Published on October 20th, 2018 | by Henri0
Re-siding with cedar clapboards
Q. My question for you is about the correct way to redo the siding on our house. Our house is a Garrison colonial style built in 1985. I like the look of the traditional wood siding with canyon grey semitransparent stain. Over the 33 years the spruce clapboard siding has cracked and cupped extensively especially on the south side of the house. I think the siding needs to be replaced especially on the south side.
The siding is nailed directly to oriented strand board sheathing. There is no house wrap Tyvek or tar paper, but the joints in the sheathing have been heavily caulked, so the house has been fairly tight with little air infiltration. The sheathing seems to be in good condition. I am leaning toward replacing the siding with class B cedar clapboards, though I have not ruled out using Hardiboard.
My questions deal with your thoughts on Hardiboard and with how to best apply the cedar siding. A friend of ours house had cedar siding applied directly over Tyvek house wrap. The oil in the cedar effectively blocked the Tyvek water vapor permeability and most of his sheathing rotted from water vapor coming from inside his house. When he replaced his sheathing he used tar paper instead of Tyvek and went with Hardiboard instead of cedar siding.
I am still leaning toward cedar because of the look of our house. The lumber yard has recommended that cedar siding should be applied with a rain-screen constructed with furring strips to provide a vent space to dry the back of the siding. There are commercial plastic wraps that provide a breather space for example “home slicker rainscreen” (benjaminobdyke.com ), WaterWay (www.stuccoflex.com ), DriWall (www.keenebuilding.com.)
Do I need a house wrap? If so, what would be the best wrap to use? And do I need a rain screen to provide a vent space behind the siding?
A. You are fortunate that the OSB sheathing is still in good shape in spite of the clapboard installation. I have seen a number of cases where this type of installation resulted in rotting OSB because it can’t take many wetting before beginning to disintegrate.
I am with you; cedar clapboards are best for your style house and this is how to install them properly for a long lasting job:
- Prime all sides of the cedar boards before installing them.
- Install housewrap over the sheathing as protection against any weather infiltration.
- Provide a rainscreen either with vertical furring strips 16″ on center or use one of the commercially available rainscreen material available in building-supply houses. Benjamin Obdyke Home Slicker Plus Typar offers a product that, in one operation, provides housewrap and rainscreen.
- Follow instructions on the nailing of clapboards to avoid “waving” of the clapboards caused by nailing too hard in some places, crushing the Home Slicker.