There are a few components to vinyl siding, but perhaps the most important for added efficiency is the air and water barrier. For years if an underlayment was even used, many contractors used felt paper as an air and water barrier for siding projects. Tyvek became a popular choice as well, and has remained so today. We recommend a better system- the RainDrop 3D building wrap by GreenGuard.
Permeability is a very important factor when adding a product like this to your home. As I mentioned, you probably have either no air/water barrier, or perhaps felt paper on your home currently. Adding an air/water barrier will help make your home much more efficient if you consider that alot of the air infiltrating and escaping your home is doing so through the walls. The air/water barrier will help that considerably. But if water does get past the barrier, the permeability is important to ensure the water can escape and not cause rot and mold issues in your home.
Tyvek performs alot like the Gore-Tex found in your outdoor gear- and for good reason, they’re both manufactured by DuPont and have pretty similar makeup. Both are uniquely engineered products made by spinning extremely fine high-density polyethylene (HPDE) fibers that are fused together to form a strong, uniform web. This allows the product to prevent larger water droplets from penetrating, while allowing smaller water droplets (vapor) to escape. However, when you look at how well the product does at allowing the vapor to escape (permeate) you’ll find that Tyvek might not be the best solution. This has led some homeowners to find rot and mold in areas they thought were protected by their air/water barrier.
RainDrop 3D was the first building wrap to add innovative draining channels to aid in the direction of water flow. The increased channel depth today allows it to manage moisture better than any other wrap on the market. GreenGuard RainDrop 3D improves the energy efficiency of buildings through more effective air and moisture management. In fact, when compared to Tyvek, GreenGuard Raindrop 3D drains more water at every simulated rainfall intensity- and 50% more water when subjected to a 2″ water head test simulating heavy rainfall.