Can You Roof Over Existing Shingles?
The short answer is yes, you are able to place new shingles over your old ones. Ok, so now that we’ve answered that initial question…let’s dive a little deeper into why you may or may not want to go through with doing this. However, it is worth noting that “re-roofing” is only possible with asphalt shingles…you cannot place new shingles over old shingles from any other material like wood or slate. Furthermore, it is worth noting that you should never mix roofing materials like asphalt and cedar or asphalt and ceramic. Finally it is important to make sure that your current roof is in good standing, otherwise it’s the equivalent of putting lipstick on a pig and expecting it to win the pageant.
Why Add New Roof Shingles Over Old?
Although it might seem very obvious what the benefit of new shingles might be, having many layers of shingles doesn’t really make it more waterproof or leakproof. In fact, some would argue that it causes its own problems altogether. So, just why would you want to place new shingles over the old ones? Choosing this option is actually convenient time wise and monetarily speaking. By simply just having the addition of new shingles, you get to miss out on the labor and time intensive step of tearing off the old shingles. Thanks to missing out on that step…you’ll save quite a bit of money!
Unfortunately, it doesn’t just stop there. Each of these benefits both have catches of their own. Although it’s clearly cheaper, there is some prep work involved to have a re-roof done on your home. For example, you will need to remove vents, messed up shingles, and ridge caps…on top of the flashing, which is known to be tricky over old roofs. If you opt to lose the tearoff you can save $1,000 or more…but ultimately, you’re just delaying a cost you’ll have to pay in the future. If you ever need to replace your current roof, you have no choice but to start over and you’ll have to pay a little extra for the now two layer tearoff and its disposal.
Why Not Add New Roof Shingles Over Old?
As we have introduced above, the list of cons for placing new shingles far outweigh the possible pros, but again, it all depends on your personal situation. The short list below includes a couple universal reasons why you shouldn’t want re-roof right away as well as some other things that should be taken into consideration if you are really thinking long and hard about adding new shingles over old ones.
1. Shingles are designed for flat surfaces. Regular shingles are just not the best at bridging over gaps or humps, and yes…that includes the stepped texture from overlaps. No matter what kind of tricks re-roofers will try when laying new shingles over old ones the same step up pattern will not be possible if the old shingles cupped, curled, or brittle. Even still if a re-roof is what you want, roofers in Colorado Springs suggest using dimensional shingles because they are thicker and can often hide any dips in your roofing that might be unsightly.
2. Shingles add weight. High-quality shingles weigh a lot more than you might think. Typically, in the range of 3.5 to 4.5 pounds per square foot. That may not sound like a whole lot…but that adds up pretty quickly especially when you have a big home. It is also important to understand roofing structure and how much yours can handle. Most roof structures are designed to be able to handle the one layer shingles, some snow, and a safety margin. Beyond that…adding a second layer is effectively doubling the weight and that may not be something your roof structure is able to handle. This reason alone is why many building codes in Colorado Springs limit re-roofing to no more than two layers. All that extra weight can cause the roof decking to sag which sounds as dangerous as it is.
3. No visual inspection of roof sheathing. The tearoff is what roofers need to see what the decking looks like. Most roofers worth their weight will complete what is called a “walking” inspection. This thorough walk on your roof is what they use to inspect for spongy areas or other roofing problems. Some of these problems can actually be solved before the re-roofing is done. Other roofing contractors in Colorado Springs may not be as thorough.
4. Can’t replace underlayment. Putting new shingles on won’t help if your tarpaper is old and worn down. If this paper is worn down, it won’t protect your roof from the extra water or snow that gets past the shingles. In snowy areas like Colorado, you have the choice of using a new rubbery membrane that, when applied, acts as a ice and water shield to protect against the formation of ice dams. Unfortunately, this is not an option you have with a re-roof. All that goes to say, new shingles won’t protect against ice dam formation!
5. Re-roofing may affect the warranty on the new shingles. Just because you get new shingles placed over old ones doesn’t mean there won’t be warranty outs in the fine print. Make sure to check with your manufacturer for any warranty questions and install requirements before investing all the time in a re-roof.
6. Local codes might not allow re-roofing. It is important to be aware of your local building codes. Like we had mentioned earlier, most areas limit the re-roofing to two layers…anymore than that and its not happening. Rules like this protect buildings in areas with heavy storms and extreme weather on a regular basis.
7. A re-roof might not look good on an inspection report. Are you planning on selling your house soon? If you are a re-roof may not look all that appealing on the inspection sheet. To many people, especially new home buyers, they see re-roofing as a patch fix. If an inspection report comes back like this, the inspector may warn the prospective buyer off which can be really disappointing. At the end of the day, we recommend reaching out to a real estate pro and roofing contractor to see what your best options are moving forward.
Give Roof Troop a call today for any roofing inquiries!
