When planning a roof replacement project, there are various ways you can cut costs. One popular method is to lay new asphalt shingles over the old ones. This technique eliminates the cost of tearing down and disposing of the old roofing. While it may be affordable, it isn't always the best choice. It is advisable to tear down the old roofing and install the new shingles on top of the sheathing. Below are some problems that may arise if you place new shingles on top of old ones.

No Visual Inspection

It's crucial to inspect the old roof before replacing it. You need to establish the condition of the underlayment and roof decking. If your roof suffered moisture damage, the water could have penetrated a worn underlay and damaged the frame as well. Installing new shingles over the old ones prevents you from examining the damage. Consequently, the new roof will fail shortly after, leading to costly repairs. Removing the old materials allows you to inspect and fix underlying issues before laying the new shingles.

Inadequate Roof Prep

A roofing structure requires adequate preparation before laying new shingles. You must remove the vents, ridge caps, and old flashing. When you lay new tiles over the old ones, you don't remove any components because you want the old tiles to remain intact. Furthermore, you cannot replace the underlayment or install new insulation. With a complete replacement, you get rid of old and worn components and prepare the roof for the new shingles. You can also replace insulation and underlayment. As a result, your new roof will last longer and perform better.

Extra Load on the Structure

Most asphalt roofs are designed to handle a single layer of shingles. When you layer new shingles over the old ones, the load on the structure doubles. If your roof is old, its frame may fail to withstand the extra load. If your area experiences snow, the weight of the snow may ultimately cause the roof to sag and fail. Therefore, get rid of the old shingles to extend the lifespan of the replacement roof.

Diminished Aesthetic Appeal

Old shingles have caps, ridges, and overlapping pieces. Some shingles are also warped or curled, adding texture to the roof. If you install new shingles over the old ones, the surface defects may transfer to the new shingles, ruining their visual appeal. As the old shingles continue to wear out, they will undermine the appearance of the new ones. Therefore, get rid of the old materials to preserve the appeal of the new roofing.

To optimize the performance of your new roof, get rid of the old shingles and other worn components. For professional roof replacement services, consult a roofer.

Share