Arizona Ranch Home with Air Conditioner Mounted on the Roof


Dear Experts,

 My son is a roofer in the Northeast and we just retired to Phoenix Arizona where we need a need a new roof.  The problem is that the central air conditioner unit is mounted on the roof and my son from the North East has never dealt with this before.

 Can you give me specific directions and protocols on how to replace the entire roof while also dealing with this central air conditioner unit mounted on the roof ?  I am sure that if an expert professional who does this routinely can pass on how to deal with this my son can manage this safely and effectively. He thought he could just lift the unit and carry it to the ground via the ladder and I am afraid he'll get hurt trying to do that !

 Please help with your advice.  I thank you, Steve


Keep in mind that roofs don’t leak, holes in the roof leak. The AC is a prime suspect for a leak in the future.

Keep in mind that roofing is often regional. A white EPDM roof is great in Florida, but not my choice for Alaska. It is important to check with a LOCAL roofer with years of experience in your area dealing with that issue.

If it was my roof, (site unseen) I would remove the air conditioner, re roof, flash where necessary reinstall air conditioner and seal around every penetration made by the AC.

You can use Chemcurbs or E-curbs for that


Flat roof? Shingle roof? Either way, why not just work around it and flash everything properly?


Absolutely a possibility. Without seeing it I am guessing it is a small easily removed unit. 6 of one, half dozen of the other IF you have a quality roofer who does good work.

I have seen issues in the past where the AC goes out and the heating & cooling people have a harder time repairing it, but that was not a quality job.


This is probable a similar setup as the nursing homes use in this region. It’s most likely a solid curb with the duct work in side of it. There is also the possibility that it is just the condensor on the roof and the evaporator is in the attic(not an ac guy so don’t know the correct terms for the two seperate units) connected buy two copper lines. Either one can be flashed properly and correctly without removing the units.
Stevekevin if you can give us a better description or pics we can try to help you but it would be better if you contacted a roofer in your area.
Also if the roofer mentions using ice and water shield to flash it in ask them if they can at least use epdm. Those units hold alot of water on the upper side of them and i don;t trust only ice and water shield



I was in Phoenix in February and in Vegas a couple of years ago.Both were for soccer tournaments but the roofer in me had me looking at the roofs half the time. What I noticed was the a/c units on the roofs. On almost all of them the unit was on a section that had epdm on it. It looked to be a 1 1/2 to 2 square area.
As long as your son can do rubber and shingles and knows how to tie the two together then he should not have a problem.

I am assuming that your roof is this way.Having not seen it I can only guess.




You can use Chemcurbs or E-curbs for that[/quote]

Excellent, it is also helpful for me… Thank’s a lot




You can use Chemcurbs or E-curbs for that[/quote]

Excellent, it is also helpful for me… Thank’s a lot[/quote]

Liquidrubber is a poster from China; his posts are only just starting to make sense.