Shingles are manufactured flat.
Shingles are bundled flat.
Shingles are stored flat.
Shingles are purchased flat.
If after your new roof installation you see shingles that are not laying flat? That is the installers fault.
100% of the time, if you take a flat shingle, and lay it on a flat surface, it lays completely flat.
What causes shingles to not lay flat?
A huge, and that is phenomenally huge, reason for shingles not laying flat, is that roofers lay bundles of shingles bent over the ridge. Yes, bent over. You could magically suspend shingles in the middle of the air, and as long as they are flat, there isn’t a problem.
SIDE NOTE: Bending shingles over the ridge physically damages them, regardless of how they look after installed.
Think about this. It’s gonna be a hot day.
Shingles are delivered in the morning, lifted up to the house by a piece of equipment. Shingles are stored all over, but the most common is all along the ridge of the house.
Those shingles sit in the sun all day. Absorbing heat. The stacks of shingles continue to dwindle as they are used. 2PM it gets very cloudy, the shingles cool off. Still bent. Getting closer to the bottom of the stack, where the impact of the bend is the greatest. Sharp ridge against the bundles.
The crew is working into the evening. Still cloudy. Sun is close to the horizon. Could even be a bit cool. Those bent shingles are now formed into a bend. They aren’t going to lay flat. Does the shingle installer care? (hint: Probably not).
By the time the roof is completed, it is dark. But the crew “finishes”. Cleans up. Everyone leaves.
The next day, it is light out, and you notice the shingles that are sticking up.
What do you hear as a response? “Sometimes that happens, and they will settle down in the heat in a few days.”.
Well, you assume that the Roofing Company is the expert, so you pay – and hope the shingles settle down.
And to be honest, they usually do settle down in the heat after a few days. That is a few days of the tar adhesive not bonding with the shingle below – dust will adhere to the tar strip, lessening the quality of the bond. If there is any blowing rain before the bond is made, certainly a bit of opening for the water.
OTHER REASONS FOR LIFTED SHINGLES
There are additional reasons that shingles can be sticking up.
One frequent cause I have seen are OLD ROOFING NAILS not removed that are still sticking up, and new shingles put right on top. This is a particular egregious situation, meaning that there was failure in multiple steps on the project.
The attitude of the Roofing Company is frequently, “We fixed that, no big deal. Part of our warranty.” I assure you, however, it IS a big deal. It is a signal of low quality.
Another frequent reason for shingles not laying quite flat, is problems along the eave where existing Ice & Water was installed. Removing the old shingles that are bonded to old Ice and Water is very, very tedious. Frequently, bits of shingle are left, and this creates little bumps that push up against the new shingles. Ideally, if the old shingles cannot be removed, the Sheathing / Decking along the Eave should be replaced.
Yes, it is expensive. Yes, this might cost you hundreds to thousands more to replace that sheating. You might want to ask the Roofing Company how such a situation would be handled.
Bottom line: Shingles not laying flat on the roof means that mistakes were made.
Don’t accept any answers that avoid responsibility. It is 100% an error by the roofing crew.