Either way it has to be/should be done indoors where it is warm. Either way better to have it done by a pro if you can afford it. The roof must be dry before starting and no rain the whole time(several days)
Choose the right stuff!! You can get some that just peels off like a skin later on. I got the Liquid Rubber stuff from Amazon.ca based on a friend tried it on his RV and it worked well (after a struggle he had --see below--so I knew what I was getting into)
If you are "on a budget" you can do the coating job yourself but a real replacement job with new rubber, probably not.
Long story here to make you think twice about doing it yourself:
I did mine this summer with a lucky long stretch of sunny days and little wind. Pine needles get stuck in the wet coatings. It takes a day to dry before the next coat. It is still sticky after it is dry enough for the next coat, but you can't wait for it not to be sticky-- that takes a couple weeks and you need to do the next coat next day before it "cures".
I found you need to wear just your socks or bare feet so your shoes don't lift what is down so far. (You can do the prep coat half at a time and cover that half with the real stuff to dry so you can then be on the first coat to to the prep stuff and first coat on the other half--after that, you do the next coats however for being on yesterday's coat)
It took me five coats to use up the five "gallon" bucket enough to meet the instructions for amount per square foot to be thick enough. Learned to slop it on with the roller and not roll it thin or it just means more coats and so more nice days needed at one coat a day. The weatherman is not your friend. That is why they do it under cover (also fewer pine needles indoors!)
You need first to be sure what the roof material is, since they have different coatings and prep coatings depending on which type of "rubber" roof you have. There are youtubes on that- where to find a bit of loose roofing to see if the backing is black or white (inside the rv in a vent where they tucked some roof down inside, eg)
I was lucky when I learned my horrible 1991 roof turned out to be the wrong kind of rubber just before I used the prep stuff. They don't have any prep stuff for the other kind of "rubber") so I just used the actual coating stuff, and it did stick even though their tech support guy thought it would not for sure, and even to Eternabond--which apparently has different types of white stuff on top too which not all types will let the coating stick-it stuck to mine ok where I have lots of bandage patches. Anyway, it all took a week, and was something of a nightmare, but it got done. :)
Couple months later now and it is nice and hard with no lifting anywhere and is still a tiny bit sticky but gradually getting less so. It washes up nicely and no more roof troubles like before where it was turning into a giant mess of Eternabond patches. (Kneeling to work on a vent, eg, my toes would make a gouge in the old roofing to bare wood) Just awful. Now all fixed.
I could not have done it without that long stretch of nice weather--you don't get over a week with no rain at all often around here. Watch out for cool nights and condensation--wait till that dries off in the sun by lunch and do the new coat then so it is nearly dry before dark and cool again. In Saskabush you will not have pine needles, but probably get grass-hoppers instead. :)
I'm sure others who have done this job will say it is not nearly that difficult, but that's how it went and also pretty much what my friend went through with his. We are both happy with our new roofs, but it was quite a chore.
https://liquidrubber.ca/products/rv-roof-coating?variant=4274310340&gclid=EAIaIQobChMIsIjJ7IiH8wIV-gutBh2YjwRPEAAYASAAEgLmJPD_BwE
