I’ve got a near flat metal roof with closed cell insulation on the inside that’s starting to leak around some screws and was wondering if someone has experience with putting a sealant on the outside of of the building, also the product used? I’m looking for a few years until I can build a new building

Butyl.

Is that sprayed on or rolled?

Caulk tubes

Have rolled white paint/sealant on roofs to do what you need. It works.

Flex Seal worked on several of my blinds.

Tubes would take awhile on a 50x100 foot building. Turkeytime do you remember the name so I can look at the product.

Lefty this one is pretty flat it was built in 1973 or 74 it’s one of those steel structure sheds that have sloped sides, a low sloped roof that flexes in the wind, you’ve probably seen them, it just started leaking, we’re pretty sure the steel structure is getting bad and why I only need a couple of years to get something built over the top of it.

Here’s a reference picture.

I like the aluminum fiber roof sealant like is used on mobile homes for a flat roof sealant....Apply with a cut down broom.

As we all know, metal expands and contracts during hot and cold temperatures. Most metal buildings, (I have assembled a few, and installed many metal roofs), the fasteners are the culprit when leaks start to appear in random, isolated areas. Also, most fasteners for metal structures have a neoprene "washer" that deteriorates over time. Metal expands and contracts and causes the holes around the fasteners to wobble out, letting water in.
If you have exposed fasteners, (screws or bolts), I would check them and replace as needed. I have replaced entire roofs that were 20 years old. The metal panels were good, but the screws were rusting and the neoprene washers were flat and hard.
Condensation is the number two cause of leaky metal roofs. If there is a way for conditioned air to contact a cold roof, without proper ventilation and a vapor barrier, condensation will occur.

If you’re gonna do anything, replace the screws and seam tape.

Exactly right Lefty. Most steel panel roof manufactures recommend a 4/12 or steeper. Anything less voids any warranty that might apply.

X 2

They make a metal roof screw that a I use for replacing old screws
It's a little bigger in diameter and has aggressive threads
Look up liquid rubber products, it's expensive but it will work just fine after you replace the screws and give the roof a good cleaning

Do some research on types of joint sealants used on rv's they are fantastic!
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On many different campers I've successfully used a product called Through the roof ! I've seen it in small containers up to 5 gallon buckets .

The best part about it is that even of it's wet / raining it will still seal off the leak ! The down side is it's a bit pricey but how well it works it pays for itself .

A friend of mine rolled it onto numerous roofs on his property many year's ago and it is still holding up like a champion it really is , the same goes for the camper roofs no leaks !

Prep and wash will be the most important part. We spray all kinds of shop/ag buildings like that. You’ll want to get a hybrid urethane sealant/caulk in tube or buckets and do all the seams and fasteners. That could get you by but a full restoration. I’d then put a top coat over it 18-20mills thick across the whole roof deck.


Whatever you do don’t put the silver or aluminum crap on there.