The Importance of Insulation and Vapor Barriers in Attics

When it comes to insulating your attic, it's essential to understand the importance of insulation and vapor barriers. As the video explains, once you've finished with the walls, it's a good idea to head up to the attic and fill those rafter bays. This can be done by using a hose to fill the space, much like we see in the example provided.

Insulation is rated by an R value, which measures its resistance to heat movement. The bigger the number, the more insulation you have, and the better it performs. In this case, we have r19 insulation, which is sufficient for most attics. However, if you want to increase the efficiency of your attic, it's recommended to buy a 12-inch thick piece of insulation and lay it on top of existing insulation.

When using insulation, it's crucial to understand how it interacts with the vapor barrier. A vapor barrier always goes to the warm side, meaning that if you heat your house most of the time, the vapor barrier will face downwards towards the conditioned space. If you air condition your house most of the time, the vapor barrier will face upwards towards the hot sun.

The reason we use a vapor barrier is for condensation. Warm air has moisture in it, which gravitates to the cold and condenses. This can lead to condensation getting into the insulation, wetting it, and lessening its effectiveness. It can also cause condensation on the underside of your roof sheathing, leading to rot, mold, or mildew.

Paper is not a proper vapor barrier, despite being around for a long time. Instead, we can use polyethylene vapor barriers, which are common today. However, when laying down insulation and a vapor barrier, it's essential to understand where they meet. If the vapor barrier is not installed correctly, moist air can pass through, leading to problems.

To ensure optimal performance, it's crucial to lay down insulation perpendicular to the ceiling joists. This allows for good airflow and helps to cover up any seams or gaps. By continually packing the insulation tightly against the underside of the roof rafters, you can create a comfortable and energy-efficient space.

When installing insulation, it's also essential to consider ventilation. If you put too much insulation in place, it can become compressed, reducing its effectiveness. Ventilation is critical for most roofs, as it allows air to circulate and prevent moisture buildup. By packing the insulation tightly but not too tightly, you can create a balanced and efficient system.

In conclusion, understanding insulation and vapor barriers is crucial for creating an energy-efficient and comfortable attic space. By choosing the right type of insulation, installing it correctly, and considering ventilation, you can ensure that your attic performs well and lasts for years to come.

"WEBVTTKind: captionsLanguage: enso when you're done with the walls it's probably a good idea to go up to the attic and fill those rafter Bays because you can just take that hose and fill it all in much like we have here some ceiling or floor Joys pump it in and fill it up mhm you can fill it up to 6 in you can fill it up to 2 feet over time it will compact or settle down gotcha or you could use pink fiberglass batting like we've got here and when you use it make sure that you uh put some gloves on and of course a dusk mask when you do the installation right now I've got this in my attic I put it in myself and it is a simple homeowner job it's a great weekend project but here I noticed that youve got a paper backing on this mhm that's for a vapor barrier all right explain the whole Vapor Barrier thing VAP all right a vapor barrier always goes to the warm side so if you heat your house most of the time the vapor barrier faces in down to the condition space right if you air condition your house most of the time the vapor barrier faces is up or out to the hot sun that's beaten down on the roof exactly all right so now the reason we use a vapor barrier is for condensation right right warm air by Nature has moisture in it as it gravitates to the cold there it condenses right that's not a good thing it's not a good thing because the condensation can get into the insulation wetting it lessening the effect of it could also condensate on the underside of your roof sheathing causing rot mold or M but since when is paper a proper Vapor Barrier it's been around for a long time you can also have a polyethylene Vapor Barrier right here which is pretty common today unfaced insulation all right so talk to me about I I guess what we would call the strength of the insulation the strength of the R value insulation is rated by an R value 6 Ines of insulation which we have right here is called r19 all right the bigger the number the more insulation we have the better and R is the resistance to heat movement exactly okay so is r19 sufficient for an attic not for any attic I would recommend increase the efficiency of that Attic by simply going to your home center and buying a 12in thick piece of insulation big piece right here and then what just laying it on top lay it on top but first of all I want you to see something when I lay this on top and I turn this over what do you see uh a vapor barrier a paper one but a vapor barrier right now where is that Vapor Barrier that VAP between this batting and above this one and that's where it's not supposed to be because any moist air that should migrate through the vapor barrier below will collect on this wetting this all right so can we just peel it off peel it off and give unfaced or you can buy it unfaced all right now you laid it sort of perpendicular just by coincidence or do you do that on purpose it it's actually more efficient think of the insulation where it meets your ceiling joist there's a slight crack that air can migrate up through here right ah all right so now if you lay perpendicular you're actually covering up those seams right and I'm also insulating the ceiling joist right cuz he can transfer through those all right now imagine that these are the roof rackers yep setting up to the roof right now you simply take your insulation and you push it in tight to the underside of the roof Raptor but not tight enough so that it hits the underside of your plywood sheathing why not we haven't doubled up here well you want the air to get up into here if you put too much insulation in here it's compacted it's not as efficient right and ventilation is critical for most roofs right so just continually pack your insulation nice and tight against and go all the way across your attic nice blanketso when you're done with the walls it's probably a good idea to go up to the attic and fill those rafter Bays because you can just take that hose and fill it all in much like we have here some ceiling or floor Joys pump it in and fill it up mhm you can fill it up to 6 in you can fill it up to 2 feet over time it will compact or settle down gotcha or you could use pink fiberglass batting like we've got here and when you use it make sure that you uh put some gloves on and of course a dusk mask when you do the installation right now I've got this in my attic I put it in myself and it is a simple homeowner job it's a great weekend project but here I noticed that youve got a paper backing on this mhm that's for a vapor barrier all right explain the whole Vapor Barrier thing VAP all right a vapor barrier always goes to the warm side so if you heat your house most of the time the vapor barrier faces in down to the condition space right if you air condition your house most of the time the vapor barrier faces is up or out to the hot sun that's beaten down on the roof exactly all right so now the reason we use a vapor barrier is for condensation right right warm air by Nature has moisture in it as it gravitates to the cold there it condenses right that's not a good thing it's not a good thing because the condensation can get into the insulation wetting it lessening the effect of it could also condensate on the underside of your roof sheathing causing rot mold or M but since when is paper a proper Vapor Barrier it's been around for a long time you can also have a polyethylene Vapor Barrier right here which is pretty common today unfaced insulation all right so talk to me about I I guess what we would call the strength of the insulation the strength of the R value insulation is rated by an R value 6 Ines of insulation which we have right here is called r19 all right the bigger the number the more insulation we have the better and R is the resistance to heat movement exactly okay so is r19 sufficient for an attic not for any attic I would recommend increase the efficiency of that Attic by simply going to your home center and buying a 12in thick piece of insulation big piece right here and then what just laying it on top lay it on top but first of all I want you to see something when I lay this on top and I turn this over what do you see uh a vapor barrier a paper one but a vapor barrier right now where is that Vapor Barrier that VAP between this batting and above this one and that's where it's not supposed to be because any moist air that should migrate through the vapor barrier below will collect on this wetting this all right so can we just peel it off peel it off and give unfaced or you can buy it unfaced all right now you laid it sort of perpendicular just by coincidence or do you do that on purpose it it's actually more efficient think of the insulation where it meets your ceiling joist there's a slight crack that air can migrate up through here right ah all right so now if you lay perpendicular you're actually covering up those seams right and I'm also insulating the ceiling joist right cuz he can transfer through those all right now imagine that these are the roof rackers yep setting up to the roof right now you simply take your insulation and you push it in tight to the underside of the roof Raptor but not tight enough so that it hits the underside of your plywood sheathing why not we haven't doubled up here well you want the air to get up into here if you put too much insulation in here it's compacted it's not as efficient right and ventilation is critical for most roofs right so just continually pack your insulation nice and tight against and go all the way across your attic nice blanket\n"