Floor replacement advice

[8BallManager]

Sent: 12/8/2005 12:46 AM

I am in the process of completely replacing the floor in my '72 D22C.  The existing constuction is typical - two layers of plywood sandwiching a layer of 3/4 inch foam and wood.

Which brings me to my question.  How required does everyone consider the foam component?  It seems that Winnebago used plywood and solid wood rather than the foam in areas that need more strength.  In fact, I was a little suprised by how little foam I found during the demolition.  It would seem that I would get a more solid floor if I skipped the foam entirely and stuck with wood.  Has anyone tried this approach?

And fwiw, the RV will be living in California, so I'm not worred about any loss of insulation.

Thanks,
Steve

[denisondc]

Sent: 12/8/2005 1:20 PM

   I hope you will take lots of pictures to show the rest of us - who will eventually need to replace flooring.
   I would expect the major reason to use plywood/foam/plywood in place of solid plywood might be to control weight, as much as for insulation.

[DampDude007]

Sent: 12/8/2005 2:12 PM

I could see weight/sound proofing and insulation would be my guess.
Dude

[8BallManager]

Sent: 12/9/2005 7:59 PM

The weight is a good point.  I'm sure it was part of their design decision.  In this case, the main floor (below the cab) is about 4 sheets of plywood.  At 75 pounds per sheet, there would be about 300 pounds of plywood for the inner core.  The current floor looks to be about half foam and half wood, so I'm thinking that we are talking about 150 additional pounds.

Steve

[rlm98253]

Sent: 12/9/2005 8:18 PM

Steve:

I have replaced sections of the floor in my 1974 Winnebago Expo.

The frame is made from 3" fir with lap joints, glue and screws. The face and back of the panel are 1/4" CDX exterior plywood. All exposed surfaces were coated with coal tar epoxy.

Hope this gives you some useful ideas.

Regards,

~rlm~

[Cooneytoones]

Sent: 12/11/2005 11:52 AM

for the area of the country you live in, I don't think leaving the insuation out would hurt anything as far as the isulation factor is concerned...Strengh is what is most important....Wood is not a very good insulator of hot, cold, or sound.... sound dampening, would be the only need of it in your area, but that could be solved with a little extra carpeting.  Your passengers may hear a little more road noise when in the back of the coach while going down the highway, The other negitive point I see to not using the insulation might be, wood has a tendencey, when 2 pieces of wood are placed on top of one another and fastened together, especially when they get wet and then dry, they warp ever so little, and two pieces of wood when walked on can squeek..   ...and that could be very annoying, even some new homes have this problem...   Floor squeek.. a problem home builders have been looking to solve for many years, some claim they have.....Time will tell. Remember, homes with this problem are stationary, not moving down the highway at 55 to 65 mph hitting bumps & pot holes....so insulation between two pieces of plywood might solve some of that headache too....

Just some of my thoughts,
Timmy

[8BallManager]

Sent: 12/14/2005 4:16 PM

I hadn't thought about squeaks.  Very good point.  I'm sure I wouldn't hear the end of it if I replace the entire floor, and it squeeks...

[70winnie]

Sent: 12/15/2005 1:49 PM

I completely replaced the floor of my winnie (see my photos), trying to retain the original design.

I don't know how much harm would come from eliminating the foam layer, but these would be my concerns:

(1) If you use thicker wood in place of the foam, that's a lot of extra weight.

(2) If you were to simply elimate the layer of foam, keep in mind that some parts of the floor contain 3/4" wood instead of the foam.  This extra wood no doubt provides additional support/strength, especially where interior walls, etc. are secured to the floor.  Eliminate that extra strength, you might sacrifice the structural integrity of the winnie.

How do you plan to replace the entire floor without removing all of the interior walls, etc?  The original floor works as a single unit.  If you only plan to replace the floor where it is exposed, and leave the original floor under the bathroom, cabinets, closets, etc., then the integrity of that complete unit is sacrificed.  Be very careful to secure the new floor to the unreplaced floor as much as possible.  The entire floor more or less "floats" on the chassis, bolted along the edges (and in some places, in the middle) along each 2" square cross-member.   

[8BallManager]

Sent: 12/16/2005 10:43 AM

I'm sorry if I wasn't clear.  I am completely removing the interior, including the floor and the interior walls.

I started by removing the floor, and interior components from one section of the rv.  In order to support the outer wall, I used hydraulic bottle jacks on the ground below the wall.  (It should be noted that outer was was separated from the floor when I bought the old girl a few months ago and measurments indicated that the passenger side was low by about an inch and a quarter.)  So, I jacked up the outer wall and removed a section of the old floor.

Now, if I didn't live in a neighborhood with an HOA, I would have simply used jack stands to hold up the walls while I replaced the floor.  Unfortunatly, I have to move her every 48 hours so I need to temporarily attach the the outer walls to something.

I have used 2x6's to act as a temporary support.  I ran a 2x6 along the edge of the wall on top of the 2x2 steel joists and bolted it down through the same holes that the original elevator bolts used.  Then, using the bottle jacks I made sure that the wall was the correct height.   Vertical 2x4 cleats where then added, screwed into the existing wall panelling. The lower ends of the 2x4's rest on the 2x6 and support the wall.  I then removed the bottle jacks.  I finished it off with a couple of lag bolts and fender washer from the outside (after removing the trim piece) into the 2x6 to snug the wall up.  Given the poor state of my roof and the loss of the interior supports, I have used a full height 2x4 cleat on each side and then a 2x4 ceiling joist on top of that.

So far I have all of the floor out except for the last 3 feet in the rear.  I'll try and get that done this weekend.  When complete, the box should be completely empty and supported with only a ring of 2x6's.  The chassis will be completely exposed.

It was fun to stand on the ground inside and say that 'I was up to my *ss in Winnebago'....

[70winnie]

Sent: 12/16/2005 12:29 PM

8Ball, considering how carefully you're going about the restoration, my personal opinion is that you should restore the floor to its original construction.  The reason:  you're only going to do this once.  If you add the foam, you won't feel bad saying "I don't know if I really had to."  But if you don't, you'll probably end up saying "I wish I had done it."

BTW, it seems the walls are supposed to be supported not so much by being attached to the floor, but by the steel braces that drop from the floor along the inside of the walls.  Because the bottoms of the wall panels are the worst to rot, the support fails and the walls sink (as yours did).  If I were going about a complete restoration, I would try to hollow out the foam in the walls next to the support, all the way up to the ceiling.  Then, glue a 2x3 into that space so you can reattach the support to something in the wall that actually has substance and can help support the load.  I would have done this in my Winnie, had I not learned about cause of the problem too late!