Sealing Douglas Fir for Exterior exposure

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Forum topic by CityGal posted 06-02-2010 06:39 PM 10950 views 0 times favorited 9 replies Add to Favorites Watch
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06-02-2010 06:39 PM

Hi, I am super new to this forum and eve newer to woodworking, although I would not call myself a woodworker. My husband and I are building a chicken coop from plans we bought on the internet. The plans called for Douglas Fir and if you want to make it cost a mint you could go with a more expensive wood like Redwood or Cedar. Also, pressure treated wood is not an option as the chemicals used to pressure treat are debatable as far as their effect on chickens, organic eggs etc. My question is about protecting the wood. The fellow who wrote the plans recommended a Internal Wood Stabilizer and I just never got around to ordering it, but it is supposed to harden the wood internally and then you use a polyurethane on top of that. We are in Southern California, have mild winters and moderately mild summers. The coop has a roof that is polycarbonate, but it is clear so sun is diffused. We used a deck polyurethane sealant on it. What do you think? An I going to have a twisted deformed mess of a chicken coop after the sun has its way with it? Is there anything you would recommend? I have attached a pic.

All of your responses would be greatly APPRECIATED!!!!


9 replies so far

View a1Jim's profile (online now)


113058 posts in 2393 days

#1 posted 06-02-2010 06:52 PM

Hi welcome to Ljs
I’m not sure what is used elsewhere but in my area the pressure treated wood is treated with copper sulfate and I know an organic grower who uses it on his trees to fight white fly and I’ve also heard of a heat treated wood that has no chemicals that is good for ground contact. My first suggestion is to use pressure treated wood. If you still feel that’s not an option then you could staple or nail a row of roofing felt to the wood in contact with the soil. I would say 30Lb would be best. Hope this helps.

-- Custom furniture

View CharlieM1958's profile


15889 posts in 3034 days

#2 posted 06-02-2010 06:56 PM

As jim points out, it is not so much the sun you have to worry about… it’s having the wood rot from exposure to moisture. Try to avoid wood-to-ground contact if possible, and coat it with the best exterior grade (spar varnish) coating you can find.

-- Charlie M. "Woodworking - patience = firewood"

View hazbro's profile


109 posts in 1806 days

#3 posted 06-02-2010 07:21 PM

I’m going to be trying this product out, it looks promising.

-- measure once, keep cuttin' til it fits

View TopamaxSurvivor's profile


15413 posts in 2492 days

#4 posted 06-02-2010 10:30 PM

All the small buildings we built on the farm when I was a kid were up off the ground a vew inches on rocks, ect for a foundation to prevent rot. all the fence posts that went into the ground were treated in penta.

You need to protect it form the sun with something like paint or a clear finish with a high UV rating.

BWT, Welcome to LJ ;-)

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View Jennyjasper's profile


8 posts in 1724 days

#5 posted 06-09-2010 06:13 PM

Very Helpful! I found this information about the chemicals in pressured treated wood.

View Nomad62's profile


726 posts in 1774 days

#6 posted 06-09-2010 09:29 PM

I would recommend keeping the wood from touching the ground, say using pier blocks or the like; the poly roof will be good if you seal up the nail holes. So long as it is dry you should be okay. Keep an eye on the wood you end up buying, make sure it is reasonably straight grained; the more wavy grained boards will warp and twist over a couple years time and make a mess of things. Welcome to LJ’s!

-- Power tools put us ahead of the monkeys

View Jim's profile


7 posts in 1722 days

#7 posted 06-12-2010 01:30 AM

Well, I’m prepared to be tar and feathered, and excommunicated from this group, for this second post as a “newbie”, going against the current of popular opinion. My wife and I moved here (SE Virginia) in 1975, about a 75 minute drive each way to Virginia Beach. We got a small piece of property, raised a big garden every year, and 100 chickens, two hogs, and three head of cattle to butcher, and put in our freezer.

My father-in-law was “old school”........a West Virginian from the school of hard knocks… folks would label him as a “hillbillie”. Stacking hay in stacks (not baling it), using a scyth, and most important to your question…...........he built our chickenhouse using what he calls “Jenny Lynn” construction.

This method uses green, fresh cut lumber, with the only studs being under the floor, and the roof; all of the walls are built solely with boards. Each wall is built on the ground, then erected onto the floor. He used old creosoted used telephone poles for the foundation.

The amazing part of this old style construction, lies in using local lumber, that was never planed. 35 years of weather, mostly in the shade of our woods, without paint, shingles, or any other finish, and the building is still just fine, with just a few borer holes in some places.

The lumber was mixed hardwoods; maple, beech, gum? The key to the sheds longevity seems to be the rough cut lumber, allowing the wood to dry extremely rapidly, after being rained on.

When I retired, I started noticing a lot of the really old buildings still standing around here (like the old barn is this photo).........not the old mansions, but the laborer homes. These buildings all use a dark colored pine tar/turpentine finish on them, and appear to look very similar to a creosoted pole, without the creosote. The first formula I have found is in George Buehler’s book on wooden boatbuilding. He writes that West Coast commercial fishermen use it on their boats, and he calls it “boat juice”. A mixture of pine tar, turpentine, and boiled linseed oil. I have also read of slightly different variations of this home brewed mixture, in Woodenboat Magazine articles.

-- Just easing along; life is good.

View TopamaxSurvivor's profile


15413 posts in 2492 days

#8 posted 06-14-2010 08:25 AM

What photo?

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View sandt38's profile


166 posts in 1724 days

#9 posted 06-14-2010 06:11 PM

Citygal, Depending on where you are at in SoCal you shouldn’t really have to worry. I would raise it off the ground with some 4” cinder blocks, and poly coat it. There is so little moisture down there that it should last for years without issue. I lived in San Diego county (LaJolla) and Orange County (Lake Forest/Foothill Ranch) for 10 years and never saw enough rain to worry much. Aside from our flooding every 3 years or so at Laguna there just really isn’t enough rain to worry about it. The coop should last a good while as long as a poly coat is maintained.

With that said, my current neighbor keeps chickens, and his hatcheries and coops are all built with pressure treated lumber. I personally wouldn’t worry too much about using it. I eat his chickens and the eggs all the time… Aside from an occasional tremor I have no issues ;-). (Just kidding about the tremors)
henny is there guidelines as to what is ok to be officially organic? What about paint? what about galvanized wire and nails?

“My advice use pressure treated lumber, the chickens will not get enough of it From “leaching to hurt them or you. If you grind it up and feed it to them it probably will make them sick, if you barbecue with it it will make you sick If you want to rebuild your coop in 2-3 years use non PT lumber.

Micronized Copper Wood Preservative

You may have seen advertisements recently for a new kind of preservative-treated wood. Brand names include Yellawood MCQ, MicroPro and SmartSense. While the names are new and the properties of the wood are a little different, the preservatives used in these products are simply modified versions of existing formulations.

‘Treated wood” refers to the green-colored lumber that is widely available at hardware stores and building centers. In Tennessee , this wood is usually southern pine that has been impregnated at a factory with a copper-based wood preservative. The green color is from the copper. In the past, the copper was combined with chromium and arsenic. This “CCA” formulation was the standard for many years. About four years ago, CCA was withdrawn from residential use and replaced with alkaline copper quaternary (ACQ) and copper azole (CA). These preservatives are also copper-based but include organic co-biocides instead of chromium and arsenic. All of these formulations leave the wood green in color (unless a dye is added), clean to the touch, paintable, and protected from insect attack and rot. ACQ and CA are very corrosive to metal, however, so it is important to use only ceramic coated, stainless steel, or other approved screws and nails with treated wood.

The ‘new' products are variations on ACQ. Instead of using dissolved copper in the preservative, small particles of copper (called ‘micronized copper') are injected into the wood. Wood treated with micronized copper is less corrosive to metal fasteners and is lighter in color. It is still important to use approved fasteners with micronized-ACQ treated wood but aluminum can be used in contact with the treated wood. The lighter color can be an advantage too: The wood can have a more natural look, and lighter-colored paints and stains can be used.

-- Got Wood? --- Somewhere along the way the people in Washington forgot that they are there to represent the people, not to rule them.

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