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New Shingle roof – Can you save money on your new roof with a layover?

Often, when we are performing a shingle reroof for our customers, we find a second layer of shingles beneath the top layer. Many of our customers in the West Palm Beach area ask if it makes sense to just lay a new layer of asphalt shingles over the existing layer to save some money. Our answer is always “No”, and here’s why:

-When you reroof a shingle roof or tile roof, you remove all the material down to the plywood, as code updates have occurred over the years, and it’s important to update the nailing schedule on the plywood decking. Aside from better resistance to wind pressures during a hurricane, updated nailing patterns on the decking are an important factor in Homeowner’s Insurance rate calculations.

– If you leave the old shingles, you are leaving behind all of the rotted or damaged wood underneath that should be replaced.

-When nailing new shingles over old, nail penetration issues are common. With the extra layer of material, nails may not penetrate in to the plywood as far as needed. Conversely, because shingles are softer than plywood, the “cushion” created by the first layer of shingles can allow nails to be “overdriven” into the new shingles. When nails are overdriven in the new shingle, they tear and are more likely to go airborne under strong winds.

– Moisture trapped between the new shingle layer the old can speed the degradation of the new shingles on your new roof. Moisture and heat are enemies of asphalt shingles. The second layer of shingles increases heat and moisture retention, essentially baking off your new roof faster.

Roof Repair Advice

In our opinion, the money saved by not removing the old shingle layer is lost over time by the increased frequency with which you must replace your roof. Plus, you cannot overlay asphalt shingles a third time, so the next time you reroof, you will have to tear off, and a roofing contractor will charge for the extra layer of tear off.

If you have an aging shingle roof and are considering replacing your roof with new shingles, don’t consider laying over the existing roof.

Areas of South Florida such as Palm Beach Gardens, Jupiter, and Boynton Beach are replete with neighborhoods with picky Homeowners Associations and tile roofs that get dirty. Dirty tile roofs and picky HOA’s a good combination do not make.

The “dirt” most homeowner’s see on their tile is actually algae. Because concrete tiles are porous, they absorb water and create a nice area for algae to take root. Slopes of the roof that get the least amount of sun get even more algae growth.

south florida roof maintanenceMany of our clients ask what we recommend for keeping their roof clean and keeping their HOA off their backs. We always recommend avoiding high-pressure washing methods. Tile roofs have many areas that water penetrates beyond the tile. A 3000psi jet of water that shoots into a crevice in your roof can cause damage by literally tearing or slicing right through the underlayment. With the underlayment damaged, your home becomes highly susceptible to roof leaks. Damaged roof tiles are another common issue after a roof cleaning. Because roof tiles are typically only supported by the tile below it, it is important to only step on the lower third of a tile. Always make sure you hire a professional to clean your roof and make sure they use methods that will not cost you more money in the long run.

There are options in roofing materials to avoid the algae buildup on tile roofs. When buying a new tile roof, avoid the “combed” flat tiles shown in the picture. These tiles have grooves that run through the surface of the tile, creating even more surface area and places for algae to grow. The other option is to select a clay tile roof. Although more expensive, clay tile is naturally algae resistant.

In South Florida, concrete tile roofs are extremely common, and in some areas such as Palm Beach Gardens, Jupiter, and Wellington, tile roofs dominate the landscape. When a client calls our office with a tile roof leak, one of the first questions I like to ask is how long has the leak been noticeable from the inside of the home. The most common response is “I’m not sure, I just noticed it”.

south florida tile roof repairThis makes a lot of sense, since most people don’t walk around their home, staring at the ceiling. Typically, when water has entered the attic in sufficient quantity to soak through insulation and drywall, more significant damage has already occurred to the roof structure. This photo shows the level of plywood and truss rot in an attic we recently repaired. The roof leak seemed small because, from inside the living room, the area of drywall that visibly showed water damage was less than one square foot.

Although nearly every repair we perform on a tile roof show evidence inside the home, there is very rarely any sign of tile damage on top of the roof. This is because the concrete tile is not actually performing the role of a water barrier. On a tile roof, what truly protects the home from water is the underlayment.

south florida roof repair tileThe proper way to repair a tile roof leak such as the one pictured is to remove the tile over the leak and the areas surrounding it. Then, we remove the damaged underlayment to expose the damaged wood below. After cutting out and replacing the damaged wood, new underlayment is installed, using the best materials possible to ensure that the repair outlasts the rest of the roofing system. This is the more costly way to make repairs, but it’s the right way.

Frequently, homeowners will get low bids from a roofer, who plans to remove the tile and apply some roofing cement over the damaged underlayment and replace the tiles. I like to call this approach the band aid approach to repairs. What happens when you stick a band aid on a severe cut? It usually holds back the flow for a few minutes until it gets wet and falls off…

When it comes to a leaking tile roof, be sure to hire an expert that will perform the work the right way, from the beginning. A cheap repair often becomes much more expensive when it doesn’t last and causes damage drywall and wood damage that must be repaired a second time when your roof leaks again.

Roof Repair start with a proper assessment.  Exactly what do you need, what will it cost, how long will it take?  Call a professional in Jupiter.


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