Installing new shingles to a roof can improve any building structurally, but also improves its looks and value. The process of installing the new shingles can vary, and a common question often arises “Can you install new shingles on top of old shingles?” There is a benefit to following this method but there are also negatives which must be addressed.
The clear and obvious benefit to installing new shingles on top of the old one is cost savings. The task of removing old shingles is labor intensive and time consuming. It is a messy task which involves special tools to remove the shingles and containers to dispose of the waste. Care must be taken to remove the edging, vents, and seals which were originally installed. The task can take a at least a day by an experienced roofing professional and cost, depending on the roof size, over $1000. Furthermore, sometimes the local municipality requires special permits or taxes to dispose of the shingles.
The much easier option is to just lay the new shingles directly on top of the old ones and avoid this delay and cost. But, is it really the best option?
One of the long term damaging effects of laying new shingles on old ones is that you cannot inspect the deck below the old shingles. The deck must be sealed properly to prevent rain damage and be inspected for mold, cracks or holes. The tar paper which lies between the deck and shingles is also vital to properly waterproof a roof. The only way to properly know if it is safe and sound is an inspection which is done after the old shingles are removed. Moisture, rain, and ice have ways of getting into the tiniest areas and causing large amounts of damage, so even if the old shingles appear to be in OK condition this does not necessarily mean the deck and tar paper under them are sufficient.
Shingles are designed to be installed on a flat surface. Since the top of the old shingles will be layered, the new shingles will not be properly installed in the way they were designed. This can cause further potential damage caused by rain and moisture, but also increases the likelihood of wind damage, since the wind can blow under the new shingles easier.
Another important factor to consider is maximum weight that the roof structure can hold. Shingles can add extra weight which might not be what the roof was designed to hold. A few other legal issues that can arise are zoning restrictions and jurisdictions that might not allow for 2 layers, and certainly not more. A final thing to consider is the shingle warranty. Good quality shingles come with warranties which might be voided if they are not installed as the first layer.
All things considered, while in the short run it may seem in your favor to save time and money by applying shingles on shingles, chances are your costs will outweigh your benefits down the road.
Save time and money and speak to a GAF Master Elite Queens, NY Roofer for a fast & free estimate on all roof maintenance, repair and installation services.
Royal Renovators Inc. 118-35 Queens Blvd Forest Hills, NY 11375 (718) 414-6067 https://www.nycrenovators.com/