The ptc@home Continuous Exterior Insulation Detail

In the video series, ptc@home, Editor Dan Morrison (me) replaces the siding on his 1950s cape-style house. Because replacing the siding is a once-in-a-generation opportunity to improve the insulation in an old house SERIOUSLY, Dan (I) also added two inches of continuous exterior insulation—Styrofoam, in this case—to the outside of the walls. I added Tyvek, sealed at window and door openings, as part of the air barrier system before adding two layers of Styrofoam, over which I added new TruExterior siding. The continuous insulation retrofit process - I removed the clapboard siding to reveal 1x6 T&G sheathing. The windows had been replaced from the inside and the original 1957 brick molding was intact. - Removing it revealed a lucky break. 1x3 sub casing circumscribed the window and acted as the window stops for the tilt-in replacement windows installed recently. - They also provide a continuous surface for flashing tape to seal off that window opening. - I cut off the sill flush with the wall sheathing and sealed the sides and top with DuPont flashing tape. - At the bottom, I installed a wide strip of [Flexi flash] tight to the replacement window and leaving the release sheet on the outer section. - Now I installed Tyvek over the wall, cutting out at the windows. - Sealing the edges to the flashing tape that seals the 1x3s around the opening. - In this assembly, the Tyvek is really mostly for air control. The outer face of the Styrofoam will shed any water that gets behind the siding. - Now the foam goes on. - And the sill flashing tape can be folded down and stuck to the fact of the styrofoam. - At the bottom of the wall is site-bent coil stock to keep the bugs out. The whole thing is covered with a rainscreen product called DrainVent. - Finally, I added new exterior trim and siding from TrueExterior. The result has been about a 40% drop in energy use and a lot fewer free weekends. More videos about continuous exterior insulation: - ptc@home: Exterior Insulation Retrofit and Siding Replacement - Outie Window Installation: Weave It Into The Exterior Foam - Innie Window Installation, Exterior Foam Insulation Retrofit - Building America Solutions Center: Continuous Rigid Insulation Sheathing