Over the years, we’ve seen people make all kinds of mistakes when installing a metal roof. In this post, we cover the five most common mistakes you should look for when installing a new metal roof.
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Incorrect panel lapping
Many roofers tend to lap the panels the wrong way. The fat lip goes down first. The short lip has this little leg attached to the joint. Cover the panels in a way so that the short lip shows on the top.
Screws fastened incorrectly
Make sure that each of the screws is properly fastened. Don’t over tighten or under tighten the screws. Keep the washer a bit loose. Place the screws in the flat spot in the middle of the panel. If the screws are not properly set and you’re getting a lot of wobbling, you may need to change your nut driver.
Don’t rely too much on sealants. Some roofers think they can fix a roofing mistake or work their way around a difficult patch of the roof simply by applying a thicker layer of caulk after they’re done. Sealants and caulks are a secondary means of waterproofing.
Keep in mind that the caulk should be applied underneath your trim or panel where it’s safe from weather and sunlight. It’ll last longer in that position than if you lay it out in the open.
Extending the panel too long over the edge
Some roofers make the mistake of letting the metal panels extend too much or too little over the roof’s edge. Let the panel overhang by about an inch and a half to 2 inches. This applies to the gable edge and the bottom end of the roof.
Pipe flashing covered by too few screws
The area on a roof most prone to leaks is around a penetration like a PVC pipe. Flash these kinds of penetrations with great care and attention. Some roofers secure such areas using a few screws and then splatter a layer of caulk over it to keep the water out.
This is not the best process to follow. When the caulk wears out, you will have a leak there.
When installing the boots, put sealant underneath the base of the boot so it’s hidden from sunlight. Secure the base against the metal by placing sufficient screws all around the perimeter of the base.