"Skylight" for standard 14"x14" roof hole (removed Air-con)
Posted: December 14th, 2015, 12:04 pm
I removed the air-conditioner from my roof around a year and a half ago. I don't have a need for it, but I removed it such that it (or another one) could be reinstalled. This left the question of what to do with the hole. Since a few people have PM'ed me about this, I thought I would share what I did.
To start, I'll mention that the hole for a typical RV roof air-conditioner is the same standard 14" x 14" hole that a typical RV vent fits into (clever!).
When I removed the Air-con, I wasn't sure what my ultimate plan would be. Options included putting a solid fiberglass panel over the hole, putting a solar panel over the area, putting in a marine hatch, putting in an RV roof vent, or...?
So as a "while I think about it," I cut a square of galvanized metal (heavyish roof flashing, comes in a sheet of about 30" x 36" at Home Depot) that was about 19" x 19" (for good overlap) and laid down a perimeter bead of strips of (good) butyl tape, running two beads wide and staggering the corner joints. I then laid the galvanized sheet down and rollered around the perimeter. Done and water tight for the year it was up there (including six months in the Pacific Northwest, so there was plenty of rain).
On the inside, there were some wires in the hole. For the Air-con, one piece of Romex type AC wire (comes over from area above stove, through loom in roof), one Cat 5 type cable and one thin wire (for thermostat, came through roof in loom from overcab area near solar controller). They also ran some DC wire that just "happened" to also go through the hole area (the Air-con doesn't project down in the entire hole area, although it covers it all from above). There is a pair of red/white (positive/ground) DC wires that come up through the roof in loom from the main driver's side wiring run that is outboard of the upper cabinets. It starts over about the center of the couch (fore/aft), and runs over to "the hole." In the hole, it splits two ways. One set of red/white go aft, to the ceiling light near the kitchen (in carpeted ceiling), and the other set go forward to the ceiling light and then to the Fantastic vent. (The ceiling light by the door is on the same circuit but that wire comes from over the door).
For the time being, I just used wire ties to "tame" the wires, and then cut two layers of 1/2" extruded polystyrene insulation and friction fit it into the hole. Then I got a piece of foam board (artist type) from Hobby Lobby (happened to find one with a grey "faux something" pattern that just matched the ceiling carpet), put some adhesive "hook" Velcro on it, and stuck it to the ceiling. That covered up not only the hole, but also the flat spots, etc. in the carpet from the Air-con inside section. So that got me tidy looking, insulated, and water-tight. I went with that for around a year while I noodled options. Here is a shot with the wires and insulation in place. The bottom of the photo is the passenger side of the Chinook. So the "bottom" wires are the Air-con related wires, and the "top" wires are the unrelated DC wires.
And here is a not-very-good-but-gives-you-the-idea of the foam board velcroed in place. Stayed up just fine for a year, with no signs of going anywhere. Boy, I can't wait to do something about that yellowed Fantastic Vent. I have already painted those "fake wood" strips on the Thin Lites (there is a thread where I posted about it). [Edited to add: Since taking this photo I used some oxy type carpet cleaner on the inevitable dirt spots in the carpet that coincide with the Air-con outlets. So no more grunge look on the overhead carpet.]
And here is the flashing on the roof. (The blue tape you see in upper left is where I removed the TV antenna, then filled the holes with epoxy. You can't paint or gelcoat epoxy until it has cured for some time, yet until then it is sensitive to UV, so I put tape over it while it finished curing - it's already totally hard and waterproof, but needs some weeks/months for the epoxy to finish so the paint or gelcoat won't react with it.)
To start, I'll mention that the hole for a typical RV roof air-conditioner is the same standard 14" x 14" hole that a typical RV vent fits into (clever!).
When I removed the Air-con, I wasn't sure what my ultimate plan would be. Options included putting a solid fiberglass panel over the hole, putting a solar panel over the area, putting in a marine hatch, putting in an RV roof vent, or...?
So as a "while I think about it," I cut a square of galvanized metal (heavyish roof flashing, comes in a sheet of about 30" x 36" at Home Depot) that was about 19" x 19" (for good overlap) and laid down a perimeter bead of strips of (good) butyl tape, running two beads wide and staggering the corner joints. I then laid the galvanized sheet down and rollered around the perimeter. Done and water tight for the year it was up there (including six months in the Pacific Northwest, so there was plenty of rain).
On the inside, there were some wires in the hole. For the Air-con, one piece of Romex type AC wire (comes over from area above stove, through loom in roof), one Cat 5 type cable and one thin wire (for thermostat, came through roof in loom from overcab area near solar controller). They also ran some DC wire that just "happened" to also go through the hole area (the Air-con doesn't project down in the entire hole area, although it covers it all from above). There is a pair of red/white (positive/ground) DC wires that come up through the roof in loom from the main driver's side wiring run that is outboard of the upper cabinets. It starts over about the center of the couch (fore/aft), and runs over to "the hole." In the hole, it splits two ways. One set of red/white go aft, to the ceiling light near the kitchen (in carpeted ceiling), and the other set go forward to the ceiling light and then to the Fantastic vent. (The ceiling light by the door is on the same circuit but that wire comes from over the door).
For the time being, I just used wire ties to "tame" the wires, and then cut two layers of 1/2" extruded polystyrene insulation and friction fit it into the hole. Then I got a piece of foam board (artist type) from Hobby Lobby (happened to find one with a grey "faux something" pattern that just matched the ceiling carpet), put some adhesive "hook" Velcro on it, and stuck it to the ceiling. That covered up not only the hole, but also the flat spots, etc. in the carpet from the Air-con inside section. So that got me tidy looking, insulated, and water-tight. I went with that for around a year while I noodled options. Here is a shot with the wires and insulation in place. The bottom of the photo is the passenger side of the Chinook. So the "bottom" wires are the Air-con related wires, and the "top" wires are the unrelated DC wires.
And here is a not-very-good-but-gives-you-the-idea of the foam board velcroed in place. Stayed up just fine for a year, with no signs of going anywhere. Boy, I can't wait to do something about that yellowed Fantastic Vent. I have already painted those "fake wood" strips on the Thin Lites (there is a thread where I posted about it). [Edited to add: Since taking this photo I used some oxy type carpet cleaner on the inevitable dirt spots in the carpet that coincide with the Air-con outlets. So no more grunge look on the overhead carpet.]
And here is the flashing on the roof. (The blue tape you see in upper left is where I removed the TV antenna, then filled the holes with epoxy. You can't paint or gelcoat epoxy until it has cured for some time, yet until then it is sensitive to UV, so I put tape over it while it finished curing - it's already totally hard and waterproof, but needs some weeks/months for the epoxy to finish so the paint or gelcoat won't react with it.)