When I last left off discussion of the sill repair project, I was carving away at the house with a chainsaw (see Heavy Duty Wood). Well the carving went on to include shaping the replacement beam and after carefully measuring and sketching out the cuts I needed to make, I was able to shape it to fit snugly in place where I had taken out the old rotten one. After all the sweat and worry that went with removing the rotted sill and fashioning a replacement, the sight of the new-old beam in place was decidedly satisfying.
The next task was sealing up all the cracks with spray foam insulation, and then replacing the sheathing that had been removed to access the rotted sill.
Sealing the cracks with foam was pretty straight-forward. I've done this enough now to know how to keep it neat. The poly-urethane foam sticks to everything it comes into contact with and if you're not careful you'll be discovering it in all kinds of unintended places.
Replacing the sheathing took a little more thought than you might expect. The original sheathing is made up of rough sawn 1-inch boards. The original clapboards are about a half inch at their thickest and are nailed directly to the 1-inch boards. So the gap I had to fill between the studs and the surface I would be remounting the cement shingles to was between 1-1/2 to 1-3/4 inches. The nature of the original sheathing and the uneven hand-hewn foundation sill didn't provide for exact measures. After considering a couple different options for replacing the sheathing and building up the surface, I decided on using one layer of 1/2" plywood and then a layer of 1" rough sawn boards I had salvaged from demolition work almost three years ago. This saved me a little money and helped make some space in the shed. (The pink strip that you see in the picture is a sill plate foam strip that I used in an unconventional way to help prevent air infiltration through the gaps created by the uneven sill beam.)
Once the sheathing was back in place, I was ready to install some water-proofing. I used Vycor self-adhesive vinyl flashing to protect the bottom edge of the new sheathing. The weather report said rain was on the way, so I made sure to get all the vinyl flashing in place before I quit for the day. However, the next morning when I went out to get the newspaper, I noticed that the strong wind of the night before had pulled the Vycor from the house. Unfortunately it hadn't adhered well to the rough sawn sheathing boards. I was able to salvage half of it and got it re-applied--this time with staples. Stapling is not the preferred way of mounting this product but it was the only way I was going to get it to stay in place under the circumstances. Luckily the rain hadn't arrived yet so I was still working with dry wood.
You can also see the new door sill in place in this last picture. Getting that installed was a project in itself with having to build up the substrate and work around the ancient existing door frame and casing. But now there's a solid door step where before only the lightest feet could tread without fear of collapse.