Top Reasons Why You Shouldn't Layer Asphalt Shingles Over an Existing Roof

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 Layering roofing has been a way to save time and a little bit of money when you need to replace your roof. However, layering roofing can void shingle warrantees, add excessive weight to the structure of your house, and diminish the overall life of the roof.

Before considering layering roofing over an existing roof, check your local building codes. Many restrict the amount of times you can layer the roofing, so chances are if your roof already has more than one layer of roofing, you're ineligible.

If you only have a single layer of roofing currently, and your home is fairly new, structurally the home will probably withstand the extra weight.


However, I've seen older homes that experience severe settling after a second roof is added over the first. I've also seen roofs that are made ineligible for layered roofing because the warping and cupping of the existing roof would damage the new shingles.


Buy Quality Roof Shingles

The biggest mistake people make when layering roofing is to purchase cheap shingles for the new roof. They seldom consider that in 15 years, when their roofing once again fails, they will have to pay significantly more to have someone remove both layers of shingles and apply new ones.

Savvy homeowners, or at least their home inspectors, are aware of this fact and may balk at buying a layered roof. Home inspectors are also aware that the thicker the roof, the less hold the roofing nails have in the sheathing. In a high wind situation, this can mean the difference between the shingles staying on, or being pulled off the roof.


Layered Roofing Shingles Fixes Leaks: True or False?

One misconception is that layering roofing will eliminate old roof leaks. Although this sometimes occurs, it is my experience that an unexplained leak will eventually reappear, even after new roofing is applied. For this reason, you should fix any problems with your old roof and be sure to address any leaks before starting a new roof.


Adding Layers of Roof Shingles Saves Money: True or False?

Most people want to add another layer to their existing roof to save money. However, this is a particularly short sighted approach when they realize that layering roofing can often void the warrantee. Manufacturers believe that layering the roofing diminishes the overall performance of the roof: ignore their advice and you'll find your 50 year warranty worthless. If the manufacturer claims to not have a policy against layering, get something in writing from the company that promises your warranty will not be voided if there is a problem.


Don't Skimp on a Cheap Roof Job: Go For Quality!

Where there are many places to cut corners in home maintenance, replacing a roof should never be something you do on the cheap. A bad roof can be the source of extensive and expensive problems that can severely diminish the value of your home. Instead, try to buy the best roofing you can afford and be sure to budget a little extra so the old roofing comes off before the new shingles go on.

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1 Comments

Porter said:

Does Amy consider herself a roofing expert? If so, what about considering the pros and the cons? One significant thing she overlooks, besides the cost savings, is the green advantage. Not only are you keeping more waste out of the landfill, but an extra layer of shingles does add an insular effect. If your house cannot withstand an extra layer of shingles, no doubt it was built very poorly. She suggests that you must be buying cheaper shingles, if you're doing a roof over. That is simply a supposition. Roof overs save time and money, and if you expect your house is in an area that may be subject to development or becoming commerical sometime in the not too distant future, what's the downside? Have a great day! PTLJ! >>

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  • You can see the raw edge of the siding from this angle.
  • A quarter dollar is 15/16" in diameter, used here for scale, to show the 3/4" thickness of the siding.
  • This cypress lap siding is planed smooth for this Victorian application.
  • Solid 3/4" cypress lap siding is used throughout the exterior of this Victorian Home
  • master bathroom suite
  • furniture sink vanity in bathroom
  • Palmdale entry with side lights and transom window
  • Palmdale foyer with alcove
  • laundry room with deep sink
  • Palmdale optional 3rd full bath upstairs
  • Palmdale master bathroom with walk-in closet
  • powder room with unusual sink

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