In a world that has been largely conditioned to think that bigger is better, that is not always true in all situations. Bigger has been found to be more wasteful in many cases, especially as efforts are made to conserve energy and be greener. While there is often something good in abundance, sometimes more can ruin a delicate balance, even with a roof. At first glance, it might seem that a double-layer roof would be better; however, this is not necessarily the case. Sometimes more in terms of roofing does the exact opposite and can actually be harmful, not good.

Concerns

The main reason for adding another layer of shingles to an existing layer is convenience and cost reduction. The price difference can be substantial so naturally the option of simply adding a layer will be considered. There are some benefits to this method, such as increased insulation and protection from the elements. Apart from these two, it is less beneficial to add another layer for these reasons.

• Weight – Probably one of the most important concerns is the weight of the material. Shingles are not lightweight by any means, so the structure underneath the top of the building must be strong enough to support the number of layers that are laid. A contractor should know this based on building codes. Saving money at the risk of collapse is not worth it and will cost more in the long run.
• Heat build-up – More insulating properties for a building may be useful; however, shingle layers can also cause heat to build up between them, leading to premature aging. If that happens, another coat or complete demoulding will have to be done earlier than if a completely new roof had been installed initially, ending up with no cost savings in the long run.
• Leak tracking – It is hard enough to find the source of a leak with a layer of roofing material. Multiple coats will only compound that problem and potentially create a problem when roofers try to find it. A completely new roof is likely to be needed and will not offer real savings in the long run.
• Tear – The initial reason most people choose to re-cover the top of a building rather than rip it off and start over is cost. Eventually a cut will need to be made, and when it does the cost will be much higher than an initial cut would have been before adding multiple layers. Labor and disposal fees can double in this situation and will likely cost more money in the long run.
• property value – For all of the above reasons, a layered roof will also negatively affect a property’s resale value, as real estate agents and home inspectors know that there will be a major repair very soon.

While it may seem like putting new material on top of a defective roof can be an inexpensive way to handle such a problem, it will likely cost more in the long run. While the cost of replacing a roof can be overwhelming, it is a wiser economic decision to do a full cut in conjunction with shingles, as it will save thousands of dollars overall. By doing a complete job, contractors can also closely examine the deck surface, check for evidence of undetected leaks, and make a more efficient home everywhere.

When working with a reputable and knowledgeable contractor, your best decision is to follow their suggestions if a full cut of the top of the building is the smartest choice. For the longest lasting roof and the fewest expenses over its life, a single coat is a better option than a double coat for any roof!