Common roofing mistakes happen daily and frequently don’t become evident until they cause a significant problem.
Unfortunately, it’s not uncommon for a roofing contractor to ruin a project and cause frustration for homeowners and building managers.
Failed inspections, voided warranties, and problems with your insurance company are just a few things that can result from a roofing mistake.
As a consumer, you must know the tell-tale signs of a substandard or inexperienced contractor.
That’s why, in the following post, Roofer’s Guild highlights some of the most common mistakes that substandard (or possibly inexperienced) roofing contractors make.
1) Using Roofing Nails that are Too Short
Almost every type of shingle has an ideal length of roofing nail. These standards are in place to ensure that the nail goes through to the decking.
However, there are a lot of nail lengths to keep track of, and if you’re not diligent, you can easily end up using the wrong nail length. And one of the biggest problems is that the issue isn’t always evident to the roofer.
You may think that the nail has a good hold in the decking, but it could barely be penetrating the surface.
It will only be after the contractor leaves and some wind starts to blow that the shingle will begin to shift. Once you have shingles that are shifting on the roof, it can seriously compromise the lifespan.
Remember that roofing nails need to secure the shingles into the decking, so they require proper nails for the type of shingles installed.
2) Not Accounting for Slope
Different roofing materials are required depending on the roof’s slope. For instance, something like built-up roofing will never be appropriate on a pitched roof.
However, many novice roofing contractors simply want to offer their customers a wide array of roofing material options.
This can be a pitfall even if it is born of good intentions. First, the slope has to be carefully measured to ensure proper roofing materials are used.
Too often, substandard roofing contractors will fail to accurately account for slope and use the wrong types of roofing materials.
3) Recycling Flashing
By far, one of the most common roofing mistakes is simply cutting corners. In roofing, cutting corners often takes the form of reusing old flashing. Flashing is made of thin metal sheets. Its job is to waterproof the breaks in your roof line.
For instance, where your chimney meets the shingles of your roof, flashing is installed to protect the seam created from water penetration.
During a re-roofing or shingle replacement job, it may seem that the existing flashing is in good shape. So some roofers may simply reinstall the old flashing once the job is done.
However, the flashing should be replaced with every re-shingling or re-roofing job. It also needs to be replaced if it has been compromised in any way.
4) Exposed Roofing Nails
The roofing nails need to be driven into specific locations in a shingle roofing system. Typically, the nail should be placed under a layer of shingles to protect it from the elements.
However, one of the most common roofing mistakes is putting the nail in the incorrect position.
When the nail is driven into a spot where it is exposed to the elements, it can cause it to corrode.
When the nail begins to rust, it can either cause a hole in the shingle or compromise the integrity of the nail – or both. In any case, it will leave your roof more vulnerable to leaks.
5) Not Installing A Drip Edge
A drip edge is a metal flashing that should be installed under the leading row of your shingles. The purpose of a drip edge is to channel water that has drained off your roof into your gutters and away from the exterior walls of your building.
While modern building codes require a drip edge, some older homes don’t actually have them.
When completing a roofing project, some roofers may assume that since your home is older and has no drip edge, it doesn’t need one. Unfortunately, this is a common roofing mistake.
It can even happen because the roofer doesn’t want to spend the time or the money installing a drip edge on a new roof.
But the results of doing so can be catastrophic. Drip edges also prevent water from getting under the leading row of shingles.
When water is allowed to get under the leading row, the entire roof can be compromised. Not installing a drip edge can cost thousands of dollars in damage.
6) Omitting Underlayment
Many people don’t realize that even residential roofing systems are made up of multiple layers. First, there is the decking, which is basically the foundation of the roof onto which all materials are secured.
Then there is the upper layer, which comprises your shingles, tiles, standing seam metal, or slate.
But between the undermost and uppermost layers is something called underlayment. The underlayment of a roofing system helps add a layer of water protection.
Underlayment is basically a sheet that is made of paper or an organic mat that has been treated with asphalt.
It goes on top of the decking and underneath your roofing materials to prevent leaks in the most vulnerable roof areas, such as the valleys.
Unfortunately, once again, you will get some substandard contractors who will omit the underlayment to cut some corners and save some money.
7) Disregarding Manufacturer Instructions
Most roofing materials come with instructions for the installer to follow. But one problem that many seasoned contractors have is thinking they know these instructions by heart and not reviewing them.
And while the installation may still be done to professional standards, it might not have been done to the manufacturer’s standards. This can be problematic because it may void the manufacturer’s warranty.
This is the best-case scenario. The worst-case scenario for disregarding manufacturer instructions is that the materials are not installed properly at all, which could lead to more expensive roofing issues down the line.
8) Sagging Roof Gutters
Gutters need support to withstand water weight. Improper placement of screws can lead to gutter sagging. Other problems occur when gutters are too narrow.
For example, some homes have 4-inch gutters that cannot account for climates with consistent and severe rainstorms. Eventually, the water backs up and causes the gutters to sag.
9) Failure to Install Starter Shingles/Strips
Contractors should always lay down started shingles along the eaves and rake edges for sealing purposes.
Failure to install starter strips almost always causes water damage as the liquid can more easily penetrate the roof decking.
The use of starter shingles is typically within the contract, so make sure it gets done.
10) Not Having Roof Contractor Insurance
Contractors without proper insurance may not be responsible for injury or roof damage, which can pass the buck your way.
Any reputable roofer will present proof of insurance before working on your roof. However, some sketchy contractors will attempt to avoid the conversation and lull you into a false sense of security.
Contact the insurance company to verify their policy if you suspect something amiss.
11) Mismatched Shingles
Roofers that install mismatched shingles will make their mistakes evident for everyone to see. This problem typically happens when the contractor buys materials from multiple suppliers for a single job.
Unfortunately, mismatched shingles can ruin curb appeal and suppress home value.
12) Poorly Installed or Secured Valley Flashing
Valley flashing is prone to water leaks because they typically withstand lots of rainwater. When your contractor ruins the installation or fails to secure the valley flashing, the entire roof can buckle and cause damage.
Failure to utilize sealant and adhesive material can also cause water infiltration.
13) Incorrect Shingle Overhang
The correct measurement for shingle overhang (at the eaves) is 7-10mm. Any size over 11mm may result in severe roof wind damage during inclement weather.
On the flip side, anything under 6mm invites water penetration of the roof deck, which ultimately causes severe leaks.
14) Incorrect Shingle Exposure
Shortened shingle exposure causes moisture build-up and may result in blow-offs during severe windstorms. In contrast, too much length between shingles puts your entire roofing structure at risk of water damage.
15) Misaligned Shingles
Misaligned shingles are one of the easiest roofing mistakes to identify for non-professionals. With a simple once-over, you can notice when shingles are not on the same horizontal plane.
Of course, misalignment makes your roof look unprofessional, but it can also create vulnerabilities and lead to water damage.
16) Failure to Address Ice Dams
When melted snow freezes at low temperatures, ice dams can quickly form beneath roof shingles. As the weight increases, your eaves start to suffer.
A proper installation ultimately accounts for future ice dams by including a barrier covering your roof’s edge.
Some cities require this based on building codes. However, some roofers simply neglect this step.
17) Neglecting a Roof Permit
If your hot-shot roofing contractor fails to secure a permit, it can spell disaster for everyone involved. Most areas mandate roof installation permits; however, some contractors ignore the requirements.
If the roofer gets busted for working without a permit, the entire roofing job may get suspended.
The easiest way to avoid this is to use a licensed and bonded contractor with many favorable reviews.
18) Improper Attic Ventilation
Attics are part of the roofing system, whether you realize it or not. However, if your contractor does not realize it, you can be in for a never-ending nightmare.
In addition, inadequate attic ventilation can damage your roof during heat waves.
Ultimately, this leads to increased energy costs and roof decking failure. As a result, your roofing contractor should ensure your attic is equipped to support your roofing structure.
19) Mixed Slate Colors
Slate roofs require uniform colors to maximize curb appeal. Unfortunately, contractors’ use of multiple suppliers may result in a porous-looking slate roof.
In rare cases, mismatched colors can come from the same supplier and even the same batch.
Still, a reputable contractor won’t install anything until it’s perfect.
20) Failure to Remove Old Shingles
When asking the question, can you install new shingles over existing ones? The answer should be no. Any reputable roofer will remove the old shingles before installing the new ones.
Making the mistake of installing new shingles over old ones results in punctures that invite moisture.
Ultimately, making this error results in roof deterioration and the massive repair expenses that manifest as a result.
