Different Types of Underlayment and How To Apply Them To Your Shingle Roof

[Music] foreign [Music] so once you've got your roof torn off and the decking's inspected and you've repaired anything that you need to repair it's time to start installing your roof system but before you install your shingles the first step is to apply an underlayment like this asphalt roofing felt in this section I'll be discussing why underlayments are important I'll show you a variety of different products and how to install them [Music] I consider a quality underlayment in a central part of a quality shingle insulation the underlayment serves several important functions in the Roof System first it provides a primary layer of protection to the roof decking and the building below it in the event it rains before you get the shingles on so you've got your roof torn off and you're going to put your felt paper down maybe it rains maybe you come back the next day it's going to be first layer of Defense in new construction applications obviously this is of course going to be especially important because there were never any shingles or old roof on to begin with even if you're not worried about it raining in to your structure the underlayment will keep your decking material dry and prevent it from warping or swelling during the construction process most importantly the underlayment is a secondary layer of protection against wind driven rain or snow and ice that may get under some of the shingles in the event of a minor leak the underlayment is going to provide an important layer of protection think of it as a second roof under the shingles in a minute I'll show you where to use underlayments in particularly vulnerable areas to prevent damage and leaks from ice and snow underlayments also provide an important separation layer between the decking and the shingles in some cases wood pitch resins found in the decking can leach into and damage the underside of the shingles hey everybody thank you so much for watching this video please hit subscribe so you can be a part of my channel you can watch all my videos that cover complete stages of both shingle and metal roofing tons more content coming out soon about all aspects of roofing including skylights and trim and sheds and whatever you're interested in there are a variety of different underlayment products out there and I'd like to explain briefly just a little bit about each type there are three main categories of products out there and they all serve different needs first you've got your typical asphalt Felts also called tar paper these are the most common and inexpensive underlayments and are referred to as water resistance because while they do shed most water they also absorb some amount of water there are two main types of felt paper that you're going to find out there 15 pound and 30 pound felt you basically these products are the same but the 30 pound felt as the name implies is twice as thick with more asphalt per square foot which makes it far stiffer than the 15 pound variety both products generally cost the same price per roll but the 15 pound roll covers twice as much area as the 30 pound roll you're going to get 400 square feet or four squares out of the 15 pound roll and 200 square feet or two squares out of the 30 pound roll for the most part here in the South we've we go with the 15 pound felt and it works fine and I and I could recommend that both types both the 15 and the 30 pound Felts serve the same purpose and there aren't too many times where I found that a thicker felt is going to help you out too much differently than the the 15 pound Felts one area that the 30 pound felt does do better is when you're going to leave the paper on for a while exposed to the elements or there's going to be a good bit of foot traffic on the roof before you install the shingles the 30-pound felt just holds up a lot better in both of these conditions because it's thicker and also tends to lay flatter when you roll it out on the deck as well as a more durable product I wouldn't discourage you from using it particularly on steeper roofs where traction is more important the 30 pound felt is also far less likely to tear underfoot which is definitely a safety issue however in all these circumstances I've just mentioned a synthetic underlayment is going to be an even better choice for basically the same price or a little cheaper than the 30 pound felt and I'd recommend going with the synthetics we'll talk about that in a second it's up to you which type to use but I will say that nearly all of my work and the last decade has been with 15 pound felt and the 15 belt felt has really served me well the next category of entertainments we're going to talk about are known as waterproof underlayments and like I said the typical organic asphalt Felts 15 and 30 pound Felts do tend to absorb a little bit of moisture these products are completely waterproof and are used in areas that need Extra Protection while there are a variety of brand names for these products such as weather watch and Winter Guard I commonly refer to these products as ice and water Shield which is a brand name typically these products come in a roll that is three feet wide by 65 feet long which gives you right at 200 square feet of coverage or two squares per roll so you're going to need to know that when you're ordering your materials as you can tell this is a completely different product than asphalt felt papers it's much thicker and it comes with a self-adhering sticky back so it's basically got a adhesive on the back that will stick when you peel this release paper off so it has a granular surface on it that's similar to the surface of shingles the sticky back under the paper allows it to glue directly to clean decking surface so it typically doesn't require nails to install because of its construction these products are designed to seal around Nails driven through them and it therefore provides a much better protection against leaks than traditional Felts do so it's got kind of a thicker sticky asphalt component in here that when you drive a nail through it it kind of glues up around that nail and prevents any water from going going through that so due to the fact that it is designed not to absorb moisture it will never wrinkle up like Felts do when they get wet and so it lays flat leaving you with a better finished appearance underneath it ice and water Shield is a great product I know some roofers who do a lot of entire roofs that are covered in this product instead of traditional asphalt Felts so the third category of underlayments that we're going to discuss are called synthetic underlayments these are all more recently developed products and I'm not completely sold on them in general because there are a lot of different ones out there a lot of them are new and you never really know what kind of Quality quality you're going to get with a new product however as the price of asphalt products go up these materials are starting to look a little bit better in comparison it's hard to make a generalization about synthetic underlayments as there are tons of different types out there as you can see they have kind of a plasticky feel and I'd compare many of them to house wrap materials like Tyvek if you're familiar with that I've got two different brands here they're both a little bit a little bit different but um same same general principle and these are both rather thick heavy duty synthetic underlayments they do make thinner ones that are more comparable to 15 pound felt in their thickness if you're interested in going with these products for some of the reasons I'm going to discuss in a second I'd be careful which ones you choose and talk to the supplier about which brands they've worked with the longest to make sure that you're getting a high quality product as with any new material there have been some products that came out and didn't really turn out to be as high quality as they we suspected they were so in general these roles can serve the exact same purposes traditional 15 and 30 pound Felts not they're not the same as ice and water Shields but they have a few characteristics that make them stand out for one thing they're fall far more durable to tearing compared to felt paper and stun even have an added sort of sticky element in the surface or this one's got a this woven strand in it that make them particularly easy to walk on on steep roofs so this this weave in here makes it makes a very good amount of friction when you're standing on it which is a big advantage due to the fact that they don't absorb any moisture like your asphalt Felts do they lay very flat and they don't wrinkle as much as felt also and this is important they're generally rated to stand up to exposure to sunlight far longer than asphalt Felts as a result if you're going to leave this on your building for a while before getting the shingles on like in a new construction situation where you dry it in and then you're finishing something else you'll definitely want to use a product like this as felt papers tend to wrinkle and go bad after even a week or two or heavy rain or two on 15 pound felt to make it wrinkle up really bad and you really don't want to lay shingles over felt that's been exposed to the weather for very long so new construction or tear-offs that are going to sit there for a little while oh the synthetic Felts are are worth their weight for sure so most of the synthetic Felts are also far lighter than asphalt felt and that's nice if you have to carry a bunch of these rolls up the ladder synthetic Felts are generally not always but generally sold in 10 square rolls so you also have to carry up far for fewer rolls than felt which are two and four square to the to the roll and that's going to help you speed up your installation a little bit too so the synthetic underlayments are a good choice when one the felt will be exposed to elements for more than a few weeks or on a steep roof where you appreciate the tear resistance and improved walkability of some of the products and that's generally when when we use the synthetics is in those two circumstances as we look at installing underlayments I'm going to start with the ice and water Shield as this is going to go on first before I go into the different locations for this product I'm going to try and explain one of the main problems we're trying to solve by installing ice and water Shield ice damming is a phenomenon that occurs in areas on your roof where the warm insulated areas of your roof meet the cold uninsulated areas of your roof edges now this problem typically only occurs when you have snow and ice on the roof or an extended period of time here in North Georgia where I work we do occasionally see some snow and ice but it generally doesn't stick around very long enough to cause problems in more than a decade of work I've never seen an eye stamp cause a leak here so we generally don't install protection against it however if you're in an area of the country that sees regular snow you simply must use this sort of protection against ice dams even if it only happens once every 10 years an ice dam leak can pour significant amounts of water into your home and there's really little you can do to stop that leak until it either warms up or it gets much colder and the water freezes again so back to why ice dams form in the case of your home the areas above your attic are going to stay warmer than the areas around the perimeter of your roof that are basically outside your house and they're going to be more or less the same temperature as the outside air as the warm air above your attic Works to melt some of the snow on your roof that water runs down to the outside edge of your roof where it is much colder okay so the water is moving down here and once it hits this Zone it's much colder than the roof area up here and it's going to begin to re-freeze as we know when water freezes it expands that works to force the water back uphill around the edges of the shingles where it normally wouldn't go if it was just flowing down the roof in a normal rain now you've got this ice lodged up under your shingles and when it does begin to warm up outside that water is going to melt and leak down into your house in the soffit area I want to add at this point that you can work to avoid ice dams by improving the insulation in your attic and making sure you have proper ventilation which I cover in a separate section both the both of these steps the insulation and the ventilation are going to keep your attic cooler and help the premature thawing of the snow on the on the main part of the roof that causes ice dams if you look at your roof in the winter it should have an even layer of snow across both sides of the roof and not just be covered in snow around the edges this even layer of snow is an indication that you have good ventilation and adequate attic insulation so now that you understand ice dams I'm going to explain how to prevent them with ice and water Shields you want to apply this product all the way around the perimeter of the house at the lower parts of the eaves it's not a bad idea to run it up the vertical Gable ends but most aiming ice damming occurs around the lower Edge where the water runs as it melts so I've got this area Illustrated here starting from the outside of the house to three feet up the roof approximately and this is the area that's really vulnerable to the ice refreezing and working its back it's way back up underneath the shingles all right now we've got the drift Edge on we're ready to install our underlayment first thing you want to make sure when where you're putting your ice and water seal down is that the deck is clean and free of the debris this is a self-adhered product and so if you try to glue it down to a dirty deck or over old shingles or felt paper or something like that it's not going to stick very well so this is easy because this is our model is new but uh get everything clean tidied up all the nails off and stuff like that so you'll notice that uh on the back of the Roll it's got this two pieces of release paper so let me hold this here so it's split down the middle here and this is going to come in handy when you're laying it out so first thing you want to do is roll your felt out and cut it to length if you've got uh a really long run it might help be helpful to do several short pieces for example here on the model I've just just cut a piece long enough to go up to the Dormer here and we can piece in the other the other sections so just make sure that you've got it cut a little bit too long and you can always trim it off later so make sure that you leave enough to overlap the edges six inches if you're going to piece it in once you've got the piece laid in place and it's run straight with the edges of the roof here on the side again you can cut a little bit off later you're ready to stick it down there's a couple different ways you can do this but I found the easiest way to do it is what we call the peel and flop method that involves taking the backing off of half of the sheet at a time so if you're working alone and the piece wants to slip you know this Roots pretty pretty steep you might put a little nail or staple or something in it to hold part of it in place while you're doing it so so we've got it started here we're going to roll this piece roll this piece down and pull the pull the release paper off foreign like that and then stick it down now don't worry the the this paper is not extremely sticky which helps you if you need to move it around or pick it back up it's really heat activated so it's not going to be terribly sticky when you start but as you can see now that we've got this laid down it's sticky enough to hold to it to get started and as you walk on it as it heats up in the sun it's going to stick down a lot better so again you can put a couple Nails in it if you're worried about it coming up so um if it's very cold out especially you might put a few Nails in it to hold it in place so once we got the top part down we go ahead and lick and pull this bottom part off and there we go as you can see it's this real nice heavy heavy weight product that lays really flat really easily and it's going to stick down if you have any places that you need to uh you're worried about it sticking you know you can press it down or walk on it or whatever but like I said once it gets nice and warm and you nail all the shingles on it's going to stick really well in regards to the ice and water shield and also the felt that we're about to put on these products are not rated to be exposed to sunlight so you should never use these products in areas that aren't going to be later covered with another roofing material such as flashing uh with a valley or with felt paper it needs to be covered with shingles when it's done later if you want to leave something like that open there are similar products like this that are useful in these areas that are rated to be exposed to the elements if you leave this stuff sitting out in the sun for too long it's going to wear out really quickly so um now we we talked about eye stamping we've got the ice and water Shield applied down here at the eaves to protect against that we also want to use the ice and water shield around any penetration such as this Dormer the pipes we're going to show you later how to do that we want to run the the ice and water Shield membrane up the side around the Dormers we also got it in The Valleys here if you've got skylights you're definitely going to want it there to run it there it's really just back up that's going to go around anything that's leak prone so anything coming out of your roof you're definitely going to want to apply this around it also in the valley so keep in mind too that the model we're working with here is a little smaller obviously than your average roof this looks a little different than it would on your roof this is a 36 inch wide piece of of membrane in a regular Valley would look you know a little smaller all right so now that we've got all the ice and water Shield installed everywhere we want around the penetrations we're ready to install the rest of the underlayments again in this video we're going to be using this 30 pound felt and you can just roll the felt out starting at the bottom of the roof low the low point and making sure that it laps at least two inches over the lower course and six inches on the side so what's really nice about this ice and water shield and the felt as well is that there's this line here and this is a little this is probably six inches it's probably a little bit more than you need to but this will give you a good guide as far as uh how far down you want to cover over it so when you're applying the felt I like to use these sort of plastic cap nails I have the one inch long variety work fine you can also use Staples in a hammer attacker like this this is maybe a little quicker and a lot of a lot of our guys like to use the hammer attacker they move really quick but keep in mind that the felt paper is not going to be held down nearly as well with as it would be with staples if you're using this so the hammer attacker probably for you is going to be a good way to get it started hold it in place and then come back with the plastic cap nails and uh and nail secure it down with that so these nails are also going to be essential if you're going to leave the underlayment on for any length of time the Staples only going to hold it on very short period of time if you're going to have to come back a couple days or a week later definitely want to use the plastic cap nails manufacturer guidelines calls for using a nail every six inches in the lap and two staggered rows one foot apart in the field so I'll note too that many of the synthetic underlayments will have marks that are already printed on them where where you're supposed to put the nails so uh we're going to go ahead and install the underlayment now one thing that I want you to make sure of and we'll cover these sort of details a little more in the section on uh running your shingles in The Valleys but you never want to put any Nails close to the center of the valley so out here is fine over here is fine but you always want to keep your nails or Staples very far away from the middle of the valley so in this case we're just going to run the felt over to right in here because we've already got the belly covered with the ice and water Shield [Music] we got everything nailed down and I just want to make the point that uh if you've got if you're going to venture Ridge and you've got that cut open already I recommend go ahead and roll and felt over the top and closing up the closing up the ridge temporarily that way just if it rains or anything like that or any debris will will be kept from getting in there and then you can just come back and cut it open real easily right before you put your ridge vent on later and that about does it for underlayments we're going to move on to the next section and show you about starter shingles [Music] if you'd like the complete series for yourself on how to do shingle or metal roofing you can go to my website roofingintelligence.com and there you can get a membership to either stream or you can get a DVD in the mail it'll show you how to do all the steps for either of those types of roofing enjoy this video thanks so much for watching

Channel: RoofingIntelligence.com

Views: 36,105

Keywords: roofing, asphalt roofing, how too, how to install roofing, how to install shingles, installing shingles, roof repair, roof replacement, how to install a new roof, diy roofing, roof shingles, roofing shingles, three tab shingles, architectural shingles, roofing instruction, shingle installation, roofing a house, roofing a shed

Id: vuhD2aeI1_E

Length: 21min 11sec (1271 seconds)

Published: Tue Mar 21 2023