There are a lot of advantages when it comes to installing shingle in a vertically at the top of roof. This is because it’s much faster.
Staggering or Vertical Racking
In trade it is known as staggering or vertical racking, this method enables the roofing contractor to install a single column of shingles all the way to the top, without going back-and-forth to fill several rows of stair steps.
Also, the shingles can be piled just to the side of the column being laid. This saves some much time when moving shingle bundles. After finishing a column, the roofing contractor can go back down to the eave edge of the roof and start laying the next column of shingles.
The two step shingling and racking will produce watertight roof. You are not going to lose your warranty by going with the racking method, although, with some producers, you’d have trouble with two specific problems: shadowing and pattern-curling (that is color blending).
Pattern curling occurs when the roofing contractor lifts one side off every other shingle to install the last shingle nail in the end of the next shingle. Inasmuch as the bending can stress and change the form of shingles (especially when the weather is cold), over time the shingles may wrap at the ends, bringing about some visible pattern on the roof.
If the shingles manufacturer doesn’t allow racking, you are less likely to receive any warranty.
A patchwork appearance is caused by little color differences among a bundle of shingles is known as shadowing. This has its own problem, when shingles from one bundle wind up in vertical rows it is usually the worse racking method. Richmond Va roofing contractors are expert in this method.
A slightly different color from a nearby shingle can lead to the roof looking patchy—even striped. The stair-step format does spread and mix the bundles much better.
To prevent shadowing, make sure you check all the bundles are from the same lot and not just the same color. However, some in some cases it does not matter because some manufacturers’ color blends are very consistent that they don’t have or need lot numbers.
Make sure you check the instructions on wrapper of the shingle. Some suppliers or producers make shingles that can be used with either shingling method, but they have two sets of instructions to ensure an even color pattern. If you don’t find the instructions very clear, call the supplier to find out if shingles racking method is acceptable or not.