Heritage Restoration, Inc.

Wood Roofs

A building’s most important investment is the roof. It protects you and your stuff. It is exposed to the harshest elements from extreme hot to cold, from sun and shade, from ice to rain. I was talking to my dentist the other day, and he mentioned wood roofs and wondering what is best.

Wood roofs have a special place in my heart. I was taught by the meanest guy around. He would watch and berate me or anyone else, as mistakes were stripped back and reroofed until it was perfect. He was right, since 15 years later the roofs are still functioning perfectly in the harsh climate of Harpers Ferry, WV.

Like many of the trades, roofing has been overwhelmed with incompetent workers who think roofing is just nailing on product. They understand little about the product and less about its application. Too often we fix brand new asphalt roofs with a decent shingle application (the easiest thing to do), but very poor flashing technique that has little sensibility of the function of water (apparently the hardest).

Wood shingle roofs are beautiful, especially in the right architectural style like a traditional Shingle Style building. Yet like many things, it is not a one and done. Wood roofs take as more maintenance than your sidewalls. Leaving wood exposed to get dry and wet again and again will cause the wood fail prematurely. So use the best wood and apply a wood preservative treatment and your wood roof will last for 40 years or more! This is especially important when you can spend 4 times the cost of an asphalt roof.

Wood shingle roofs were especially popular during the earliest American settlements. While thatching was the preferred English method in the 17th century, the extreme weather of New England caused them to fail. So with the abundance of straight, tall trees, the settlers turned to wood shingles. If your house was built before 1850, chances are it had a wood roof at one time.

“The wood and application technique is not what it used to be.” Tighter grain causes less wear and rot. Straighter grain means less splitting transversely, which exposes seams and fasteners. And yes, practice makes perfect. Honestly, few practice the trade a wood shingle roofing, but there are those who get it. There is a cedar, shake and shingle organization, which provides good tips, specifications, and even acknowledges wood shingle contractors. They have some sound rules. Here are some:

Picking the best Shingle:
Best – This type of top-grade shingles are 100% heartwood, 100% clear and 100% edge grain. They are available in 16″ or 18″ or 24″ lengths.
Better – A good grade for many applications, but I would not use them on a roof; it costs too much labor to go cheaper. These are not less than 10″ clear on 16″ shingles, 11″ clear on 18″ shingles and 16″ clear on 24″ shingles. Flat grain and limited sapwood are permitted in this grade. Sapwood rots much faster than heartwood.
Economy – A utility grade for economy applications and secondary buildings. Not less than 6″ clear on 16″ and 18″ shingles; 10″ clear on 24″ shingles. Only for sidewalls or shims.

For application, basic details must be observed:
1. Shingles must be doubled or tripled at all eaves. Two with a copper or better drip edge, three alone.
2. Butts of first course shingles should project 1 1/2″ beyond the fascia and approximately 1″ over the gable or rake end.
3. Spacing between shingles (joints) should be a minimum of 1/4″ and a maximum of 3/8″. Spacing depends on how wet they are. Dry=more, wet=less.
4. Shingles joints shall be laid with a lap no less than 1 1/2″ from the course below it, or 1” on top of the nail below it. Nail shingles ½” from the edge. NO SHINERS! (Nails showing)
5. Joints must be offset 1/2” from joints two courses below cannot line up, no direct alignment in alternate courses.
6. Always stay between a 4” and 10” wide shingle, tossing smaller for shims and splitting larger.
7. I was taught to hand nail, but nail guns are a great time saver. A nail should NEVER be set lower than the wood’s face. The shingle has to expand and contract up and down, that is why the stainless steel shingle nail has a smooth shank for the last ¾” or so. They should be nailed proud, or high, then hand hammered flush.
8. Use copper, or even better, stainless steel, or tin coated copper. Copper can wear quickly with certain salt and the wood’ tannins mix.
9. Treat a wood shingle roof after the first full year with a nice oil wood preservative. Then the next year, then every 3-5 years thereafter. You will get a 40-year roof, or 25 if not treated.
10. If a wood shingle splits during install or years later, slip a 2” x 8 “ piece of copper (with a rounded top) under the crack. Friction will keep it in.

So when you invest, invest wisely.

Leave a Reply