Roof air conditioner seal replacement

[jvf]

Sent: 3/21/2002

I would like to re-seal my air conditioner unit.  The previous owner caulked all around the perimeter of the unit but I don't think this is correct.  There must be some place for the condensation to drain.  I think it is being trapped inside.  I have a Coleman unit on a 72.  Anybody have experience removing and re-sealing the A/C?
Thanks,
Jim

[DEL]

Sent: 3/21/2002

The roof top air conditioners are unbolted from the inside.  Then it can be lifted off.  This will be easier with two people.  There is a ready made seal that goes between the air conditioner and the roof.  It can be purchased from any rv dealership. 

Note;  From time to time the bolts that attach the a/c (inside rv under shroud) will need to be tightened a little.  They will leak if they get loose.

[Oz]

Sent: 4/27/2004

Can these seals still be gotten for our old air conditioners?  How about using Eternabond tape instead?  Any suggestions?

[77surveyor]

Sent: 4/27/2004

most air conditioners seem to be the standard 14x14 same as the roof vents the replacement gasket is a thick heavy foam with a sticky side that attaches to the a/c unit  some kits come with a extra support strip that goes on the back side to kinda keep the unit leavel i just paid $15 for my set if the kit doesn't come with the leveler they will charge you extra for it    good luck    richard

sorry forgot to add the condensation drains are on the back  side underneath the unit and just drains onto the roof they do sell a diverter kit to send the water over the side but they seem to get algae in them a plug them up if your unit is sitting totally flush with the roof like mine was the condensation can only go into the motorhome making a mess when you replace the gasket set it will keep the unit about 1 to 2 inches above the roof  richard

[Oz]

Sent: 5/31/2004 
 
I got my seal.  Do I need to use a sealant between the seal and both the roof and air conditioner surfaces?  If so, what kind?  Silicone caulk?  Blue RTV?  Bubble gum?  The kid's hair gel?

I was planning to paint around the A/C with the Kool-Seal patch material.  It's basically the same as the roll-on but a thicker consistency to use around vents, on seams, edging, etc.  I will be re-coating the roof soon too and I recall from another thread that Kool-Seal doesn't stick to silicone.

[denisondc]

Sent: 5/31/2004

Some people say there is no need to use any sealant, that the seal that comes with the a.c. is all that is necessary. when the RV place installed my new a.c. they used enough extra sealant to be visible from 100 ft away. I dont know what kind it was. Maybe this was due to them knowing that winnebago flat roofs usually sagged, and the sealant would be holding back a full time water pool. Anyway, mine doesnt leak as far as I know. Also I park it at a tilt when it is not in use.
In other words, I dont know. And not much sticks to silicone products, but it sure seals aluminum seams pretty well.

[Oz]

Sent: 6/17/2004

I got the Duo-Therm A/C removed from the WinneBeast.  Heavy sucker!  Took all day to clean the sealant and roofing pitch off it and the base plate.  I noticed that there was a thick, dense, very pliable gasket of sorts used to seal the whole thing.  Not foam.  It was like a rubberized tar.  Thick stuff!  I doubt anything could ever get through that.  It looked like it was pre-formed, not applied with a caulking gun. 

The foam seal looks like it goes around the edge of the mounting plate, now that I'm looking at it.  Does that go under it and the roof or, on top of it, between the plate and the A/C unit?  Either way, I'll need to add caulking on the side that doesn't have the seal, won't I?  Where does the condensation drool out onto the roof from... exactly?  I don't want to block the flow.  What sealant has anyone used that has stood the test of time?

[DanD2Soon]

Sent: 6/17/2004

Seal goes between the baseplate of the A/C and the roof.

Adhesive on the seal is just a convenience to "stick" it to the baseplate while you have the A/C unit out of its' hole and probably lying on its back - once the seal is stuck to the unit, it's much easier to put the unit back in without pinching the seal or otherwise screwing it up.

In theory - If your roof is clean, you shouldn't need any other caulk or sealer - the weight of the unit and the cinching down of the mounting bolts should compress the seal to the point that no water can get through. Not being one to trust "theory" very far, I went a couple of steps further while I had our unit out.
First - My roof had sagged some, (enough so that the outer edges of the baseplate almost touched the roof and a PO had caulked around the outside of it just like happened to jvf.) so while I had the unit out, I cut a "picture frame" out of 1x6 treated lumber with inside dimensions the same as my hole - 14"x14" - I left the inside two inches of the "frame" the full width of the lumber (to set flat under the seal) and tapered the rest down to about 1/4" at the outside edge. I slid the frame pieces in above my roof rafters and below the roof metal and secured them with a few 2 1/2" screws from inside the coach about an inch from the edge of the opening. (the interior A/C grill covers this part of the ceiling awayway.) The result was that the frame raised my A/C unit about 3/4" and tapered the roof pitch down away from the unit seal all the way around making it really hard for the condensate to go anywhere but away from the unit and its' opening.
Second - After spending a lot of time cleaning the old caulk and "stuff" off that section of the roof while the unit was out, I put a band of 6" eternabond tape on top of the newly cleaned roof all the way around the new tapered "pedestal" letting the A/C seal set right down on it.

My Duo-therm ('72) has 4 or 5 3/8" drain holes in the unit baseplate that are 4 to 6 inches outside the seal area and let the condensate out onto the roof depending on which way the coach is tilted or the wind is blowing.

Performed this surgery 2 years ago - all is fine aboard the 2 Soon still and it makes no difference whether she's parked on an angle or true & level.

Hope this helps,
DanD

[Oz]

Sent: 6/17/2004

Great idea on the frame!  One thing I'm not quite getting though is... there is a separate plate between the A/C unit and the roof.  It's like a pan.  I'm understanding that the foam gasket goes between the pan and the roof and then the A/C unit is placed on top? 

When I removed the unit, there was this sealant stuff both between the pan and the roof and the pan and the A/C unit.

I think I'll go with the Eternabond tape.  I know it lasts.

[DanD2Soon]

Sent: 6/17/2004 

That pan is what I'm calling the "baseplate" - on ours it never came apart & I didn't try to separate the Pan from the unit proper. If we're talking about the same thing, the screws that hold the shroud/cover on thread into the "turned up lip" around that pan/baseplate.

Gotta credit Bill Laudeman for tipping me off to eternabond - Not cheap, but,I love the stuff - you'll never catch me without a roll of it aboard. Almost every roof seam on the 2 Soon has a "security strip" of eternabond tape over it and I used 20 3" squares of it under each of my solar panel feet as weather seals before screwing the brackets into the roof panels.

Later,
DanD

[Oz]

Sent: 6/19/2004 

I checked at a very large, local dealer today to see if they carried Eternabond... if you can believe this... they don't!  I didn't see it at Lowe's where I they have all the canned Kool-Seal products but, I'll call to make sure.

The dealer suggested a couple things they do carry though:  Butyl tape, putty tape, and metal roof silicone.  It sounds like a list of best to cheapest.  I would think the Butyl tape would be closest to Eternabond and silicone wouldn't last anywhere near as long on roof fixtures.

I plan on getting the Eternabond because I know it is the best through member testimony and from physically checking it out in use over time on another rig.

I'd like some feedback from members who have used all the various types of sealants as to their effectiveness, durability and price.

I can tell you that the cheap, silver stuff was used by the WinneBeast's PO and it had to be re-done every year.  After about the 3rd year, it would all need to be scraped off and done again.  In addtion, he used roofing pitch in caulking tubes (about a buck each) on the seams and around the roof fixtures and, not only does the pitch sink into the seam almost immediately, requiring multiple coats, mini-cracks appear within a year, the leak returns and it is the most gawd-awful stuff to try to remove!  It took me hours just to get it completely off from around the A/C where it appeared umpteen tubes were used in an attempt to stop the leak... an attempt which failed completely.  Bottom line on the silver coating and cheapo roof pitch - - Don't use it, it's a total waste of time and money.

[DanD2Soon]

Sent: 6/20/2004

If you're planning to use eternabond later, don't use anything now that has silicone in it - the ONLY thing eternabond WILL NOT stick to is silicone! Much of my roof has the aluminized fiber coating on it and if you're trying to seal a crack in it, the aluminized stuff behaves very much like you described for roof pitch.

Eternabond will even stick through water - About four years ago, we were parked about as perfectly level as we ever have been and got caught in a really bad all day rain storm, moving wasn't an option - the crack was about 6 inches long just inside the roof edge seam - the ridge from that seam was keeping the water from just draining off the roof. I took a 10" piece of eternabond tape up there, peeled off the release backing and stuck it down starting a little before one end of the crack and "squeegie'ing" it down as I went a little past the end of the crack. Then I used my thumb to push the eternabond down tightly on the crack and worked the pressure out from the center to the edges all around. It stuck, It stayed, It stopped the leak and it's still there! - amazing. Hey... Ya Know those guys should be paying me for this!

Anyway, later when I went to replace my eternabond tape roll, my local RV place didn't have any even though it was in their catalog and tried to sell me several of the products they had on the shelves. When I refused their pitch, (no pun intended) They ordered me a couple rolls and got some to try themselves - at both local RV shops, if you order by Sunday, they have it on Wednesday - Now they won't use anything else either and I think they still have a couple rolls of the stuff they tried to sell me on the shelf. Their Service manager told me last year that one roll of eternabond and lots of "Quick Fix" leak jobs have won them more repeat service customers at $65/Hr. than any promotion they've ever used!

I just looked in my 2003 RV Parts & Accessories catalog - the 600 page one that all the RV stores use and have their own name printed on the cover...looked in the advertiser's index at the back of the book & it has eternabond products listed on page 198 - $80.59 for a 4 inch by 37 ft. roll. (white)

One last story & I'm off my soapbox... My plastic blackwater tank had/still does have a split in the bottom about 14 inches long - I emptied the tank, let it dry, steel wooled the tank bottom about 4 inches all around the split, put one 2 ft. long piece of eternabond tape directly over it and then overlapped it from each side with 2 more strips, wedged a piece of 3/8" plywood about 6 inches wide by 3 ft. long between the tank support straps and the tank right over the split. It hasn't leaked since and I don't ever intend to replace that tank.

'Nuff for now,
DanD

[Photoman]

Sent: 6/20/2004

I discovered we had a leak in our '72 C20 Brave when we were camping about 2 weeks ago and got caught in a very heavy downpour with some quarter-size hail (cringe!). It was dripping from the ceiling strip over the overcab bunk (the strip furthest from the clearance lights, but still over the bunk.  Fortunately we had a plastic table cloth we laid over the bedding and sponged up the puddle of water before it could get the foam mattress wet.  When we got home, I inspected the roof and it looked to me like the most likely places the roof could be leaking would be the 2 front cross seams.  So I cleaned them off real good and laid down a 4" covering of Eternabond on those 2 seams the full width of the roof and over the edge of the aluminum gutter.  Then I did the same over the very back edge of the roof and the 2 seams in the back like the front seams as they looked in pretty bad shape.  I noticed as I walked on the roof that in most places the aluminum skin has separated from the underlayment.  Nothing I can do about that I guess without a major repair job.  Something I'm not qualified to do.  I thought everything was hunky dorey until we got another heavy rain...glad I left the tablecloth on the bed as it was dripping in the same place.  I'm at a loss as to where the leak is coming from.  I plan on covering all the seams with eternabond, and then laying down a strip the full length of the gutter on both sides.  What about the clearance lights? What's the best way to re-do the seals on them?  We had  an air conditioner installed at a RV dealer about 8 years ago as our bago didn't come with one from the factory.  I don't think it's the source of the leak as it's never leaked when we've had it running, and the ceiling around it on the inside seems fine.  The paint is oxidized and completely off on some parts of the roof, so after I get the Eternabond down I plan on putting on a coat of Tractor & Implement Gloss Enamel paint I got at the local Tractor Supply Co. Does anyone know if anything has to be done to the bare aluminum before using this paint?  I think maybe lightly sanding might be in order.  How about the Eternabond tape?  Do I just paint right over it?  Thanks for any ideas.  Photoman

[Oz]

Sent: 6/20/2004

I had this very same problem.  The clearance markers were definitely the culprit.  You can take a square of the tape, sized to fit under the light (not meeting the outer edge).  Cut a slit in one side and make a hole in the middle large enough to clear the wire and the mounting screw (you don't want anything on the screw if it is used to ground the light).  Place the square around the wire and screw, press the slit together to complete the seal, and re-mount the lense.  This will press down on the tape and seal the wire hole and screw from water. 

Remember that water will certainly travel across separated roofing so, it still may be that the leak is actually somewhere else so, you are wise to cover everything.

As for the roof paint... you really don't need it and you should never paint over Eternabond or any roof sealant.  The paint will only harden on the pliable sealant surface and crack along the edges.  Eternabond will stick to everything except silicone, including bare aluminum.  What you can do is, seal everything with the tape, and then coat the roof with Kool-Seal.  I think it is best, while you're at it, to remove the vent(s), any railing, ladder, telephone poles, circus tents,.... whatever you have up there, and lay tape under them and then screw them back in.  This will give you an excellent gasket effect rather than just covering the edges of the accessories.  Use the tape over the seams, as you said and coat the whole thing.  Bake at 325 degrees until the fish is opaque white and flakes easily with a fork...  AAARRRG!  Don't you just hate having to communicate with a lunatic?

[Photoman]

Sent: 6/21/2004

Sob...Thanks for all the helpful info.  I'm betting my leak is coming from the clearance lights as they don't look like they have a very good seal on them.  I did a google search on Eternabond and was surprised to see there are several different types of the stuff.  They make a double stick Eternabond tape that is 2" wide, 60mills thick, and 50' long that works as a gasket for windows & vents (and I'll bet would be great for clearance lights). I found the best prices from socalroofingsupply on the web.  The double stick is $35.95 and the white Eternabond 4" by 50' tape is $45.95 + $5.00 shipping. I've seen other places on the internet selling the same tape for $79.95.  I also saw that the Eternabond material is available in square sheets big enuf to make gaskets for vents and air conditioners. 
    I'm not familiar with Kool-Seal. Is it like a paint?  I was going to use the TSC Tractor & Implement paint because I need to paint the whole Winnie as the paint has oxidized badly and has flaked off on the sides.  But maybe I should re-think and go with the Kool-Seal?  Is it just for the roof?
    I don't have to remove the telephone poles or circus tents as I took care of them when I went thru a low clearance tunnel on the last trip.  Photoman

[Wendell]

Sent: 4/23/2007

Had an unfortunate experience last trip.  We got a pretty good shower the first night and water began to drip through my roof A/C unit.  Like most of our rigs, I have a little sag in the roof and the water ponds around the A/C.  However, when I pulled the inside cover off the air conditioner, I discovered that the rubber seal was protruding into the hole in one corner and wasn't holding the water out there.  It was seeping past the gasket.  It wasn't pouring through there, but just seeping drip by drip.  I was able to put a catch pan under it to keep it from wetting down the whole RV, but it was a pain. 

Anyone ever tried replacing the gasket on one of these bad boys?  What kind of tips can you give me?

Also, I purchased a small battery powered submersible pump at Lowe's and this pumped the water off the roof in no time.  Going to keep that puppy in the RV from now on.  Great for pumping clear water out of just about anything.

[mnboy26]

Sent: 4/23/2007

The roof seal is a fairly easy fix, i had the same sag too and after awhile the new seal I installed a year or so back started the same drip....so I put a bead of silacone on the bottom side of the gasket and that solved the problem...you might want to think about doing the same thing....we had a huge downpour here last night i checked it and no drips anymore, hope this helps

Craig
1972 D-20 brave
1996 Airstream Cutter

[tatkin]

Sent: 4/25/2007

After taking the old one off and the new one on I almost think that if I had to fix it I would take thick styro and cut a square without openings around the corners and put that up there.

The weight of the AC unit I think would compress it.   

The stuff , the square that came with the new AC unit is ? thick foam ...  Without openings on the corners or anywhere around the outside of it.

Plus a bunch of roof goop ...

[ClydesdaleKevin]

Sent: 5/11/2007

If the seal is bad, replace the whole thing!  Yeah, I know they are like 40 bucks, but its worth it!  If the corner wasn't messed up, I'd suggest snugging the AC hold-down bolts a little, but with the corner messed up, replace it.  Don't use silicone or anything else...replace the darn thing.

Replacing it is easy.  Just remove the inside AC ceiling unit, and then remove the hold down nuts...should be 4...some units may have a different number.  Now, get on the roof and CAREFULLY lift the AC unit off the opening.  If its sticking, use a putty knife to get between the aluminum and the unit...old aluminum can peel back like a sardine can!  Using a razor window scraper, remove the old seal from your roof AND the AC unit.  Now install the new seal squarely, covering neatly the whole 14" opening.  Get a buddy to help you and lower the AC unit over the seal.  Once that is done, get back inside and snug down the hold down nuts...not too tight!...too tight and you'll damage it and have a leak.  Err on the side of caution, and leave it too loose if you are not sure...you can always snug it down tighter later if you have a leak.

Good luck!

Kev and Patti