7 Problems with Two Layers of Shingles

7 Problems with Two Layers of Shingles

Are you thinking about installing another layer of shingles on your roof? While adding another layer may seem like an easy solution, it comes with some serious risks that should not be ignored. From increased weight and leaks to decreased lifespan and potential code violations – double-layered shingles may cause various issues.

In this informative article we’ll cover the seven most frequently occurring issues associated with adding another layer of shingles to your roof and provide valuable insight to help make an informed decision regarding its needs – don’t take chances with your home’s roofing needs – read further to gain knowledge!

Here Are Seven Issues With Two Layers of Shingles:

Installing new shingles over old can seem like a cost-cutting and time-saving strategy for homeowners, but this decision comes with its own set of issues that could require expensive repairs or even roof replacement in the future. We will cover seven issues associated with two layers of shingles as well as strategies to avoid them in this article.

Two layers of shingles refer to the practice of installing new shingles over existing layers on a roof, to save both money and time by forgoing the removal of old shingles. Unfortunately, however, this practice often causes more problems than it solves over time.

Problem 1: Increased Roof Weight

One of the primary drawbacks associated with installing two layers of shingles on a roof is their added weight. Shingles are heavy and installing multiple layers can drastically increase its weight; too much pressure could put undue stress on its structure and lead to its collapse or at the very least lead to significant sagging or collapse of its structures.

To avoid this problem, it’s essential that a professional roofer conduct a roof assessment and ascertain if it can support additional weight. If not, then removing old shingles and installing new ones might be your safest bet.

Problem 2: Reduced lifespan of new shingles

A bottom layer of shingles can dramatically shorten the lifespan of its top layer, decreasing durability and longevity significantly. By holding in moisture and heat, this layer may cause its counterpart to deteriorate quickly, leading to costly repairs or even roof replacement costs.

To avoid such issues, it’s imperative that the old layer of shingles be removed before installing new ones – this allows the new shingles to lay flat and secure without impediments that might cause damage.

Problem 3: Decreasing energy efficiency

Two layers of shingles can adversely impact roof insulation, decreasing energy efficiency. Air pockets between the layers may trap heat in the summertime and cold air in winter, making it harder for an HVAC system to regulate temperatures effectively.

To avoid this issue, it’s vital to remove old shingles before installing new ones, so proper insulation can be installed and improve energy efficiency in the home.

Problem 4: Increased Leak Risk

Two layers of shingles can increase the risk of leaks by trapping moisture beneath them and blocking proper drainage, leading to water damage in your home’s interior. Furthermore, their increased weight may place too much strain on an already fragile roof structure, potentially cracking it and allowing water seepage.

To prevent such problems, it’s essential that old shingles be removed before installing new roofing shingles – this allows your roofer to inspect its structure and ensure proper drainage.

Problem 5: Replacing roof shingles could become more challenging in the future

Installing two layers of shingles can make roof repair on damaged shingles in the future more complicated. Due to limited access to repairs or replacements, replacing the top layer may become increasingly challenging and time-consuming.

To prevent this problem, it’s vital that old shingles be removed prior to installing new ones. This allows easier access to the upper layer and makes repairs or replacements much simpler.

Problem 6: Building Code Infringements

Installing two layers of shingles may violate building codes; most codes stipulate that only one layer should be installed on roofs, and any violations could lead to fines and costly roof repairs.

To prevent this problem, it’s essential that roof installations abide by building codes and guidelines – this will ensure it’s completed legally and correctly.

Problem 7: Voided Warranty

Installing two layers of shingles may void a manufacturer’s warranty, as most warranties require that only one layer be installed on a roof. Violating this requirement could void it, leading to costly repairs or replacements.

For optimal roof installation results, it is vital that the roofing contractor follows manufacturer-provided installation guidelines. This will ensure their warranty remains valid should any repairs need to be made.


Although installing two layers of shingles might appear cost-effective, installing them may create more issues than it solves. From leakage risk to increased energy bills, installing multiple layers outweigh their advantages.

Prior to installing a new roof, it’s essential that old shingles be removed first. This will ensure your new roof has an extended lifespan, remains structurally sound, and looks professional. Don’t take shortcuts when it comes to roofing; invest in quality materials and roofing contractors to install your roofing shingles for optimal protection of both home and family.