You’ve recently had a roof replacement. However, after your roofer left, the roof looked unequal for two weeks. It’s normal for roofs to look wavy and rippled for at least a few days after installation because the material is still settling in. However, if your roof still looks wavy and rippled after a long period, it’s a sign your roof might have had a problematic roofing installation.

Here are three causes of wavy and rippled asphalt shingle roofs.

Granule Loss

Asphalt shingles have protective granules that allow them to reflect UV rays and reduce heat absorption that causes them to turn brittle and age quickly. Unfortunately, they lose these granules over time due to tornadoes, hurricanes, and other destructive natural forces. Granule loss can shorten your roof’s lifespan and introduce blisters that can cause it to appear wavy and rippled.

Sheathing Issues

Roof sheathing is made from OSB or hard timber that isn’t susceptible to drastic thermal expansion during summer and winter. However, older sheathing on your roofs can cause waves and ripples after roof replacements. You may notice sheathing issue symptoms before removing aged roofing materials. Water damage and wood rot are the primary causes of most sheathing issues on roofs.

Overlaying New Asphalt Shingles

Roofing contractors will never recommend overlaying new asphalt shingles on aged materials because it can cause significant structural inconsistencies and go over your existing roof’s load-bearing capability.

APCO has a great explanation on why your roofs are wavy or rippled. Read more about it in this excerpt.


A wavy roof is rather alarming, and unfortunately there are actually quite a few potential causes. However that pronounced wave will nearly always signify one big thing: your roof is buckling or bulging somewhere, or the materials simply aren’t lying flat. Let’s go into some more detail to give you a better idea.

Is Your Roof New?

This is an important question to ask in this situation because the most common causes tend to come about at this time. Thankfully this is also the easiest set of issues to remedy. If you’ve recently gotten a new roof and it got all wavy on you then here are the possibilities:

The shingles were laid over an old layer of roofing. This is a very unfortunate issue for everyone involved. What happens here is that a contractor laid out your new shingles directly on top of your old ones, creating an unnatural waviness that just isn’t going to go away. The roof will need to be stripped and reinstalled, and you should absolutely be grumpy about the whole thing.

The felt paper was a mess. A layer of felt paper goes down before the shingle does for every installation, which essentially acts as a base. If the material was damp, if the day was humid, or if the paper bubbled up a bit then it can produce a wavy appearance on your new roof. This is your number one best case scenario (and also the most common) because the paper should flatten out completely within a few weeks. It’s unfortunate for now, but it’s not permanent and it doesn’t need any additional attention.

New shingles are not aligned accurately. Sometimes you just get a bad apple. Roofing isn’t complex, really, but it is exceptionally precise. A bad measurement, improperly sized shingle, or low quality roof can simply result in an uneven and wavy appearance, which essentially means you got a raw deal. This is why working with trusted professionals is so important, and why the lowest quote doesn’t always mean the best!

Damage That Leads to Wavy Roofing

Had your roof for a while? In this case the waviness can only really be caused by a couple of things, most of which are unfortunate news, sadly. The most likely culprit is that your roof decking has been damaged. As to the extent of it, you’ll need a professional to come take a look, but don’t get your hopes up! Any amount of decking damage can result in a pronounced wave, so the problem could be tiny, but in most cases bad or rotted decking is going to mean extensive roof service and potentially roof replacement. (Continue reading here to learn more)

Cub Roofing is London, ON’s best roofing company with decades of experience taking care of your local resdential properties. Contact us today so we can help you with your roofing problems as soon as possible.