Quick Answer: Installing a silicone roof coating system is the best way to restore a metal roof. If the roof isn’t eligible to be coated, a spray foam roof is your next best option.
So, you have a metal roof, perhaps it’s leaking, and you’re trying to figure out the best way to stop the leaking.
Maybe you’ve done a repair before, but now another roof area is leaking.
Isn’t there a way to stop all these issues and get the entire roof under a new warranty?
In this article, you’ll learn:
- Why is installing a roof coating system the best way to restore a metal roof?
- What determines if a metal roof is eligible to be coated?
- What options do you have if your metal roof isn’t eligible for a coating system?
And just so you’re aware, West Roofing Systems has been in commercial roofing since 1979. We’ve seen hundreds of metal roofs, all with different problems and solutions to get them watertight.
Let’s get started!
Why is a roof coating system the best way to restore a metal roof?
Hands down, it’s the most cost-effective way to get a leak-free warranty. A roof coating system costs roughly $4 – $8 per square foot. Removing and replacing a metal roof will cost at least $15 per square foot.
There are tons of variables that sway the cost towards $4 or $8, such as:
- How long of a warranty you’d like? A 20-year warranty uses 50% more coating (30 mils) than a 10-year warranty (20 mils); thus, the cost is much higher if you choose the more extended warranty.
- No roofing system should be installed over deteriorated decking; thus, all the deteriorated metal must be removed and replaced before a coating system is installed. More replacement equals more labor hours added to the project. Plus, new material and landfill costs.
- The distance from the roofing contractor. Gas, labor hours, and hotel stays can increase the cost of a project. Don’t ever substitute quality for a contractor that’s closer. You’ll be very upset that you saved a few thousand dollars today because the quality of the installation was sub-par, and now you have leaks again.
A roof coating is cost-effective because it’s easy to install. A contractor sprays or rolls specific coating onto your roof.
Here is a before and after of a metal roof that’s been restored with a silicone roof coating system:
Roof coatings are great, but there’s one issue with them…eligibility.
Are all metal roofs eligible for a roof coating system?
There are three parameters:
- The seams on the metal roof must be in pretty good shape, such as still having a strong adhesion between panels.
- The roof has to have had annual maintenance. A roof that’s been neglected for years is usually in bad shape
- Less than 25% of the total metal panels on the roof need to be in good shape.
If any of these aren’t met, the roof is ineligible for a roof coating system. You can install it, but no manufacturer or roofing contractor will give you a warranty.
What options do I have if I cannot add coating to my metal roof?
Installing a spray foam roofing system is an excellent option if you’re ineligible for a coating system.
Because you can install a spray foam roof without removing the metal panels. This will save you tremendous money versus ripping off every panel and replacing them.
Spray foam costs around $6 – $12 per square foot, which aligns with most traditional roofing systems.
What makes spray foam stand out are:
- Spray foam is a minimum of 1” thick. It will cover every microscopic water entry point the metal roof has. This includes seams, thousands of fasteners, all penetrations, etc.
- Spray foam has an R-value of 6.5 per inch of thickness, which is higher than any other type of insulation.
- Spray foam roofs are seamless. Seams are probably why your metal roof is leaking. Spray foam is fluid-applied, then it expands 30x its size within seconds. No fasteners, plates, or other adhesives are used on a spray foam roof.
If you have a commercial metal roof, the most un-cost-effective thing you can do is rip it all off. It’s expensive, and you’ll add unnecessary materials to landfills.
At a minimum, you should get a coating contractor and a spray foam roofing contractor on your roof to get their quotes.
Then you can compare costs, problems, maintenance, and R-value and devise a solution that works for you.
Here are some other resources you might find helpful:
- Video: Silicone roofing system installed from start to finish
- Case Study – MTD – Spray foam over a 384,000 sq. ft. metal roof
- Case Study – Colonnade Towers – Silicone coating over 160,000 sq. ft. steep slope metal roof