Quality Cedar Shingle Siding | Southern Maine Siding

Left natural, cedar shingles go silver-gray and need no paint, and that weathered look is the heart of the Shingle Style New England architects made popular. A stained wall is another matter: the Forest Products Laboratory puts semitransparent stain at 4 to 5 years on a south wall and more than 10 on a north one, so each side keeps its own clock.

Grain matters more than most owners expect: the laboratory says flat-grained shingles shrink and swell almost twice as much as vertical-grained ones. The bureau's Blue Label grade of western red cedar is all clear heartwood and edge grain.

Mildew and algae turn up on aging cedar, finished or bare, and the laboratory calls that growth cosmetic. It comes off with an oxygen bleach and a garden hose, while a pressure washer strips wood fiber and shortens shingle life.

Within 15 miles of salt water the bureau calls for Type 316 stainless nails, and farther inland it also allows Type 304 stainless or hot-dipped galvanized nails meeting ASTM A153 Class D. We never use electrogalvanized nails: the bureau says they corrode and stain, and the laboratory traces the blue-black streaks on old cedar walls to iron reacting with the wood.

Eastern white cedar makers call for a 5-inch exposure on 16-inch shingles and two nails per shingle, set 3/4 inch in from each edge and an inch above the butt line of the course that will cover them. We offset joints at least 1 1/2 inches course to course and never line them up across three courses.

Behind the courses, every window gets flashed and every spot where a roof edge dies into a wall gets a kick-out, so roof water lands in the gutter. Over foam sheathing the laboratory calls a rain screen necessary: horizontal 1 by 4 boards on vertical furring, vented top and bottom and screened against insects.

James Hardie fiber cement is our pick over cedar for a clapboarded colonial that should stay a lap wall, or for an owner who wants a painted color instead of weathered wood. It also averages less per square than cedar, which adds up on a big two-story house.

LP SmartSide engineered wood lap makes sense on a 1970s or 1980s ranch where the budget points to a board and the street does too. Most people asking for cedar picture a gray cottage; on that house, or on a cape that wore cedar before someone covered it, the money belongs in shingles.