Picket Fence Lumber Selection

A discussion comparing the pros and cons of treated wood, second growth Cedar, and other wood species for use in a fence. December 1, 2010

I'm going to build a picket fence for installation in the spring. The fence is for our own historic school house shop property and the work will give us something else for the guys to do when things get a little slow. My experience with western red cedar in recent years is that the old growth lumber is gone and the new growth lumber does not hold up well outdoors. As such I'm thinking about using pressure treated 2x2's for the pickets. 1 1/2" picket, 1 1/2" space, 1 1/2" picket etc. This makes a very nice looking fence.

For the rails I can go with pressure treated 5/4 stock or use some 3/4" western red cedar resaw rippings I have on hand. I'm not nearly as concerned about the rails holding up over time as the pickets. I have found with picket fences that more often than not itís pickets that fail.

I'm wondering though if there might be some sort of negative interaction between the pressure treated pickets and the cedar rails. Does anyone have any experience with this?

Forum Responses
(Architectural Woodworking Forum)
From contributor S:
I wouldn't use pressure-treated lumber for any purpose. Aside from toxicity, high cost, the inability to stay straight, lack of testing, no real-world experience, and marketing b-s, you'll need to use stainless and/or G-90 galvanized fasteners and hardware.

The difference between G-90 galvanizing and say, G-60, is the thickness of the galvanizing. "Flash galvanizing", which is what you might run through your nail gun, is the thinnest. In other words, the manufacturers want you to use the thickest galvanizing there is, because they know the chemicals in the (treated) lumber will attack the fastener. My guess is they (the manufacturers) are simply trying to stave-off lawsuits for as long as possible.

I think I'd try to find some thirsty, inexpensive, open-grained lumber and use a quality, polyurea coating. Properly coated, the lumber will be waterproof, UV-proof, and re-paintable in the future. The fence would likely outlast you.

From contributor D:
My back deck is western red cedar pickets with pressure treated pine decking. It is 20 years old and in need of repair. Most of the houses on my block have had theirsí torn down and rebuilt already. The pressure treated was heavily warped and many nails were loose and rusty when I bought the place a couple years ago. I pulled up the nails and screwed in some galvanized deck screws, then used a floor sander with 24 grit to even it out, sanding some parts down maybe a 1/4". Two years later it's warped and cracking again. I wish I'd just torn it out and used cedar throughout, with black locust posts.

From contributor O:
I agree that the traditional western woods - cedar and redwood - no longer have the durability with the second growth logs. I also agree that treated SYP is the worst thing in the world that can still barely pass as lumber. You may try sourcing some old growth woods locally if there are any reclaimers in your area. Almost any old growth species (pine, oak, etc.) is better than almost any second/third growth. Even the old, high density doug fir will work well for your use.

Next, I'd use Spanish cedar, or white oak or cypress. They paint well, and are good in the weather. Old growth cypress or oak will be preferred. You do get five bonus points for not even mentioning the PVC plastic fence. I like to see woodworkers employed.

From the original questioner:
I get your point that P/T is nasty stuff. However, figure Spanish cedar, African mahogany, sapele, etc and you are talking minimum $3 to $4 per board foot. Divide this out and you are talking costly 3' pickets.

I have a close friend who owns one of the local lumber yards. He has a load of old stock (read: drier) 2x2 clean, clear and straight P/T balusters. I am well aware of potential problems with P/T (this gray hair didn't just happen on its own) and hope I have learned enough over the years to help cull out most of the potentially problematic sticks. With good planning on construction I can build this 125' fence so that any warped picket can be removed by taking out two screws (stainless or galvanized needs to be determined).

Just a point of interest here. I built a very long picket fence about 25 years ago. When it was taken down last year the wood was still sound but the fasteners (not galvanized or stainless) had failed. The rails were P/T but the pickets were re-sawn spruce 2x4ís. I had cut four 3/4" x 1 1/2" pickets out of 32" long 2x4s, and obviously three 32" blanks per 8' stud - a very economically built fence.

Another fence I put together about 15 years ago is in mixed condition. The rails were of pine and are a mess. A section with pine pickets is also a mess. However, a section built with the P/T rails and 3/4" x 2 1/2" furring strips for pickets is very sound. You never quite know what to expect I guess.

From contributor M:
I don't buy a lot of screws from Mcfeely's, but they do have a good guide in their catalog for fastener use with different woods regarding corrosion. It might be worth checking. For the same above reasons, I don't like pt wood. You can't prime and paint it properly. If you do it before assembly, itís too wet. Afterwards you can't get to areas where the lumber meets. And this is where it rots.

I vote for cedar and cypress. Even new growth is better than pt I believe. Maybe considering some diy treatment would be beneficial, such as a borax type treatment. I run into your dilemma all the time in selecting wood for exterior shutters. I use the best wood possible, and since we mostly paint our panels, I depend heavily on the best quality primers and paints to offset the effects of nature. Regardless of clear or painted finish, I double or triple prime or seal the end grains as much as possible.

From contributor S:
Have you ever worked with yellow cedar? I used it for some rather elaborate railings on an outdoor deck. The customer didn't want to have to replace them every ten years so we tried yellow cedar. That was over 20 years ago now, and they are the same as the day they went in. They have been diligent about maintaining the paint job, which I think has a lot to do with it . It is used a lot for boat building from what I am told.

From contributor M:
You may ask your lumber supplier about African mahogany shorts or outs. There always seems to be a fair amount of sticker stained mahogany floating around which could get you down to the price of good cedar.