What a coincidence that just yesterday I commented in an earlier post about the effectiveness of tar paper as a house wrap, and today I look in the February issue of The Journal of Light Construction to see new tests confirm that good ol' 15# asphalt felt outperformed all other housewraps in tests by the Building Materials Technology Program at UMass. ONLY aspahlt felt left the samples of plywood completely dry after exposure to saturating water in the lab tests. To quote Paul Fisette of UMass, "Why not choose the product that doesn't leak water? It is inexpensive and forgiving. Felt is dynamic. If water gets on the wrong side of a felt wrapped wall, the felt can absorb the water and over time allow drying to the outside of the building." My personal opinion is felt is a great product, but if you don't plan to install siding immediately, Tyvek installed with "cap nails" will provide an effective weather barrier and still be there after the wind blows.