Buying A New Roof Part 2 – Assessing Your Current Roof

August 14, 2013 | Filed under: Buying A New Roof series, Roofing Help, Roofing Help Videos

Hi, I’m Todd Miller of, and this is my second in a series of videos on How to Buy a New Roof. This is part 2. If you watched part 1, you learned about how it’s very important to know what your criteria are when you’re buying a new roof; know what it is that you want to accomplish with the new roof that you didn’t have with your previous roof. If you don’t determine what it is that you want to be different in the future, you can be pretty well be assured that your future’s going to be a whole lot like your past, which means in a few years you’ll be right back to looking for new roof again.

This time in the second of our series on How to Buy a New Roof, I wanna talk about how you can go about assessing your current roof. You need to know what the current condition is of your current roof in order to be able to talk intelligently about it, and in order to make sure that contractors that you invite to talk to you are really telling you the truth and being straight up with you.

Understand your Current Roof

First of all, in assessing your new roof, I really suggest you just take a walk around and understand your roof. Understand what I call the geometry (or the shape of your roof) in terms of the the physical shape of it, the physical dimensions of your roof. Don’t get up on the roof. Do this all from the ground. If there are roof areas that you wanna see better, take a pair of binoculars with you. Sometimes if you have a multi-story house you might be able to get a look from an upper window and look across the lower roofs to get a better feel for what’s going on with those lower roofs. Again, take a walk around your roof; take a hard look at it. Look for anything that is unusual. Look to see if there is streaking and staining on the roof, Look to see if there’s any unusual areas on the roof.

One of the real tricky areas at some houses have is what we call a dead valley, meaning that you’ve got a portion of the building that runs up through the roof, and the roof literally runs into, it so that the water as it drains down the roof ends up running into a part of the house. Those are very very tricky areas when you have them. You want to make sure if you’ve got those areas that your aware of it and you’re able to talk to your contractor about exactly how they’re going to handle that area of the roof.

Take a look in your attic. You wanna look really well at the underside of the roof decking in your attic. Another thing is if you get up in the attic and you see that you’ve got what we call spaced sheathing (meaning you don’t have solid decking or solid plywood covering on your roof), you want to be aware that. So take a look in the attic, look for any leaks, look for any areas where you might have a lot of mold or mildew growth on the bottom side at the roof deck. These are all things that you’re gonna wanna talk to the contractor about.

Additionally, if you have any roof deck that is in bad shape from a leak or you’re seeing mold or mildew on it, that may indicate areas of your roof where that decking is going to have to be removed and replaced. You won’t want to just keep that old perhaps spongy or even downright rotted decking in place.

Take a look at your attic insulation. See if that insulation in particular is blown into the overhangs of the house. Ideally, and I’m going talk more about this later in a future video, but when you re-roof your house, It’s a good time to look at the ventilation needs in your house, and ventilation requires two things: it requires intake vents which are usually located in the overhangs down at the bottom of your roof, and good ventilation also requires exhaust vents, which are typically going to be at or very near the peak of the roof. So when you’re up in that attic, take a look at your overhang, and see if the insulation is pushed into the overhangs. If it is, and you have intake vents in your overhangs, there’s a chance that that insulation over the years has gotten pushed, or moved, or blown into those overhangs (so it’s actually blocking those intake vents), and that’s not a good thing. Those intake vents need to be clear and open and have air coming through them. So you wanna make sure that you take a look at the insulation, take a look at those overhangs, and if those overhangs are full of insulation, at the time of re-roofing is the time to get those cleaned out and make sure that air is flowing through them properly.

Again, look for difficult areas on your roof (I talked about blind valleys earlier) but things like chimneys, things like skylights. Honestly, skylights are kinda of a pet peeve of mine. I’m not a fan of them. Yes, it can be done properly and skylights can be flashed so that they are worry-free and trouble-free, but on the other hand they are an area where problems can happen, and so I’m not a fan of skylights. If you got a skylight, you might want to think about do you really need it? Is that really something that you wanna have?

Additionally, skylights are notoriously very energy in-efficient. They tend to let heat and cold through them both ways, so in the summer they are drawing heat in your house, and in the winter they are letting the heat out of your house. So both those things are also not good in terms of skylights.

Take a look at the pitch of your roof, if you’ve got any areas of your roof that are very low pitch. Pitch is measured in terms of rise over run, and typically the way the roofing industry does it is we’ll look at a run of 12 feet (and run means the horizontal progression through your roof). So if you were to stand at the edge of your roof and you were to visualize 12 feet back into your roof, that is the run. And then you you want to look at what the rise is. The rise would be the vertical rise within that run. So, if the roof is rising 3 feet within that 12 foot run, you have what we call a 3/12 rise-over-run 3/12 roof pitch.

Standard shingles require at least a 3/12 roof pitch. A lot of metal roofs require at least a 3/12. Wood shake should be installed on a 3/12 same with slate and many other materials. So if you’ve got a roof pitch that is less than 3/12, that’s an area you’re really gonna have to think about, and talk to your contractor about. There are metal options that can be used on a roof pitch that is less than 3/12. There are also various TPO PVC rubber membrane type materials that can be used on those lower roof pitches. Don’t listen to the contractor that says “Don’t worry about it, we’ve got a way to make that product work on a lower pitch than it should.” Absolutely and under no circumstances should you ever let someone install a roofing material on your house at a lower pitch than what the manufacture of that material says it should be used. Manufacturers want to sell their products. If they tell you “Don’t use it at a pitch lower than this,” then absolutely it should not be used at a pitch lower than that. They’re not making that up, they are not joking about it. So never let a contractor use a roofing material on a pitch lower than what the manufacturer says it should be used.

Finally as you assess your roof, look and see how many layers of roofing are on it. Now, you can be deceived by that, because sometimes on the bottom edge of the roof (what we call the eve of your roof) there can be a double-layer of shingles, and that was the way that the original roof was installed (with two layers down there). You wanna take a look to really know how many layers of roofing are on your house. Realize that building code in most areas says that you should not have more than two layers of roofing on your house. So if you’ve got two layers, you’re gonna want to do a tear-off.

Now additionally, if you’ve got even one layer of standard shingles, and you’re looking at putting on a standard single roof you might want to think very hard before you let someone talk you into putting a second layer over your original shingles. Putting another layer of standard shingles over an existing standard shingle usually will void the warranty on that new roof, and it also will usually shorten the life for the new roof. Now. things like metal roofing can be easily be installed over old roofs without voiding any warranties, without shortening the life. So that’s one of the benefits that I really like about metal roofing, is the fact that you can install over old or existing shingles. Obviously if you have to tear off your old shingles and dispose of them in a landfill, that’s done at expense. It’s not cheap. It’s also relatively messy. It’s how you end up with nails and debris in your yard, or perhaps shrubbery that gets broken from from removing old roofing materials from your roof. So, I like metal because you can go over the old shingles and not have to do those things. What I often tell folks is “With the metal roof you can invest your money in a better roof (an investment-grade roof really) rather than invest your money in tearing off and disposing of the old roofing materials.

So again, this has been our Part 2 of my video series on How to Buy a New Roof. In Part 1 we looked at making sure that you know what your criteria is…what it is that you care about; what it is you want to accomplish with your new roof. Here in Part 2 we took a look at assessing your current roof… fully understanding your current roofing situation before you go out and start investigating products, and certainly before you go out and start talking to contractors. You want to make sure that you fully understand what your situation is, so you can talk intelligently about it, and so you don’t have contractors perhaps tell you things that are not true about your roof.

Again, feel free to call me or email me anytime you have questions. Send me pictures of your roof, I’ll be happy to help you assess it. Again you can find me on the web at, and you can email me very easily at You are also welcome to call me here at my office anytime at 1-800-543 8938 and I am at extension 201. So thanks again for tuning in. I wish you the best as you start this journey of buying a new roof, and stay tuned for future episodes on How to Buy a New Roof.

todd Miller

has spent his entire career in the metal building products manufacturing industry. He is president of Isaiah Industries, an organization recognized as one of the world’s leading metal roofing manufacturers. Todd is currently Vice President of the MRA (Metal Roofing Association) and a Past Chair of MCA (Metal Construction Association). Through his website, he strives to raise the bar on standards and practices to provide property owners with the best possible products for successful roofing projects.

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