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Wood shingle roof, Wappingers Falls NY (C) Daniel Friedman Wood Roof Shingles & Shakes Maintenance Guide

How to maintain a wood shake or shingle roof:

This article discusses the properties of wood roof shingles and shakes, including shingle grades, wood species used in roofing, and wood roof shingle or shake warranties.

This article series discusses best practices in the selection and installation of residential roofing. Our page top photo shows a wood shingle roof on the historic Mesier Homestead in Wappingers Falls, NY.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Maintenance Advice for Wood Shingle or Shake Roofs

Adapted/paraphrased with permission from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) , chapter on BEST ROOFING PRACTICES:

A number of factors affect the longevity of a wood roof. Key factors include the durability of the wood, local humidity and precipitation levels, and whether the roofing was installed with adequate ventilation.

Other factors include the slope of the roof (steeper slopes shed water faster) and the presence of overhanging trees that shade the roof and drop organic debris onto the roof, trapping moisture on the surface. Some of these factors can be controlled by the contractor; some managed by the homeowner. Others, like the weather or the reduced durability of second-growth cedar, are beyond our control.

Some simple steps that a homeowner can take to prolong the life of a wood roof include:

Over time, the natural extractives in cedar and other decay-resistant species will leach out, making the wood vulnerable to decay. Also, as the shingles dry out, they are prone to cupping, checking, and splitting. At some point, it may make sense to wash and treat the entire roof.

Washing or Cleaning Advice for Wood Roofs

Cleaning wood roofs with high-pressure equipment is controversial and, in untrained hands, can cause significant damage. It is best to use normal garden hose pressure along with a brush or pump sprayer.

To remove dirt, mildew, and weathered gray residue, a consortium of wood technology and coatings experts, including the U.S. Forest Products Laboratory (FPL), recommend a solution of sodium percarbonate (disodium peroxydicabonate) and water.

With redwood and cedar, a second wash with a solution of oxalic acid may be needed to remove brown and black discoloration caused by tannins that leached out of the wood. Concentrated oxalic acid is toxic and should be handled with care.

More information: see STAIN DIAGNOSIS on ROOFS.

Preservative Treatments for Wood Shingle / Shake Roofs

There are a number of commercial treatments available to restore decay-resistance to an aging wood roof.

One effective and relatively benign (to plants) treatment consists of a copper-naphthenate compound called Cunapsol 5, which is diluted 1:4 with water and can be applied with a garden sprayer. The treatment needs to be repeated approximately every five years.

More details: see WOOD ROOF COATINGS & FIRE RATINGS.

Oil-Borne Wood Roof Preservatives

Although Cunapsol 5 and similar waterborne treatments offer good protection against mold, mildew, and decay fungi, they will not do anything to slow down the cupping and splitting caused by weathering. For that, an oil-borne treatment is required.

Effective wood roof shake or shingle preservative treatments include copper naphthenate with a 3 to 4% metal content and copper octoate with a 1 to 2% metal content. These can be brushed on or dipped (before installation) or professionally applied with spray equipment.

Semitransparent Oil-Based Preservative Stains on Wood Roofs

Semitransparent oil-based preservative stains work well on rough-textured wood, such as shakes and shingles. They provide some pigmentation and protect the roof from decay for several years. Look for a product with both a wood preservative and a water repellent.

Stains with a high percentage of pigment provide the best protection against UV degradation. While preservative stains are best applied before installing the shingles, a surface application can significantly extend the life of a wood roof.

Treatments to Use and to Avoid on Wood Shingles and Shake Roofs

According to the Shingle and Shake Bureau, one should use only products that are marketed and labeled as a cedar roof treatment, that have an MSDS available, and that contain one or more of the following: a water repellent, UV inhibitor, or U.S. EPA-registered wood preservative. The following treatments should never be used on wood shingles or shakes:

-- Adapted with permission from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) .

 




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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-05-01 - by (mod) - fire retardant wood preservative made of acrylic melamine?

Thank you for the interesting comment, Jim.

For other readers, melamine is an organic compound that when combined with formaldehyde forms a durable thermosetting plastic.

Possible formaldehyde offgassing from melamine-products

Readers will recall reports of poisoning of babies fed formula from China that contained melamine (apparently added to water as a "fake" nitrogen supplement to meet government demand for boosted production of milk). That toxic melamine additive was also found in some pet foods.

Melamine plastics in hardened form, such as countertops, are less likely to be hazardous to building occupants, though melamine dust created during working with such materials may be hazardous to workers.

And if improperly formed, wood products that used melamine can be hazardous if the product continues to offgas formaldehyde - an event that chemists ssy should not occur if the product was made properly.

For example see

Indeed there has been a bit of research about using melamine as a wood preservative. Examples include:

Research on use of melamine as a wood preservative

Toxicity of Melamine in Some Products & Materials

Watch out: though there is some research arguing the opposite view, there is evidence that in at least some environments melamine can be highly toxic, possibly carcinogenic.

See:

On 2020-04-30 by Jim

We had good luck with a fire retardant wood preservative that was made in Texas. It consisted of acrylic melamine, and as such was a UV protectant.

Unfortunately, the company went out of business when the owner had a heart attack. We did some of the best shake roofs in California.

On 2019-11-09 - by (mod) - How can I know when individual wood shingles need maintenance or replacement?

Nate:

Some examples of wood shingle or shake damage that you might see from the ground with binoculars or from closer inspection include

- shingles missing entirely

- cracked or split shingles, particulary if the crack or split is within 1 1/2 or 2" from the butt joint of the pair of shingles below the one inspected

- wood shingles that are worn thin, curling

- rotted (rare) shingles

- leaks seen from the attic side

On 2019-11-08 by Nate

How can I know when individual shingles need maintenance or replacement?

TY

On 2018-03-02 by spike

how do I find cypress shakes
also whats the best product to clean a very old wood shake roof.
also , how do I know when the roof is beyond repair?
its a show piece , its not lived in
its in a park
its very old

On 2017-09-2 - by (mod) - wood shingle roof treatment applicable with a garden sprayer

Dave,

I would check out the wood treatments discussed in the article above and then I would go take a look at

WOOD ROOF COATINGS & FIRE RATINGS

On 2017-09-24 by davek1243@gmail.com

Hello,
I live in CT and have a cedar wood shingle roof. Can you recommend a product that would be sprayable with a garden type sprayer and available at Home Depot, etc.? Thank you very much.

On 2017-07-14 by Chris

What chemical to treat roof wood shingles for fungi, mold & moss.
Which oil to use to restore wood shingles


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