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Watch Out for the 10 Most Common Roofing Mistakes

bad roof flashing

When it comes to roof replacements we’ve seen it all. From bad to worse installations, we have been called to come and fix what another company or homeowner has done incorrectly. From all of our experiences, we have noticed some trends and want to share some of these with you so you can avoid them and save yourself a major headache.

  1. Starter shingles missing or installed incorrectly. This is a common do-it-yourselfer mistake. It’s very important to lay down a starter section of shingles near the eaves. If you miss this step, water will inevitably enter the sheathing beneath the shingles’ cutouts. This leads to leaks, ice dams, ruined shingles and much more damage down the road.
  2. Incorrect nailing. Shingles slip and shift around if they are not nailed in the exact right location, or if too few nails have been used. This can be due to a laborer rushing or being too sloppy with their work. Most shingles require at least 4 nails per shingle if it’s not a steep grade. Nails should be put through the nailing strip and not come into contact with the self-sealing portion of the shingle. This can lead to leaks and roof failure if done improperly. It’s also difficult to trace because nail placement affects every shingle on your roof and water can travel a long ways before being detected inside your house.

    Low nail,high nail
    Examples of the common roofing mistakes low nail and high nail.
  3. Improper ventilation. Ventilation is important for roofs because it can affect moisture buildup and cause an entire roof to fail prematurely if done incorrectly. This includes an overall attic plan to ensure the ventilation needs are met, which may include adding a new ridge vent, eave venting, baffles to avoid blocking attic airflow and addressing any other areas where “short-circuiting” may be occurring. Short-circuiting occurs when there is an improper gable or box vent that is allowing airflow to travel a shorter distance, which leads to ineffective attic ventilation. This is easy to mess up and is very common among low-cost, low-quality roofing companies.
  4. Wrong slope. Selecting the right material for the slope of the roof is essential to a quality roof installation. The wrong selection leaves the roof open to water penetration. If installing an asphalt roof, the minimum slope is 4 units of rise per 12 units of run. Asphalt shingles cannot safely tolerate a lesser slope than that.
  5. Incorrect shingle alignment. This is one of the easiest tell-tale signs of shoddy roof workmanship. When the cutout on a three-tab shingle are not placed vertically or the butted joints are not on the same horizontal plane, the shingles are not aligned properly. This leads to accelerated shingle wearing, more prevalent leaking and eventually premature roof failure. And it’s easy to spot!
  6. No plan for ice dams. Here in Michigan, ice damming is common. They occur when snow melts on the roof and then refreezes, which can force water underneath the shingle where it can pull shingles up and add unnecessary weight to your eaves and gutter system. We prevent ice damming by putting our Pro Ice and Water Shield down along the end of the roof to prevent water from infiltrating in that ice-dam prone area. Missing this step can save a company money, but will cost you money down the road.
  7. Incorrect securing of valley flashing. Roof valleys are highly prone to leaks because they handle so much runoff water. Not securing the flashing properly using sealant and securing materials can lead to buckling and failure of the flashing. It’s easy to miss and do incorrectly, unless you have highly-trained installers.

    Common mistakes in roofing
    Don’t let poorly installed flashing shorten the lifespan of your new roof.
  8. Incorrect installation of valley flashing. The other aspect of valley flashing that is so important is the valley flashing installation. Flashing needs to be layered underneath shingles properly, never laid on top of shingles. The U-shape of the metal on the flashing should face the valley. Without the correct installation, water will quickly find the point of weakness and speed the deterioration of your flashing, shingles and roof.
  9. Wrong shingle exposure. For a typical three-tab shingle, exposure of five inches is commonly suggested. If this is shortened at all, this leaves the roof open to collecting moisture during a storm, instead of shedding it. It will also be susceptible to being blown off if there is every a high speed wind storm.
  10. Wrong shingle overhang. The end of a shingle should hang over a roof between 1 to 1.5 inches, or between 0.5 and 0.75 inches if the drip edge flashing is installed. Too little overhang allows water to run into fascia boards. Too much overhang and the shingles are susceptible to blow off during high winds. Since this is a game of inches, it is important to be precise and not leave this type of thing to chance.

Roofing can seem like a laborious job where the task is simple, remove old shingles and install new. But without considering the finer points required by the type of roof, the attic, the slope, the climate and the material to be used, it can be easy to mess up the details leading to a massive out-of-pocket cost in the future. This is why relying on low-quality roofing companies without a great track record can be cheaper in the immediate term, but they will likely miss the details and leave you with an unsatisfactory result. If you would like help getting your roof replaced by proven professionals, call us at 888-776-1998 or request a FREE estimate here.