Mounts for roof deck and solar

[daveola]

I'm thinking about mounting some things to my MCI 102A3 roof such as a deck and PV panels and possibly solar water.

My initial thought was to cut into the roof and weld tubing into the roof beams near the sides of the bus and then mount a platform on that for the deck and solar, but it seems like that would be tricky to patch back up and seal from water.

So, now I'm thinking I might want to use some sort of footpads like Sean talks about that I simply bolt through the roof into the roof beams.  I figure I can make some metal supports that sit on rubber sheets which I bolt through, but I'm wondering if that'll be strong enough to hold the weight of a roof deck (+ people).

I was surprised to hear that Sean's deck only uses four such feet - so that's comforting, but I wonder how strong a few screws into the roof beams will be  - and if punching a hole into the beams weakens them considerably.

Any thoughts on how to generally attach weight-bearing things to a curved MCI roof?

[JackConrad]

Most of the weight is bearing straight down onto the roof framing, so about the only load on the screws is the amount of shear load created by wind drag when driving. To calculate the load on the roof framing you will need the weight of the platform plus the expected weight of people that will be on the deck (which will depend on the size of the deck).  Jack

[gumpy]

I've been considering this for some time. I want to eventually put a deck and solar panels on my 9. My plans currently call for using aluminum angle iron to run lengthwise along the bus, out near the edge. I will remove a single rivet over each frame member and rivet the angle to the roof using the existing holes. Seal each rivet with butyl caulk. Water should be able to drain under the angle where the panels overlap. Then, build up from the angle iron. Either weld or bolt the superstructure to the angle.

[Singing Land Cruiser]

We also have been thinking of a deck on our 102a3, 8x16 ish. We would love to see how others did it. M&C 

[daveola]

Hi Gumpy!  Just saw your site recently and love the content on it.

My plans currently call for using aluminum angle iron...
..I will remove a single rivet over each frame member and rivet the angle to the roof using the existing holes.
...Either weld..

I like the idea of removing rivets and using the existing holes, I think I'm going to steal that idea.

I suppose you could also use spacers at the rivet holes, but then all your weight would be on the spacers.

Then again, this might be better then trying to put weight on the roof where the frame members are not - I can imagine some creaking would unsue if the angle iron flexes much at all.

I presume you are planning on pulling the angle iron off if you weld, or do you have some way to protect the roof paint from the heat?

[Jeremy]

Items on my roof will be mounted to lengths of steel angle that I've welded to the side of the existing roof beams in various places - I've done it this way to avoid drilling into the roof beams themselves, which I didn't feel was satisfactory for a number of reasons.

Re-using existing rivet holes is a good idea if you have them - mine doesn't as the skin and roof is bonded.

Jeremy

[gumpy]

Hi Gumpy!  Just saw your site recently and love the content on it.

My plans currently call for using aluminum angle iron...
..I will remove a single rivet over each frame member and rivet the angle to the roof using the existing holes.
...Either weld..

I like the idea of removing rivets and using the existing holes, I think I'm going to steal that idea.

I suppose you could also use spacers at the rivet holes, but then all your weight would be on the spacers.

Then again, this might be better then trying to put weight on the roof where the frame members are not - I can imagine some creaking would unsue if the angle iron flexes much at all.

I presume you are planning on pulling the angle iron off if you weld, or do you have some way to protect the roof paint from the heat?

Nylon spacers would be ok if you have long enough rivets, or you can use some other type of fastener (screw, bolt, etc). That would allow drainage under the angle mounts. You want the load distributed to the bus frame members as much as possible. I would attach the deck superstructure to the angle directly over the frame members. There shouldn't be any creaking of the roof panels that way even without the spacers as the load will be transferred directly to the frame.

I would probably pull the angle and weld it off the bus, though I might tack some brackets to get the proper angle as the slope of the roof is not
flat on the far outer edges. I have not evaluated if it will be possible to locate the angle mounts closer to the centerline and get a flatter surface, but I suspect it probably is, so might be able to do that.

It may be easier to simply bolt the superstructure to the angle supports. Easier to line things up that way.

My intention, should I ever do this, is the build rails that pivot and fold down into grooves in the deck, or at least flat on the deck. Then, when you arrive, it's a simple matter to raise the rails from the deck and pin them in place.

I think a deck and solar panels would reduce solar radiation heat buildup inside the coach, improving a/c efficiency. It could severely affect the aerodynamics of the bus, though, if not careful. 

[JackConrad]

I think a deck and solar panels would reduce solar radiation heat buildup inside the coach, improving a/c efficiency. It could severely affect the aerodynamics of the bus, though, if not careful. 

I am sure it wouls reduce heat absorbtion.  That would be very similar to the "double roof" Saudi MC-5s.  Jack

[daveola]

...steel angle that I've welded to the side of the existing roof beams...

Did you remove any of the roof to do that??

[daveola]

..as the slope of the roof is not flat on the far outer edges.

Oh right - you have an MCI9 with a somewhat flat roof.  I have a 102 with the curved roof, so it's even worse.  I figure I'll probably do four angle brackets (two on sides, two closer to the middle) with the risers on the side brackets up to the deck.

..build rails that pivot and fold down into grooves in the deck,..

Ooh, I like that - I was going to do folding rails, but I hadn't though about getting it to lie inside the actual deck.

It could severely affect the aerodynamics of the bus,..

My feeling on this is that as long as the deck is a reasonable flat shape and secure that it doesn't really effect aerodynamics.  It can't be that comparable to the front of the bus, which is similar to trying to push a barn door down the freeway (it would be amusing to mount a big nosecone on the front of the bus.  )

I suppose some sort of fiberglass scoop in front of the deck would help, like you would find on a semi, anyone ever try to mount one of these to cut down on wind?

[Jeremy]

...steel angle that I've welded to the side of the existing roof beams...

Did you remove any of the roof to do that??

No - so the angle brackets is only welded along three edges as the top couldn't be accessed. To compensate the brackets are longer than would otherwise be the case to give plenty of attachment area - obviously they will be hidden by the ceiling panels so you can make them as tough and ugly as you want.

I mounted the brackets flush with the top of the roof beams, but that is 1/8" or so below the aluminium roof skin due to the thickness of the sealant / adhesive that glues the roof skin in place. This meant there was no risk of burning holes in the skin whilst welding, but this might be a risk if your skin is riveted tight to the beams. I shall have to make up a 1/8" gasket of some sort to go on top of the brackets when I am ready to bolt things to them - but that's no problem

Jeremy

[daveola]

I mounted the brackets flush with the top of the roof beams, but that is 1/8" or so below the aluminium roof skin...

Ah - so your angle brackes are inside the bus, under the roof skin - and you're going to put holes in the roof to bolt to the angle brackets under the skin.  Is that right?  I believe that gumpy is talking about attaching angle brackets on top of the roof, which is what I'm thinking of doing...

[Jeremy]

Yes, I'm talking about brackets beneath the roof skin, to which items on the roof will be bolted via bolt holes in the skin itself. Sorry if that wasn't obvious

Jeremy