Upon being asked to relay my thoughts on whether investing in a steel roof is a good thing, I decided to secure an opinion straight from the horse’s mouth, well, actually, Jim Hoarce’s mouth, one of our longtime local professional steel roofers.
“So Jim” I inquired, “after installing steel roofs for the last 30 years, would you recommend steel roofing to the average homeowner?” To which Jim answered, “If the customer is prepared to pay for the proper underlay materials, follow the recommended installation procedures, and use only approved flashings, gaskets, and snow stop brackets, then steel can make for an excellent roof”.
OK, sounds pretty simple, all a homeowner has to do is ensure his roofer follows the installation instructions.
Unfortunately, its human nature not to follow instructions. We purchased a high chair for my grandson recently, and it was my goal to not have to read the instructions, after all, I was looking at maybe 20 parts.
Now, I understand there’s a reason why my chosen profession is in retail, and not engineering, but 20 parts?
Regardless, after 2-3 minutes of assembly frustration, I searched and found the instruction sheets at the bottom of the box. Thankfully, they came with pictured diagrams, which were essential in successfully assembling this unit in under 15 minutes.
Conversely, when an amateur, or your cousin’s buddy, is on your roof, and there’s a cool wind, and it’s getting late, or almost time for a Tim’s run, what are the chances this fellow’s going to take the time to read the instructions should he be faced with an installation dilemma?
Or, might he just plant a few more screws around the issue, and be done with it? According to Jim, the number of calls he receives each year from homeowners asking him to come over and repair, or find the leak, on a roof that was installed by somebody else, indicates how often steel roofs are not installed as per instruction.
A steel roof is great, until it leaks.
Therefore, choose only an accredited steel roofing professional. Next, start with a 5/8” plywood sheeting underlay. Because steel roof sheeting is screwed in position, Jim strongly suggests the heavier 5/8” plywood, as opposed to ½” sheeting, commonly used for asphalt shingles.
A 5/8” plywood offers superior rigidity, and better accepts a screw. Should steel roofing be installed over existing asphalt shingles, thereby saving the dumping fees? Or, can steel be installed over a boarded roof that’s been stripped of its shingles? What about strapping an existing asphalt roof with 1×4 spruce?
No, no, and no.
People regard steel roofing as being relatively lightweight, which it is if you’re handling one 10 ft. sheet at a time. However, stack ten of these sheets together, and steel gets heavy real fast.
So, steel is relatively lightweight when compared to asphalt, but it’s not that light, and if layered upon existing roofing, will provide an unnecessary burden on your trusses.
Plus, an asphalt shingle base is too spongy, which may cause the steel screws to loosen over time. When screws loosen, water gets in.
Boarded roofs and 1×4 strapping underlays are strategies of the past. Why? Because they lack the stability of plywood, with these planks shrinking and warping over time, loosening the screws.
On top of the 5/8” plywood Jim recommends either a UDL50 Titanium underlay, or Lastobond, high heat rubber membrane (similar to an ice and water shield), offering an essential second line of defense.
Next, Jim’s two final recommendations are simple.
One, buy heavy. Heavier gages of steel lay straighter, dent less easily, and just look better.
Two, decapitation is real. Not that the heads of unsuspecting homeowners are found in our snowbanks every February, but snow and ice sliding down a steel roof can be a very destructive weapon. So, invest in heavy duty snow stop brackets. The little polar blocks will do little to stop a weighted avalanche of snow and ice.
Thanks Jim. Good building.