Mounting Rooftop Air Conditioning Unit

[BigBusParts]

Howdy!

I'd like some feedback on mounting a rooftop A/C unit on a 1990 Bluebird TC2000. My concern is that the
roof doesn't appear sturdy enough to support the dynamic loads generated by the air conditioner's 95 pounds, since there are only lateral ribs spaced at about 28" where I'd like to mount the A/C. All the posts I've found only reference cutting a hole in the roof and bolting down the A/C--I couldn't find any references to reinforcing the roof's structure beyond placing wood blocks between the inner and outer roof panels to prevent them from squeezing together when the mounting bolts are tightened. It seems that spanning between the lateral ribs with a steel frame would be appropriate, but I can't see how to attach that frame to the ribs without removing the sheet metal from the interior roof. If nothing else works, I could modify the emergency exit hatch hole, but I'd like to leave that intact for another use.
Any advice from those who have done this before (or links to threads explaining the process) would be greatly appreciated.

Happy Trails!

 

[Hvbuzz]

I think you're over thinking about it like I did. I worried about it for quite awhile, untill I cut the hole, and had the AC unit sitting on the roof. I did exactly what you were saying, spaced the unit inbetween the lateral ribs. Cut a 2x2 and then 1/2" oxboard for a spacer inbetween the outer roof and the ceiling of the buss, for a total of 2" spacer. I thought at first I might need a better bracing too, but felt after having everything up there it doesn't. My spacer is actually only being held together by the AC unit. After it is all together I have no more worries, really. Its that easy.

 

[keith-SKO]

i just instal one on my 94 tc2000 ,just remember to put a few pices of hardwood between the the roof and the celling,if its a 14x14 hole you need two 14'' pices and two 16 '' pices, cut them to be 3 1/2 wide and stand them up,,,like you makeing a box.






keith

 

[lornaschinske]

If you are talking about an RV roof mount A/C unit.... I have one on my decrepit 30 yo Class C. The roof is 2" thick foam sheathing insulation, sandwiched between a thin layer of luan, and topped off with a really thin aluminum skin on the roof. If a sticks-n-staples RV can handle one on the roof, then a skoolie most certainly can as well.

 

[Diesel Dan]

Intuitively it doesn't seem like a solid mounting, but many people on this site (including myself) have mounted their AC this way and have been driving around for years with no problems.

 

[BigBusParts]

Thanks, for the advice, Guys!

I cut my 14" hole today, and if all goes well, should have the A/C mounted and the wires ready to hook up tomorrow! One more question: Should the gasket be installed with the sticky side up (towards the air conditioner) or down (towards the roof)?

Happy Trails!

Joe K.

 

[putterspitt]

find a sunroom installer and get a small piece of 2" foam from him, it fits perfect between the layers and is very strong, you can actually walk on 3" panels that have the alum on them

 

[BigBusParts]

Hello!

Thanks for all the excellent advice!

I made the wooden spacers that run longitudinally long enough (about 25-1/4") to extend from rib to rib, then made the shorter spacers (14") to run crosswise between them. I now have a large "H" frame around the hole that extends to the forward and rear ribs, making a very stable base for the air conditioner. I'll use construction adhesive to glue the frame in place just before I put the unit on top, then clamp it all together with the mounting bolts. I don't think that air conditioner is going anywhere the bus doesn't!

Happy Trails!

Joe K.

 

[james843]