Fence post questions
I’m going to install several hundred feet of three rail fence – 4×4 posts and 2×6 rails. The posts will be set in concrete.
Do I need pressure treated posts, or will plain DF be ok?
Is an 8″ diameter hole (2′ deep) adequate for a 4×4?
My paint store rep has suggested solid stain instead of paint. Will the stain work on PT if PT is required?
Thanks,
Jack
Replies
Do I need pressure treated posts, or will plain DF be ok?
You need PT posts. Doug Fir will rot in a few years.
Is an 8" diameter hole (2' deep) adequate for a 4x4?
Yes
My paint store rep has suggested solid stain instead of paint. Will the stain work on PT if PT is required?
Yes, or you might want to think about translucent stains. Stains can be easier to maintain over the years, since re-application does not generally require scraping, sanding, and priming. Either of these will work on PT, or on non-treated wood.
Do yourself a favor and use pressure treated 4x4's otherwise you'll be replacing your fence posts in a few years. I would go 30'' to 36" deep, I would not use concrete as it tends to hold the moisture around the post (I've replaced plenty of PT posts set in concrete that rotted).
8'' dia. post hole is fine,use gravel to back fill the post holes. The gravel allows the water to drain away from the post, tamp the gravel in around the post. the only post I would set in concrete is a post with a gate attached to it.
Paint or stain is fine but I would wait at least 3 to 6 months before I paint or stain PT matl.
Of course these are just my opinions and its the way i set my posts etc.
good luck on your project !
Dip the ends of the post in a good paint, let dry, then set in concrete.
My theory is, when bare wood come in contact with fresh cement, the wood fibers absorb and swells up. When the concrete drys out, the wood shrinks, the resulting gap traps and hold moisture leading to the rotting of the ends of the posts.
The first few inches of soil is where the rot happens. Look at any old post, and you will see what I mean. Has to do with the microbes that live at that layer.
One fencing contractor I know sets heavy steel angle in concrete or any pack mix(depending upon stress), then bolts the wood posts to the angle. Having replaced a gazillion rotted posts, this seems like the ideal solution. This way, you can use cedar, DF, or whatever you want. As a bonus, the fencing can easily be removed for maintenance or access to the fenced area. My next project will be done this way. Sure, the angle may rust someday, but we are talking several decades.
I've seen cedar posts fail in just 5 years.
We built a cattle shed in '76 with 4" by 5" treated posts, wrapped the ends in black felt roofing paper and cemented them in. In those days we bought cement in sacks, used our own gravel and sand from the creek and mixed all in a wheelbarrow.
They are still in perfect condition today.
Thanks for the input. Pressure treated it is, with some other enhancements as suggested
Jack
around here the old folks will dip the ends in tar and diseal fuel, they claim it help scare off termites, and yes around here termite eat PT, not that much but they will get into it.