug 2016
Location: Battle Creek, MI
Posts: 28
Year: 1997
Coachwork: Blue Bird
Engine: 5.9 Diesel Cummins
Thanks for your reply.

The old floor is all out and and stripped down to the bare metal (and I have some rust repair to do for sure) 😁

I'm confused about not using furring strips. How would I attach the new play wood floor down if I'm not screwing into strips? Also, fastening down walls/ etc would be important for safety reasons wouldn't they?
lanegordon is offline   Reply With Quote
Old 08-09-2016, 11:24 AM   #4
Bus Nut
 
FlyboyHPD's Avatar
 
Join Date: Feb 2015
Location: Houston, Tx.
Posts: 344
Year: 1999
Coachwork: International
Chassis: AmTran
Engine: DT466E
Rated Cap: 84
Congrats on getting all the old flooring out and taking care of any rust. Plus it usually winds up smelling better without the old rubber floor and rotten plywood.

The floating floor concept confuses a lot of people. Make sure the new plywood you buy is at least 1/2 inch or thicker (5/8 or 3/4). And you can actually save some money by going with OSB plywood if you plan to place some type of laminate flooring on top of it.

Anyway, no strips are needed because once you screw framing lumber into the floor for any walls you are putting up those framing members will also be attached to the ceiling framing members with the studs you use. Then once you attach cabinets to the floor and then also to the side walls the floor really isn't floating anymore and will be securely held down by everything that you attach to it. Make sense?
__________________
1999 International AmTran, DT466E, MD3060
http://www.flyboyrv.com
FlyboyHPD is offline   Reply With Quote
Old 08-09-2016, 06:11 PM   #5
Bus Crazy
 
Join Date: Nov 2011
Location: Sault Ste. Marie, Ontario
Posts: 1,235
Year: 1997
Coachwork: Thomas
Chassis: B3800 Short bus
Engine: T444E
Rated Cap: 36
Yep, don't put screws through if you can avoid it (and I think you can).
I would recommend this sandwich:

1. Metal floor all cleaned up, holes filled and painted.
2. PL Premium glue. PL also makes a glue specifically for rigid foam (PL 300, I think?), but it doesn't stick to steel worth anything. I experimented with PL Premium and found that it didn't eat into the XPS foam and sticks much better.
3. at least 2" of XPS foam. No EPS or polyiso with the foil face. The foil face will do nothing when directly against plywood or steel and it is a poor surface to glue. You want foam that can withstand the compression of human bodies.
4. PL Premium glue
5. 5/8" or thicker plywood.
__________________
My build page: Armageddon - The Smell of Airborne Rust
jazty is offline   Reply With Quote
Old 08-09-2016, 08:55 PM   #6
Mini-Skoolie
 
Join Date: Aug 2016
Location: Battle Creek, MI
Posts: 28
Year: 1997
Coachwork: Blue Bird
Engine: 5.9 Diesel Cummins
What about a vapor barrier? Also, thoughts on gluing with the adhesive you listed here SOME firring strips that I could at least attach the middle seam on the plywood to? (Assuming I'll have middle seams). That way I can keep the board square from shifting (although I'll obviously try to cut them to fit tight).
lanegordon is offline   Reply With Quote
Old 08-09-2016, 09:26 PM   #7
Bus Crazy
 
Join Date: Nov 2011
Location: Sault Ste. Marie, Ontario
Posts: 1,235
Year: 1997
Coachwork: Thomas
Chassis: B3800 Short bus
Engine: T444E
Rated Cap: 36
The metal floor already is a vapour barrier. Adding another will eventually trap moisture between the metal and the barrier, which will promote rust. That's my thinking, anyhow. Also, the XPS foam is almost a vapour barrier. That's another reason not to use the foil faced stuff: the foil is very much a vapour barrier and moisture can easily get trapped between the floor and foil through capillary action.

If you use tongue and groove plywood you won't have any seams to worry about. If you put a bit more of the Pl Premium in the groove before pulling them together you will end up with one contiguous floor piece.

If I were to do it all over again this is the approach I would take. Currently my floor is metal, foam glued to the floor, T&G plywood glued to the foam then screwed down (no firring strips. very much unnecessary with XPS foam and an unwanted thermal bridge). I wish I would have skipped the screws. The screws probably don't transfer a significant amount of heat (or cold) in or out, but in the winter they do ice up. Then when the bus interior heats up there are little pools of water at the screw heads until it evaporates. The screws just aren't necessary, in my opinion.
__________________
My build page: Armageddon - The Smell of Airborne Rust
jazty is offline   Reply With Quote
Old 08-09-2016, 10:02 PM   #8
Mini-Skoolie
 
Join Date: Aug 2016
Location: Battle Creek, MI
Posts: 28
Year: 1997
Coachwork: Blue Bird
Engine: 5.9 Diesel Cummins
That makes a TON of sense. THANK YOU! I'm assuming for the fuller sheets that will work great (what direction would you run your sheets of plywood? Also, as I get up around the steps, etc., there I will like have to fasten things down (plywood wise) to a certain extent, yes?
Ooh! One more "secondary" question while I have you: How many of you rip up the flooring in and around the driver's seat? Is that typically a place of a lot of "rot" and "mess"? Mine seems solid, but it's old and the rubber flooring is kinda gross.
lanegordon is offline   Reply With Quote
Old 08-10-2016, 09:20 AM   #9
Mini-Skoolie
 
Join Date: Apr 2016
Location: New England
Posts: 51
Year: 2003
Coachwork: AmTrans
Chassis: International
Engine: T444E
Quote:
Originally Posted by lanegordon View Post
That makes a TON of sense. THANK YOU! I'm assuming for the fuller sheets that will work great (what direction would you run your sheets of plywood? Also, as I get up around the steps, etc., there I will like have to fasten things down (plywood wise) to a certain extent, yes?
Ooh! One more "secondary" question while I have you: How many of you rip up the flooring in and around the driver's seat? Is that typically a place of a lot of "rot" and "mess"? Mine seems solid, but it's old and the rubber flooring is kinda gross.
I did not rip up the small square of plywood/rubber located directly under the drivers seat. On my Am Tran this section was separate from everything else and elevated about an inch taller, with different steel flooring for the seat to bolt down to. I opted not to mess with the structural seat anchoring, especially when I found that one of the bolts would not come out as the welded nut in the floor was spinning freely.

As for the floating floor concept, I am glad I stumbled upon this thread. I am getting very close to laying down insulation and subfloor and had been planning to anchor furring strips to the metal floor with screws. After reading this I may reconsider. But not having the floor, or subsequently the cabinets etc, anchored to the floor in a moving bus concerns me. Our proposed layout and relatively open concept so there are very few walls to help anchor the floor to the ceiling. I suppose the cabinets along each side could serve to attache the floor to the walls. But I still feel like a hard slam on the brakes would put a lot of stress on those few attachment points from the whole floor shifting forward. And of course in a worst case scenario, I would think a rollover would be disastrous....

Also, is only certain foam board capable of handling the direct load with no furring strips? I haven't noticed such ratings on the products at my local home improvement stores. Is there concern of compaction over time?

Thanks
WhiteWhale is offline   Reply With Quote
Old 08-10-2016, 10:06 AM   #10
Bus Nut
 
FlyboyHPD's Avatar
 
Join Date: Feb 2015
Location: Houston, Tx.
Posts: 344
Year: 1999
Coachwork: International
Chassis: AmTran
Engine: DT466E
Rated Cap: 84
Quote:
Originally Posted by WhiteWhale View Post
It would put a lot of stress on those few attachment points from the whole floor shifting forward. And of course in a worst case scenario, I would think a rollover would be disastrous....

Also, is only certain foam board capable of handling the direct load with no furring strips? I haven't noticed such ratings on the products at my local home improvement stores. Is there concern of compaction over time?

Thanks
What you could do to keep from putting holes in the steel flooring is to attach the furring strips into the side walls. Then screw the plywood into the strips from the top.

As for the foam board insulation I've done plenty of research and polyiso works just fine and since you are putting sheets of plywood over it the load distribution and compression of the foam board is not a factor. There is also no reason to use glue on the insulation or the plywood. As long as you lay it all down wall to wall and screw the plywood down on top of it, it's not going to shift.
__________________
1999 International AmTran, DT466E, MD3060
http://www.flyboyrv.com
FlyboyHPD is offline   Reply With Quote
Reply

Tags
firing strips, floor prep

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 01:26 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.