What’s the Best Roof Underlayment? EXPLAINED by a Roofer!

Foreign. That big storm hits, whether it's a windstorm, a hurricane, hail, and your roof is at its most vulnerable and your home truly needs protected. That is where underlayment comes in. And that's what we're going to be talking about today.

Reimagine roofing was started five years ago because I wanted to help bring some professionalism to the roofing space. I came from the solar industry before and I just wasn't happy with the professionalism and the sharpness coming from the Marine Corps, I really found it important to have professionalism in everything I do. And so that's why I started reimagine roofing.

Underlayment is the last line of defense. And oftentimes that last line of defense is going to be the difference between having a watertight home and having an absolute disaster. So let's get into the different types of underlayment, the benefits of them, and how this affects you and your roof. First type of underlayment that we're going to talk about today. This is the oldest type of underlayment that is still being used. It's called a couple different things. Felt paper, tar paper, roofing paper. But basically what there is to understand about this is this is an asphalt based underlayment that's made up of other organic materials as well. It's very, very flimsy. It almost resembles construction paper. As you can see, super easy to tear. It's not very resistant to heat or humidity. As it heats up, it begins to contract, dry up, turn up, and then it becomes basically useless. The other big drawback of this is that it's, it's not very wind resistant while it is held down by cap nails. If the shingles get ripped off by a windstorm, this will also go with the shingles. Additionally, if the shingles are damaged by a large hail strike, the tensile strength of this underlayment is extremely poor and it would also be damaged. So when that shingle is damaged, whether it's by wind or hail, the expectation with your roofing felt is it's also going to be damaged, which leaves your house vulnerable. All right, next, let's talk about synthetic underlayment. This is a polypropylene underlayment, which is made from reinforced plastics. But what's really interesting about this is it has about anywhere from six to 10 times the strength of your traditional roofing felt. To demonstrate this. As you can see, I cannot tear this in half versus very, very easy. And I promise I'm actually trying. And I'm not just weak so this is a massive, massive upgrade over your traditional roofing felt. The other big benefit of this is humidity and heat. This will handle humidity and heat far better than your asphalt based underlayments, which will dry up in heat or absorb water. So this is a big upgrade from the roofing felt. And that is the reason that here at Reimagine Roofing, we don't even offer the felt because the synthetic is such a major upgrade and such an important part of the roofing system. Now, the next type of underlayment we want to talk about is what's called ice and water. So ice and water is a peel and stick underlayment, which means that it has an adhesive backing. And traditionally how this is used, even if you go with a base model package. One second, let me get this off to show you guys. All right. Even with the base model package, your ice and water is going to go in areas that are most likely to leak. So on a traditional home, this is going to be valleys and eaves. So a valley is anywhere where the roof comes together and all the water is directed there and then eve is the edge of the roof. So on all of the projects that we do use, even if you're going to go with the synthetic underlayment, you will get a ice and water reinforcement in the valleys and the eaves. This is something that we do as a mandatory upgrade free of charge, because we understand how valuable it is to have ice and water in the valleys. Now, the reason this is so valuable is, as you can see, this is a giant sticker. So it just, instead of being held on by nails, it goes straight to the decking right there and provides an additional layer of protection. The other really nice thing about your peel and stick ice and water is that if a nail does go through there, when this heats up, it reseals around the nail and it provides that reinforcement in your most vulnerable areas. Now, a very common upgrade and a very popular upgrade is to go from the synthetic on the entire roof. Synthetic is it's held on by cap nails. In fact, you can see right here on another sample of a synthetic underlayment is held on the decking. What that means is to install this piece of synthetic on the entire roof. I'm looking at putting anywhere from 5 to 10,000 nails on that roof. That's in addition to the nails that, that I'm going to need to use to install the shingles or any other type of roofing, such as metal roofing with screws. Why that is so important is going from 5 to 10,000 nails to no nails, that is 5 to 10,000 potential leak points that are no longer existing. In addition to that, this will also reseal around the nails that are going to be used to install the shingles. Now step up from there. And the top line currently in underlayment technology is what's called high temp ice and water. So this is high temperature ice and water. Now these are classes of underlayment, which is important to understand. There's a ton of different brands. It's like if I set a pickup truck and you might think of a F150 or a Chevy Silverado, but a pickup truck is a, is a type of truck and then you have different brands. Same thing as what we were talking about here. High temp self adhered underlayment is a type of underlayment and there's many brands out there that are high quality. What's more important is to understand the types of underlayments less so than the brands. So what makes a high temp self adhered underlayment different than your standard ice and water? Well, it's in the name high temp. High temp underlayments have a temperature rating of up to 240 degrees Fahrenheit, a thermal stability of up to 240 degrees, which sounds like a lot, but if you've ever been on a roof in the middle of summer and you put your, your hand on there, or you put a temperature gun on there, there's many times that roofs are getting up to 150, 160, 180 degrees. Especially if you're under metal or you're in a direct sunlight at the peak of the day. So this high temp self adhered underlayment is specifically designed for high wind areas as well as high temperature areas. And the reason for that is because what happens and this is also installed the same way. Take it off, slap it on there like so. And the reason it, it's so superior for the high wind area as well is because how this works is it's one giant sticker. So when you install something with nails, if you put a nail here and a nail here, this area in between there becomes a weak point. And so when the shingles get ripped off by a windstorm and your underlayment is the only thing exposed, that area, the wind will get under and it will pull it up and then it rips off your entire underlayment. With this, there are no weak points. This entire aspect is adhered. And once it Heats up in the sun and gets adhered onto that plywood, it is not coming off even during hurricanes, even during high windstorms, monsoons, etc. Doesn't matter the wind event, this will stay on that decking. Additionally, it is also reinforced with higher tensile strength than your standard tar paper. And it's much thicker and much stronger than your standard synthetic as well. And so that means it is much more resistant to hail strike. So when that shingle gets damaged, again, that high temp self adhered underlayment will resist that damage and it will not allow water to penetrate into the home. And the final aspect, just like your ice and water, that high temp self adhered underlayment will reseal along all of those nails that are going to be input into the the roof decking. So in summary, you have four basic classes of underlayment. You have your older outdated technology that many roofers still use. Roofing felt, 15 pound felt, 30 pound felt roofing tar paper. Tar paper, those are all the names for it, but it's all basically the same thing. You know, I would call it a little bit thin, thicker construction paper, but this is basically construction paper. And again, this is your last line of defense. So if you want to trust your home with construction paper, it is something that we will not do here at Reimagine Roofing because we do not feel like that is the best solution for your home. Next step from there is our synthetic, which I'm trying to rip this one more time just to show you guys, but again, this is a different brand of the synthetic that I tried to rip earlier. But as you can see, doesn't matter the brand. All of them have a very similar consistency and this is a mechanically fastened product, meaning again that we will be putting the roof on with cap nails, which then leaves potential weakness areas down the road. All right, next from there is your ice and water, non high temp, just your standard granulated ice water. This is a peel and stick. This is used in your most vulnerable areas, your valleys and your eaves. And again, this is a standard upgrade that we pair with our synthetic for those vulnerable areas.