In days gone by, it was fairly common (even standard) to run new roofing shingles on top of the old ones to avoid the extra mess, expense, and hassle of a tear-off job. But today, it's hardly ever done anymore - and for good reason.
The fact is, while you gain a little in convenience and cost-savings in the short run, you lose out big in the long run when you put new shingles over old ones.
Here are the 8 top reasons why you should always de-roof before you re-roof:
1. Shingle Damage
Asphalt shingles are designed to lay down flat to the roof decking, and when they're laid over existing shingles, they can't lay properly. That can lead to shingle life span being shortened, as shingles more easily crease, crack, or slip loose in high winds.
2. Extra Weight Strain
Even one layer of shingles adds a great deal of weight to your roof, which the rafters must bear continually. Double that weight by having two layers of shingles, and you add unnecessary strain to your building.
3. No Decking Inspection
You can't properly inspect the existing roof in preparation for installation of new roofing if you don't strip it bare by removing the old shingles. Only then can roofers see where plywood may need to be replaced or where a potential leak point can be caulked or otherwise plugged up.
4. Less Leak Protection
In most cases, there will be not underlayment put on when you are just running shingles over shingles. And even when it is installed, it can't be done optimally since underlayment is, after all, meant to "lay under" the roofing material. This exposes your home to a greater chance of developing a roof leak and makes it much more difficult to locate and repair a leak should one occur.
5. Ultimate Higher Costs
While you might save a little in the short term, adding layers to your roofing will cost you as much or more later when you finally do have to remove two or more layers of shingles before putting on a new roof. The cost of tear-off and disposal will be doubled when you finally do have to get rid of your doubled-up shingles!
6. Warranty Worries
Another problem with "just going over" is that it could mean your warranty is over. Manufacturers of roofing materials may specify that the warranty no longer applies, at least not in full, unless the previous layer of shingles is removed prior to installation of their product.
7. Building Code Violations
In some states, counties, and municipalities, it is a code violation to lay new shingles over old ones. In other locales, you might be allowed up to two layers only. In areas of Florida with high storm risks, codes are often strict in this regard.
8. Loss Of Resale Value
Finally, if you plan to resell your home someday, having a two-layer roof is a big drawback. It can reduce the resale value of your home and make it more difficult to find an interested buyer. After all, it would be the new homeowner who would end up having to (eventually) tear off two layers of roofing.
For more tips and advice on roof repair and replacement for Central Florida, contact contact Sheegog Contracting today!