![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgP-tN1TT3Is6kmbKMIAwXUdKFuuZJR4CC9QUUJN5eKaVnPTzupMqrJRzh-vqiF2BahN2MjaZnOcB0GqF_bPZCr8AKsky3GR3G8rn3AWtyV1DxVQBC4X0QqDmvME6-B9OcW1Y6BrSfY/s320/IMG_0002.jpg)
Traditional construction around East TN uses OSB (Oriented Strand Boasd - basically, particle board) sheathing and an overlay vapor barrier of Tyvek house wrap. You've all seen these houses. They look like a house wrapped in white paper until the outside siding is later added. (One house being built near our rental still has only the Tyvek house wrap after over a year... I'm guessing they ran out of money when the wheels came of our economy). Tyvek makes a good vapor barrier and has been a staple of the building industry for years. Our specification for this house even calls for a conventional house wrap. Rick Hessick of BR2, our builder, suggested we look at SIS and with my new-found appreciation for styrofoam, we looked closely. It's a great idea! SIS replaces the OSB, and the tyvek. PLUS, it's got a better vapor barrier performance
because it can be sealed better AND it's got the insulating properties of 1/2" of styrofoam. Since we already planned to use foam for our insulation system, this product just adds to the R-value in our wall system. To top it off.... it's a real pretty blue :)