Bowed Floors

[CREATIVERS]

Hi again. Another problem to solve. My floors sag at the edges and bow up in the middle. My wood floor at the entrance floats about a half inch over
that structural member at the bottom of the body, where I believe the wood is supposed to touch. The middle aluminum floor joist (about 3 ft behind
the steps) also sags noticeably from the frame to where it bolts to the body.
I kind of hid the problem by bolting that joist down to the frame cross-member directly beneath it. It kind of sucked the floor down flat, but it
still sags at the edges. So I certainly don't like the solution. And while I have the interior gutted, I would like to apply a better solution.
I read about one guy who braced up the outer edges by bolting a brace to the outside of the frame. But even that's a bit awkward, dodging the parking
brake cable. And I'm not equipped to fabricate my own brace.
So my first question is, can I replace the wood flooring by simply unscrewing those heavy aluminum strips on each side, that appear to hold down the
wood floor? Do I understand correctly that it is the aluminum joists that support the body on the frame, and not the wood floors? (IOW, can I remove
the wood floors without lifting the body off the frame?) Then if I get the wood out, why shouldn't I add some hefty angle-aluminum, back to back, to
act as more floor joists, and bolt them to the bottom of the body, to assist the existing joists? Then fill between them with narrower wood flooring.

Thank you again to all willing to share your knowledge and experience.
Paul


--
Paul & Carolynn Lynnwood WA
'73 23' I don't know the model. Mid-bath.
Presently gutted. Installed One-Ton FrontEnd.

 

[terry1]

Since you have it gutted, you probably can hold up the body shell with just those aluminum frames, as long as you don't have any other excess weight
up top. I would still brace it up with some type of stands so Murphy isn't tempted to invade your scene.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

 

[justin brady1]

Paul,
You can remove the floor without pulling the body.
You have to remove the wheel wells and the rear compartments to remove the floor.
The floor is glued down so it's a pretty big job to remove it, lots of prying and cursing, but it will come out.

--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455

 

[richshoop]

I believe that the material to be used for the floor is specified as 'marine' plywood, full dimension, not that sheet material from the large box retailers. Also, watch the grain as plywood flexes differently depending on the direction of the face grain.

----- Original Message -----

From: "Justin Brady"
To: gmclist
Sent: Wednesday, April 5, 2017 7:13:43 AM
Subject: Re: [GMCnet] Bowed Floors

Paul,
You can remove the floor without pulling the body.
You have to remove the wheel wells and the rear compartments to remove the floor.
The floor is glued down so it's a pretty big job to remove it, lots of prying and cursing, but it will come out.

--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455

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[CREATIVERS]

Justin,
Thanks especially for the picture. That is the best closest picture I've seen with the wood floors out. And I appreciated your articles on your
website. I will come back to that and read more.

My intention is to leave the floors in from the wheel wells back. I think the flooring there is in good enough condition, I don't see any sagging
problems, and I have already re-placed the original wet-bath back in place.
But you give me some courage to make the move to remove the two panels (on my 23') ahead of the wheels.

No one commented on beefing up the cross-members (I called them floor joists, for want of a better word), that I saw. But if I manage to remove the
floors, I will do what I have to to support the floor and the body.
--
Paul & Carolynn Lynnwood WA
'73 23' I don't know the model. Mid-bath.
Presently gutted. Installed One-Ton FrontEnd.

 

[Rdenney]

Paul, I have the same problem on mine, but have not yet been motivated to
do anything about it. The aluminum top-hat-section floor beams creep over
time, and the plywood of course creeps with it. There is not vertical room
for a stronger (as in, deeper) crossing beam, and support from the frame
needs a vibration pad like the rest of the body.

We used to call it "middle-aged spread" and assume that the body itself was
widening. That's probably happening, too. And we used to blame wrinkles in
the lower body panels on the breakdown of body pads, but I suspect in my
case it is caused by the mustache shape the floor base taken in section.

I seem to recall from the deep past that Marsh Wilkes (who, like me, seems
to be poking in from time to time of late) was constructing an aluminum
floor structure that replaced the plywood altogether. I don't know how that
turned out.

But sag is inevitable without that support from the frame. The body is
supported 10-12" inboard of the edge of the body, and so the weight of the
walls plus all that is attached to them is cantilevered out from the frame.
With only 1-1/2" or 2" of distance between the top of the frame and the top
of the floor, there isn't much depth for a structure to resist that offset
load forever.

Getting the plywood to unsag by replacement should also include
straightening those aluminum crossing beams. But I wouldn't expect that to
last without some additional support.

Rick "still ignoring this problem for now" Denney

> Justin,
>
> Thanks especially for the picture. That is the best closest picture I've
> seen with the wood floors out. And I appreciated your articles on your
>
> website. I will come back to that and read more.
>
>
>
> My intention is to leave the floors in from the wheel wells back. I think
> the flooring there is in good enough condition, I don't see any sagging
>
> problems, and I have already re-placed the original wet-bath back in place.
>
> But you give me some courage to make the move to remove the two panels (on
> my 23') ahead of the wheels.
>
>
>
> No one commented on beefing up the cross-members (I called them floor
> joists, for want of a better word), that I saw. But if I manage to remove
> the
>
> floors, I will do what I have to to support the floor and the body.
>
> --
>
> Paul & Carolynn Lynnwood WA
>
> '73 23' I don't know the model. Mid-bath.
>
> Presently gutted. Installed One-Ton FrontEnd.
>
>
>
>
>
> _______________________________________________
>
> GMCnet mailing list
>
> Unsubscribe or Change List Options:
>
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>

 

[hal stclair]

You could give it a slight body lift and straighten it out. Add a pair of angles to each cross member bolted to the aluminum cross members. You might
need to bend the member before bolting the new re enforced angles to them but with everything out as you now have it shouldn't be a very tough job.
Probably do it with 1/4" angle witch wouldn't be noticed.
Just thinking out loud.
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout

 

[CREATIVERS]

I looked up some pictures by Marsh Wilkes. He went all out with the all-aluminum floor. (Don't we wish GMC would have done that in the beginning?)
Although it doesn't appear that he addressed what seems to me to be a structural weakness, that the entire body is supported by those shallow
cross-members that cantilever out over the frame.

So yes, since we cannot add depth, it seems to me I need to add more cross-member supports. I am picturing 1" angle-aluminum, or perhaps combinations
of angle and channel. I picture spreading these evenly between the existing supports (but only between the front and rear wheel wells). I can only
guess at how many I might want to end up with. (If not for cost, I suppose I would like to fill the entire area with these supports) I would pad each
one over the frame, as I replace the existing pads.

I don't yet have a clear picture of how these supports connect to the body. Although from one picture, it looks like there is a channel in the body
structure that they fit into. I assume this will become clear as I get the existing wood out.

Then I would cut narrower strips of 1" marine plywood to fill whatever space I leave between each of these supports. Then cover the whole with 1/4"
plywood.

And perhaps I may have to also add some L-brace to the outside of the frame, under the existing cross-members, to get them straight.

Now I need to find some time. And money. And I need it to stop raining. (This is all being done outside)
--
Paul & Carolynn Lynnwood WA
'73 23' I don't know the model. Mid-bath.
Presently gutted. Installed One-Ton FrontEnd.

 

[steve southworth]

Paul - '73 floor is one inch plywood.
--
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI

 

[Daniel]

Just a thought.

Is it not possible to use a "sandwich floorplate"
Underside polyestherplate then insulation and on top marine quality plywood, all three bonded by the insulation.

This becomes very solid flooring, with the extra advantage, underside is fully waterproof, insulated and the top can be used to srew and/or glue stuff
on.
I don't realy know what kind and variations are available in the USA, but here in Europe there are many available, used in Motorhome builing.

I am sure there will be more knowligeble people here, for US sources.

Daniel
--
Daniel Jacobs, No GMC, but an admirer of them .... We'll see what the future brings ....

Always remember, the world is full of nice people!
So, if you can't find one, be one!