The weather report appeared to be clear for a few days in row last week so we decided it was time to start the siding. The first day was half sunny and half stormy with a brief spat of hail. This was the same storm that spawned tornadoes in Massachusetts. Despite this initial setback, we were able to work steadily the last few days.
We looked at a few different siding materials when we started the project. Affordability was a big factor, but so was sustainability and durability. Cedar is the most durable natural product but also very expensive. We rejected fiber cement because we just didn’t like the look and it seemed out of place in our woodsy setting. Vinyl looks cheap and it is certainly not an environmentally friendly product.
We settled on hemlock wood siding. It is durable, looks good and is cheaper than cedar. It is factory stained with one coat of Cabot’s (Thicket solid) water-soluble stain.
We are installing the siding over 3/8″ Sturdi-Strips furring and 7/16″ screened Cor-a-Vents at the top and bottom of the wall and above windows and doors. This provides a space behind the siding for air to circulate and aid in the drying process. We’re using this rain screen approach because the ZIP panels are OSB and we have 12″ of cellulose next to it. OSB and cellulose perform best if they can dry easily. We want to make sure they can dry as easily as possible.
We’re using metal flashing at any location water has a direct path to the wall, anytime siding meets trim, frieze or baseboard and between lengths of siding. All siding and trim is attached with stainless nails.
Here’s some snapshots with descriptions of the details.
We wrapped the window with furring strips then nailed flashing on the outside edges on top of the furring. Window trim was then installed over furring and flashing. Drip cap on top was taped to sheathing using Zip tape. Cor-a-Vent was nailed over drip cap, then the siding was notched 3/8″ over the drip cap to allow for drainage and air flow.
Frieze plate is nailed over furring. We forgot to notch the frieze trim plate before we nailed the furring and frieze, so we custom folded a J-channel below it. This detail prevents insects from getting under the frieze and shields rain from directly entering the gap. We then nailed Cor-a-Vent strips over the bottom edge of the J-channel, then slid the siding into the channel, with a 1/4″ gap at the gable edge for air circulation. We’ll notch the frieze plate for the other gable end so we don’t have to use the J-channel flashing detail.
Bottom corner trim detail
Two strips of furring at the edge, and two more offset from the edge to support nailing of the corner trim, then flashing over the furring. Screened Cor-a-Vent at the bottom for air circulation. Corner trim is nailed over this, then base trim is nailed over the Cor-a-Vent.
Corner trim with base trim installed
You can see the flashing behind the corner trim. The base and corner trim extends about a 1/2″ below the bottom of the sheathing. The base trim is notched to accept the fist layer of siding. The layer of siding above the base will be hidden by the first two courses of siding.
The first 5 courses of siding up on the north side of the house. You can see the vertical furring strips spaced at 24″ on center. We’ll pause here until the ventilation ducts are installed 4 feet above finish grade. Then we’ll continue the siding around the vent in/out-takes. The outdoor unit of the ASHP will also be installed on this wall with brackets. Then we’ll figure out how to install the siding around the brackets.