Adding BR A/C to Styrofoam insulated roof

I believe you need to cut back the Styrofoam and build/insert a wood frame in-between the roof and ceiling. When the AC is mounted the bolts go up through the roof and are tightened from below. They need to be tight and you can't compress that Styrofoam enough to get it tight. You need to be able to clamp down on wood. If it is loose, water will come in where the AC contacts the roof (at the gasket).

I added the 13,500 BTU Air Conditioner OPTION on my OFF-ROAD POPUP when I got it in 2008. They added these two braces on both sides of the Air Conditioner like shown here in this google image photo.

My ceiling is 1/4-plyboard - then foam filled - then the roof. Only a couple of inches thick...



You could probably get a good answer by dropping into any RV dealer that installs things with their sales.

We thought about doing the same thing with our 5th wheel but finally decided we didn't think having the Air Conditioner that close to us while we were sleeping in the bed just a couple of feet below the A/C would be a good idea... Probably get a head cold every time we turned it on - let alone all of the added noise it will give us being that close.

We have the fantastic fan in this area just above our heads in the bedroom...

Roy Ken

I thought the fantastic fans were 12v if so then the wiring for the fan will not support a a/c unit.

Our 5ver was factory prepped for a bedroom AC. We replaced the vent with a MAXXFAN. I did see bracing and it was wired (neatly tied off)for 110VAC. If you don't see any of that, I won't rely on Styrofoam.

Must be a light model camper.

The Styrofoam will not support a 100 pound AC.

I can't answer the specific question, but most of the time the factory will reinforce the area around the bedroom vent to hold the weight of the AC. If this had been done you would most likely have had factory wiring in the ceiling also. Good Luck