Cedar for Outdoor Furniture
A discussion of the health issues concerning Cedar sawdust, and of fastening and strength issues. December 6, 2011
Question
I have a customer with an outdoor furniture line they want us to machine from western red cedar. Our first trial run has been very difficult because of the affects the dust has had on our employees. Also, we aren't sure if the weaker cedar is best suited for outdoor use without using huge lag bolts to join everything and very thick wood. These products are somewhat ornate.
Is there a better wood for outdoor furniture that our customer would hopefully consider high end? They won't accept pine or fir. What else is out there that won't be too expensive to produce monthly shipments?
Forum Responses
(Sawing and Drying Forum)
From contributor A:
There is redwood and eastern red cedar and cypress along with white cedar from the east coast. I know some folks react to ERC dust but I have not known of many who have a problem with cypress or white cedar. All of these woods do well outdoors and are a fine product.
From contributor S:
Your problems sound unusual. Any dust in a manufacturing environment is an issue, and dangerous. It doesn't have to be wood dust - just fine particles. I cut cedar all the time, many of us do, and it is essential to limit exposure. If I worked in a dusty environment all day just about any wood dust would cause me a health problem.
You can research the construction strength characteristic of WRC and you will find it is on par with many other commonly used woods (hemlock, fir, and spruce to name a few). So I am guessing your other products are made from harder and stronger woods that could be fastened differently. Fastening WRC can be done with a bunch of different methods. These methods are used in the marine, timber frame, and home construction industries.
From the original questioner:
What options are there for fastening cedar or other softwoods for outdoor use?
From contributor M:
I'm not much of a carpenter but I do cut a lot of WRC. If you breathe the dust, long term exposure will lead to a cedar allergy. A paper mask is sufficient to filter it out if you don't have enough ventilation at a particular work station.
As for fastening, it is a wood that splits easily with the grain, so it is best to avoid high stress joints at the end of a board. Those fancy little extras that extend the board past a joint are not just for decoration.
As far as using another common softwood goes, the only way to get anywhere near the same longevity would be to use pressure treated wood. I have an uncle who recently rebuilt his fence with new posts after 25 years. He pressure washed the old cedar fence pickets and nailed them back up looking like they were new.
From Professor Gene Wengert, forum technical advisor:
Western red cedar is a known carcinogen, with people exposed to the dust having an increased risk of nasal cancer historically. It seems to be worse than other species. Species with natural decay resistance do have chemicals in them that kill fungi and oftentimes insects. The fine dust of these species exposes workers to these chemicals. Some species even have contact dermatitis issues for some people.
From the original questioner:
I agree. We have been sneezing ever since. We may go with a less caustic wood and try to apply a coating, but also put a warning/disclaimer label on the furniture. Not sure which coating I will use yet.
From contributor B:
From what I have seen, exposure to western red cedar dust certainly has caused cases of occupational asthma, but I don't believe there are identified links to nasal or other cancers.
From contributor S:
Most marine fastening I have observed consists of extra steps with traditional methods, such as: Pine tar added onto the thread of the wood screws, the holes for the wood screw drill with a tapered drill, the screws themselves large diameter, solid wood plugs glued in over the screw heads using waterproof glue. Large member connections are bolted together and joints are scarfed together. Grain direction is controlled, frames are horizontal grain, planks and decking are vertical. In large tension areas full length bolts are used to ensure things stay together. Lastly materials that are mounted to each other are beaded in, using a beading compound that keeps moisture from penetrating the bed.
From the original questioner:
That makes sense. I think this can also work if those particulars are met. I think the only things we're lacking is the pine tar for the 3" long lag bolts we use and some of the rail work is too lightly affixed to their posts where it needs beefier bracketing. So where can I buy pine tar?
From Professor Gene Wengert, forum technical advisor:
The original interest in wood dust was the result of some rare nasal cancers in woodworkers in England who had been exposed to WRC dust. As contributor B says, WRC dust is no longer thought to be any more carcinogenic than other wood dusts, which means wood dust exposure does have a small risk. Appreciate that many of the older reports about wood dust damage were from workers in factories that had clouds of dust and little dust control. Today, such conditions do not exist within the industry.
Source: www.nclabor.com/osha/etta/indguide/ig19.pdf
Here is a quote:
"The domestic wood most frequently associated with respiratory tract allergy problems is Western red cedar (WRC). This wood is grown in the northwestern U.S. and western Canada. The effects of this wood have been carefully studied. The higher the exposure levels of WRC dust, the greater the number of workers having asthma. In one study, 5 to 24 percent of those working with WRC had asthma. It generally takes from weeks to a number of years of exposure to develop symptoms. Often at first there may be just nasal irritation, sneezing, coughing and then wheezing. Symptoms may tend to be worse at night, and relief occurs over the weekend. However, with continued exposure, signs such as fits of coughing and wheezing become progressively worse, occurring in the afternoon or evening and, in some cases, immediately after exposure. If exposure continues, symptoms continue during weekends so that they resemble chronic asthma or bronchitis. Though asthma tends to improve after exposure has ceased, some individuals will continue to have asthma for indefinite periods."
From contributor S:
I just searched under marine pine tar and found several sources. Most supplies that support boat construction should have it.
From contributor D:
I'd like to suggest old growth heart cypress or redwood material reclaimed from pickle vats. It lasts far better than WRC, is stronger, better looking and cheaper. (And I sell it.)
