Issues You Might Encounter
Once youve made the decision to go with metal roofing over shingles, you will have several different issues to keep in mind:
- Building codes
- Condition of existing asphalt shingles
- Ease of installation.
In terms of building codes, many municipalities now have placed limits on the number of layers of roofing a residential building can have before requiring a complete tear-off.
Usually this number is two, meaning that if your roof already has two layers you wont have the option of installing a metal roof over shingles until youve removed at least one of the layers.
Shingle condition also plays a role, since a large number of missing, deformed, or curled shingles may narrow your options, requiring you to use a steel shingle system rather than a standing seam steel system.
Also, if the existing shingles on top are not level or in very poor condition, you may need to put a layer of roofing felt down or wooden frame over the shingles before installing the new metal roof.
In terms of aesthetics, you need to be careful in terms of choosing your metal roof solution so that it will blend into your surrounding neighborhood.
The traditional concern, of course, is that a metal roof will make your house look like a barn or storage shed if not done properly. But thanks to many different choices in color, size and shape, this is no longer a major concern.
Metal roofs on houses can look very attractive and dramatic.
Detail : Ventingthe Ridge
Cool outside air travels under the shingles to the vented ridge, pulling out moisture and heat.
A steel roof is a lifetime investment, lasting 50 years or more if its a good one. Asphalt roofs typically last 20 to 30 years, depending on the installation and shingle quality. So, the investment might be worth it, but the range of choices makes shopping for a steel roofing system more complicated than you might think.
If you want to install steel over asphalt, your best choice for installing metal roofing is to use a steel shingle system like the one shown instead of the more common standing seam steel. In a standing seam roof, long, single panels run vertically all the way from the eave to the ridge. In contrast, steel shingles are small panels installed in horizontal rows much like other shingles.
Better steel shingle systems, like the one shown, install over a framework of 2x2s. This framework has three big advantages. First, because the frame is screwed directly to the rafters and the interlocked shingles are screwed to the frame, the roof can withstand winds of up to 120 mph without damage. Second, the frame creates a flat and straight surface even when the shingles are badly curled or the roof ridge is bowed.
Determining If A Roof
You should have your roof inspected by a professional roofer to check for the following:
- Leaks or issues that need to be resolved
- Wood under the shingles is not rotted
- The condition of the shingles
- How many layers of roofing are already on your home
In addition to checking the condition on the current roof, you, or your roofer, should confirm with the county that more than one layer of roofing is permittable.
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Can Metal Roofs Be Installed Over Shingles
In simplest terms: Yes, you can install a metal roof over shingles. However, youll want to check with your local building department before you make any decisions. Building officials in some areas will only allow a re-roof over one layer of shingles, while officials in other places may allow you to place the roof over two layers of shingles. Fortunately, in most areas, it wont be an issue if youre only going over one layer.
Not a real zip code.
Section 1511.3.1 of the 2018 International Building Code 1st Edition states, The installation of a new roof covering over an existing roof covering shall be permitted where any of the following conditions occur2. Complete and separate roofing systems, such as standing-seam metal roof panel systems, that are designed to transmit the roof loads directly to the buildings structural system and that do not rely on existing roofs and roof coverings for support, shall not require the removal of existing roof coverings.
So, its possible to have the installation of metal roofing over shingles, which is great news! But you might be wondering what the advantages and disadvantages are and what to keep in mind during installation. Keep reading to find out.
What Does Installation Involve
Before any installation, your roof will need to be checked for any major problems. Any major problems will have to be fixed before installing a metal roof over asphalt shingles. Such problems include:
- Rotted wood deck
- Cracked or broken shingles
Once these issues have been resolved, installation can begin. Each roofing contractor will have their own way of doing things. Talk with your contractor if you are concerned about their methods.
For this type of installation, a new underlayment will sometimes be installed before working on the metal roof. After this, the metal roof can be installed. Most often, furring strips will be used to secure the new roofing to the shingles.
Once the roofing is on, edging will be installed to bring it all together.
To learn more about our installation process for metal roofing, Tampa residents can contact Affordable Roofing Systems at 542 8462.
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Interested In Putting A Metal Roof Over Shingles
All in all, it is absolutely possible to put a new metal roof over an old shingled one under the right circumstances and conditions. Not sure if your current roof is up for it? Give Werner Roofing a call!
If youre considering a metal roof, wed be happy to assess your current shingle roof to determine if its a good candidate for laying a metal roof overtop. You can count on us to give it to you straight and only make recommendations that are true to your roofs condition. We always try to save you money on your roofing project wherever possible like our free inspection, for instance! Contact our team to schedule yours today.
Manufacturer Warranty And Specifications
Some manufacturer warranties will not cover the metal roof if you install it over asphalt shingles. Some manufacturers may offer a warranty but exclude coverage for any problems that are related to the asphalt shingles. Make sure you understand the conditions of the warranty before you purchase the metal roof.
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Allow The Professionals To Do It
So while you might save some time and money on placing your new roof over the old one, you could encounter extremely large issues that would result in you spending more time and money on your roof than you would have if youd removed the original roofing materials at the start of the project.
Ready To Upgrade Your Roofing
Interested in making the switch to metal roofing? Trust Long Roofing for the job. With a Class 4 distinction in impact resistance and a Class A fire rating, our metal roofing is made to withstand a variety of damaging forces. More durable than wood, slate and asphalt, as well as algae, rust and mold resistant, your metal roof from Long Roofing is sure to last a lifetime.
Call 866-270-7058 or contact the Long team online today to get a quote, schedule a free, in-home consultation or find answers to any of your roofing questions.
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Your Decking Is Covered Up By Your Old Asphalt Roof
When you get a full roof replacement, your old roof is torn down to its decking. This gives your contractor a chance to inspect the deckings integrity to see if it can handle your new roof.
If you install a metal roof over your asphalt roof, theres no opportunity to inspect your roofs decking. If your contractor cant test your deckings integrity or inspect for rotten boards, it could lead to a costly problem down the road.
I understand everyone is on a budget, but if youre investing in a metal roof you might as well tear-off your old asphalt roof to avoid this problem.
Ensure The Condition Of The Existing Shingle Roof
The condition of your existing roof is also crucial to consider. Covering the area with metal sheets without repairing the damage can lead to more significant problems. The first thing to do is check the condition of the existing plywood, ensuring there are no soft spots that can affect the hold of the screws which mount the metal in place. Also inspect your roof for signs of breakage or shingle damage caused by leaks.
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Ridge Vents Are More Obvious
On most homes today, attic venting is provided by a continuous ridge vent that runs across the peak of the roof. On a shingled roof, this continuous ridge vent is a strip of shingle-like material that runs the entire length of the peak of the house, masking outflow holes on the sides of the ridge. You likely have seen this countless times, but probably never really noticed because the CRV usually lies very flat and blends in perfectly with the surrounding roof.
On many metal roofs, especially standing-seam roofs, the CRV is also metal, and it stands out further and is thus much more noticeable. These thick, prominent lines or ridges are inherent in metal roofs and add to their distinctive look.
Check Whether Moisture Can Get Trapped Between Roofing Materials
A big reason people install metal roofs is because they are mildew and rot-resistant. But if moisture can get between your metal roof and your existing asphalt shingles, that great benefit is non-existent. Moisture between your roofing materials will still lead to mold, mildew and rot.
Ask an expert about ridge vents and furring strips to prevent moisture from getting under your metal roof. Generally, your roofing underlayment is what prevents moisture from being a problem with your home and its materials. But the integrity of that underlayment could be jeopardized based on you placing the new materials over the old ones.
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Can You Put Metal Roofing Directly On Plywood
It is always best to put down an underlayment and a slip sheet before installing metal roofing on plywood. This extra barrier will protect the plywood from the metal roof.
Without the extra barrier, the wood can wear out. It will be more likely to leak as well as build up moisture on the metal roof.
Can You Shingle Over Existing Roof Shingles: Complete Guide
It is not uncommon for homeowners to roof over existing shingles this is called reroofing. New shingles can be installed or laid over the old ones when a new roof replacement comes instead of tearing off the existing roof.Heres what inspecting houses for decades have taught me:
You should only reroof over existing shingles if the roof decking is in good condition and there is presently only one layer of shingles on your roof. Adding more than two layers of shingles can cause the roof structure to sag under the weight. Its best to replace flashings when re-roofing.
On a typical day, a roof replacement would involve tearing off the old roof down to the decking to remain only with the roofs trusses or rafters, which sometimes need to be reinforced if damage or rot exists. In reroofing, none of this happens.
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Can You Install A Metal Roof Over Existing Shingles
Absolutely you can! Installing a metal roof over existing shingles rather than tearing the shingles off can have many benefits. However, before you can begin laying your metal, you should first inspect the existing roof to ensure it has the proper conditions to support a metal roof. You must also understand how to install over shingles.
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If you are considering installing a metal roof on your house, you should be aware of several problems that can arise when doing so. Its more difficult to inspect, it could create an uneven surface, and it can ultimately shorten its lifespan. Here are the details on some of the most important reasons why the existing shingle roof should be removed prior to the installation of a new metal roof:
1. The only way to inspect the roof decking and ensure theres a solid foundation for the new roof is by removing the existing shingles and stripping the roof down to the wood. Removing the old shingles gives the installer a clean start to building the new roof and it gives the roofing professional a more accurate view of whats going on beneath the hood. Inspecting for wood roots is important since this is where connections will be made and where sound insulation can be installed. This will also ensure that there are no hidden nails or other weaknesses that could let the breeze in or out through the wall, and if there are any signs of damage, like wood root, the entire roofing system needs to be rebuilt.
Making the switch to metal roofing is a big investment, so you shouldnt cut corners that will ultimately diminish the value of the new roofing system. When installing a metal roof, it really is best to remove the existing shingle roofing first to avoid any undesirable results.
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Exceptions To Putting Roofs Over Shingles
Of course, you cant always put other types of roofing over existing shingles, whether theyre metal or not. If the shingles have been covered over multiple times, the layers may have become too thick and will need to be removed before you can put another roof on it safely. You may also need to repair the roof if it has been damaged.
Putting a roof over shingles can only be an issue if the roof material is heavy enough to cause structural damage. Because metal is quite light, this is only likely to happen if there are many layers of asphalt shingles.
Keep in mind that were talking about putting metal over asphalt shingles. Wood shingles may be too thick to have metal roofs placed over them, as the wood shingles could deform the sheets. If the asphalt shingles arent even, this could also create other issues. If youre unsure, the best thing to do is contact a professional. Theyll take a look at your existing roof and the material you want to put over it and determine whether its the best option.
Question 3 Of : Do I Need Underlayment For Metal Roof Over Shingles
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Question : Why Leave Shingles When Installing A Metal Roof
Find a better roofing contractor. The old roofing should be removed, underlayment installed and furring strips screwed down for the metal to be fastened to. Dont let the installer screw the metal to plywood sheathing. It wont hold over time. If the old roof needs to be replaced why leave it there and not make sure there are no underlying problems before covering it over again? Also, the extra weight could be too much for your framing and cause cracking or other structural problems.
· Todd Shell, Angies List
1. Some metal roofing contractors are trying to convince people that you do not need roof wrap under metal roofing presumably so they can get their initial installed cost more competitive with other roofing materials. Dont fall for that metal roofs do leak at times, and without the roof wrap you have nothing to keep the water from saturating and rotting the sheathing and rafters, destroying your entire roof.
2. Also, if your roofing is flat sheet raised seam rather than corrugated, the batts or nailing strips should be discontinuous small gaps are needed every few feet to allow hot air to flow up to the ridge vent , otherwise it just becomes an oven between the roofing and the sheathing, plus the sheathing gets much hotter and makes your entire attic hotter in the summer.
3. It saves having to fill up landfills with old shingles.
· Unknown, Angies List
Question 2 Of : Can You Put Metal Roofing On Top Of Damaged Shingles
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