How to Insulate the Rim Joists with Foam Board insulation & Why you should

Hey what's up everybody this is CLS all-in-one. Today I'm going to show you how to insulate the rim joists on your house using foam board insulation. Insulating the rim joists can help save you money for heating and cooling costs and it's fairly cheap and simple to do. So right here we're looking at the interior location of my rim joist that I will be insulating with foam board insulation. This is located in my basement but if you have just a crawl space you should have some sort of rim joist that does look similar. The rim joist is located on top of the sill plate and right here you can see the rim board being attached to the floor joist. The rim joists are also commonly called rim boards or headers. Here is a picture of the outside of my house with the exterior finished and this shows where the rim joists are located. A lot of times these areas are either insulated incorrect or have no insulation at all which can really affect your heating and cooling. In the cold months the hot air can escape while letting the cold air in and in the warm months it becomes the opposite. Quite often you'll see these areas insulated with fiberglass insulation but unfortunately this type of insulation does not work well. It does not provide a good vapor or moisture barrier which can lead to mildew or mold damage. When the outside temperatures mix with controlled temperatures inside your home it can cause condensation without a proper insulated moisture barrier and this is why foam board insulation works well because it provides insulation with a moisture barrier at the same time. Now there are multiple types of foam board insulation such as Artec polystyrene and Owens Foamular XPS and I would recommend using at least inch and a half thick foam board or thicker. The Owens foam board is a little easier to work with and has an R value of 7.5 at an inch and a half thick but it does lose 10% of that R value over time. The Artec foam board makes a little bit of a mess when cutting it and it has an R value of 6 at an inch and a half thick but it does retain all of its R value over the life of the product. And this is the product I will be using today but either one of these products will work just fine. So to start off with here I'm going to get the measurements in between my floor joists where the rim joist is located and get the exact width and height. And more than likely the dimensions are going to vary just a little bit in between the different floor joists. So just go ahead and keep a notebook with you that way you can write down all your measurements as you're going. And I like to make my cuts about 1 16th of an inch smaller both directions just to ensure I can wedge the insulation in place and it's not too tight. To make the cuts it's very simple just mark with a pencil then use a straight edge along with a utility knife to score the foam board approximately three quarters of an inch deep. Now go ahead and hold that foam board in place and hit the back side of the foam board with your hand until it breaks in half. And once it does break in half go ahead and grab your utility knife and make a cut on the back side where it just broke to finish that cut. So luckily for me I did have a bunch of my measurements that were very close to each other so I was able to cut just one piece and use that as a template to cut multiple pieces. And more than likely the height should be the same for all your pieces but the width will probably vary. And it would probably be a good idea to test fit the first piece before cutting multiples to ensure that your measurements are good. So I have multiple pieces cut now and it's time to go ahead and wedge these up in place against the rim joist. So I've got one there in place and now I'm put my second one up and these should be a fairly close fit. You don't want these too loose. You want these to be able to kind of stay in place. Now I'm going to grab a can of Great Stuff foam insulation and this is the window and door formula. And what's nice about this formula is it doesn't expand too much and make a huge mess. There are some other kinds out there that expand a lot more and make a lot bigger mess. So here's a look at one I've already done and here's one that needs to be done. So I'm going to grab my can of spray foam insulation and go around the entire perimeter of the foam board insulation. Now you don't have to get carried away and use a bunch of this spray foam insulation. You just got to make sure you use enough to fill in the gaps and make sure that you have a seal all the way around the perimeter of the foam board insulation. And don't worry if it doesn't look pretty. This stuff is pretty hard to work with and it usually does not look very attractive. The purpose of the spray foam is to that you have a nice and strong seal for your moisture barrier foam board insulation. So I now have my entire front rim joist insulated with the foam board insulation along with the spray foam sealant around the edges. Now it's time to do my side rim joist as well. And it's the same routine here except I just have to cut longer four foot pieces then use the foam sealant to glue these seams together. Okay it's time for me to get out of here but if you do like this video if you could hit that like button and have yourself a great day and I'll see you next time. Thanks for watching this is CLSO1. If you want to hear more from me please like and subscribe. And to see more of my videos just click any of these categories to see more.