How to set Posts for Wood Fences and Wood Gates

CPW Wood Fences and Garden Gates
The Zen-ness of Post Holes

There is an appealing simplicity to digging a post hole. A manly occupation, reminiscent of splitting logs. The pure physical exertion of both are drawn back to the Boy Scouts or the YMCA with the belief in good character born from hard physical activity. So why is it that spending an entire day, several days, digging post hole after post hole brings out in us something less than character? Something closer to the sing song string of four letter words wailed out to the neighborhood in anger and frustration while struggling with thick sticky clay or webs of tree roots or chunks of shale and rock or, God forbid, that hollow clink of having cracked the ceramic housing of the main water line.

If our holes were excavated in nothing more than clean black dirt it would be all the things we anticipated when deciding to dig those post holes in the first place. The stamina of pure physical exertion, working down the line one hole at a time as if we were mowing the lawn; what we've accomplished and what we haven't is clearly identified.

When you encounter those holes with the obstructions mentioned above, you have a few options. Other than shrugging and deciding that the hole is in fact deep enough--when it clearly is not. You can rent an auger, managed normally by two men. In some cases this will help work through clay and small stones. But it will be ineffective against larger rock and if encountering roots, there is the danger of the auger yanking free of even the tightest grips.

You can work the obstructions with a long iron digging bar, driving it into the bottom of the hole repeatedly, working it loose and returning to the hand posthole digger for a few more inches progress.

You can rent a jack hammer with a spade chisel bit. To the depth of the chisel bit, and then you're back to the digging bar. You might also want to be cautious of the bit lodging itself in clay or root and the precarious wear on a bent back, working the bit free with a dead pull that might likely leave you laid up with spasms for days to come.

You can employ a sawzall with a long 8" tree bit and, for roots, cut them at the circumference of the hole.

You can pour a little water in the hole and as it soaks the soil loose, move on to the next hole.

You can hire a tractor with a backhoe auger and assuming the site is accessible, accomplish the project without breaking a sweat.

You can hire laborers lingering along the curb at the local lumber yard and with oversight and a clear layout of strings and stakes, go take a nap and return now and again to inspect the progress.

But the holes must be dug. And at the proscribed depth and to allow for the drainage bed of pea gravel and if you slight this rule, you will have a fenceline that wobbles and zags and if a fence has one guiding principle, one zen-like dictum, it is to adhere to the straight and true line.

Purchasing a CPW garden gate or fence-line can represent an investment of some stature. We need to take a moment to discuss the best procedure for setting those posts, whether the actual holes are dug by hand or by a renedt auger, insuring this componant of the project does not become your weak link in the years to come. Following the technique below will make a difference of several decades in the lifetime of the post. This method is the result of three decades of exerience, setting over 10,000 posts.

Fence height hole depth

6x6 posts

7-ft

42"

6-ft

36"

5-ft

32"

4-ft

24"

3-ft

18"

**For Fence posts

The logic is simple:

Bacteria and fungus thrive within the soil, and in areas where there is no light or air movement (particularly when the climate is warm and the air is moist). We are looking to separate the bottom of the post from the soil for this reason, as well as to create a natural drainage of the standing water than can result from surface rains and snow melts, as well as air-moisture such as fog and mist and humidity.

In the warmer, dry seasons, the post shrinks and a small crack appears between the post and concrete. With posts set in full concrete, water and moisture find their way down through this crack and begins to fester immediately in an environment without light or air. If it drains clear to the bottom, only to settle at the bottom of a post set on grade, we are essentially hand-feeding the bacteria as a ideal breeding ground.

We might also make note that their exists a hierarchy of vulnerability to this bacterial dragon. If you are in the temperate climate of the Pacific coast, the parasite population is minimal and unaccountable compared to areas such as, say, South Carolina or Southern Florida, or Hawaii, or the Caribbean, where bacteria and fungus are merely waiting for the day when humans become extinict and the earth is returned to its rightful species--parasaites. In other words, warm fetid climates are more prone to wood rot than temperate climates.

You must create a bed of drainage at the bottom of the post that is 3" deep and made up of 3/8" pea gravel (larger aggregate will not settle as well and the post, set on top of this, will ultimately shift as the larger gravel shifts over time).

Set the post in place and fill the hole 2/3rds it depth with more 3/8" pea gravel. At the top, pour a washer, or cap, of concrete that is approximately 8" thick. The water that finds it way between the shrinking post and the concrete will drain through the 8" cap of concrete and into the pea gravel where it carries on the length of the post and into the bed of 3" pea gravel, AWAY from the bottom of the post. For this reason, do not seal the bottom end-grain of the post; it must be allowed to drain out any moisture it absorbs from rain and humidity and dew and fog (Particularly true of green posts that are not air dried.. There is also no reason for you to poison the ground with toxic preservatives that will take decades to dilute to a safe level. Do you assume that the earth is yours and yours alone and that no one has inhabited this earth before you and that no one will inhabit this earth for millennium to come? We recommend you avoid the poisons.

**For Gate Hinge Posts.

Because this post carries the load of the gate and the added stress of a swinging gate, it's best to set the post in full concrete. But not forgetting the 3" bed of pea gravel at the bottom. Water drains down the length of the post between the shrinking post and the concrete and carries on a little further to finally drain away from the exposed and vulnerable end-grain.

At the grade level, extending from approximately 1" above the concrete, introduce what is known as an exterior weatherizing tape. Known as Vitchithane, or any number of names. It is a thick gray tape in 4" and 8" wide rolls with a thin film on the back that peels away for a uncommonly sticky surface. This is designed to create an impermeable seal. The only product that will do as much. The impermeable seal is the top priority; if moisture finds it's way between the tape and the post, we are again creating an area without light or air-flow and back to breeding bacteria.

For this reason, taping the length of the post is precarious, only because if in fact you do not show care in insuring the tape is applied properly and providing a sure bond, then we are facilitating the bacteria and shortening the life of the post. So it is an acceptible allowance to take the post for only one course of tape, at the concrete line.

Once again, refrain from sealing the bottom end grain of the post or using preservatives. Any moisture the posts takes on above grade will then be unable to drain away through the bottom of the post, in addition to the moisture content inherent in the post at the time of setting.

Freeze areas

For areas of deep freezing, it's always best to set your concrete cap a little deeper into the grade and to increase the thickness of the concrete proportionate to the freeze-line. In other words, the top of the cap in Chicago would be 1-2" below the grade and run about 10" thick, or deep. In Buffalo or Montpelier, VT, the cap would set 2-3" below the grade and run even deeper. Why? Cold, freezing conditions are going to contract and swell the soil so that it compresses the concrete and with nowhere to go, the concrete will work it's way up the post hole in the same manner as one of those popsicle push sticks.

Weatherizing tape can be an added seal set from 1" above the concrete cap to the depth of the concrete cap. But not advisable to tape the entire length of the post below grade. This principle has been proven out repeatedly in scenarios of posts wrapped with tar paper or posts coated with tar itself, under the guise that the post is being protected. But one must also be aware that tar contracts and cracks and is not an impermeable moisture barrier, and tar paper even worse, creating again a cavity between the post and paper without light and air.

It's a principle that unfortunately was played out in home construction for so many decades. Stud walls sheathed in code-required shear ply to provide lateral rigidity and then wrapped, or sealed, in a purported moisture barrier. In the 1950's and 60's this was plain old tar paper. In the 70's and 80's it was TVEK. What was ignored was how a house must breath, expanding and contracting with the seasons and when moisture finds its way between the seal barrier, be it TVEK or tar paper, and the plywood shearing, we have the exact same problem as described repeatedly above. The result: Rotted framing.

Below, a Fence for a patron in Washington DC, illustrating how the panels have been set lower than the specified 2" above grade. An important caveat: Keep the dirt away from your fence panels and they will last a lifetime. Within the dirt is where our eco systems exists and eco systems thrive on anything munchable. The cedar itself goes a long way in distracting this, as it has the DNA of a natural oily tannin that tiny organisms find unappetizing. And yet, in desperation (prolonged droughts) they will turn for survival to even cedar. So the 2" clearance is vital.

The same principal plays out with the longevity of the gates and panels themselves. Unlike a deck-board, in contact with joists and the joist with girders and the girders with posts and all of them like highways for bacteria to travel, the gate is not in contact with anything else. The hinges are surface-mount for this reason--maintaining a clearance between the gate and post, as well as the 2" bottom clearance. These 'perfect conditions", of the cedar and the proper post setting and the gate installation methods, all combine to provide a product that will not be prone to the ravages of fungus and dry rot.

We also want to illustrate the investment in a fence of this nature. These are lifetime products, designed and built to last, and do not allow your installer, whose experience and scope may be limited, to shrug off the methods described above.

Selecting the right material

Listing some preferred 6x6 Post Stock

Clear Western Cedar

Excellent rot resistance and representing the best option. Clear dry cedar is certainly the most visibly pleasing among all choices, but also in possession of the rot-resistant properties inherant to the tree's genetics. . Approx. $20+/ft for 6x6--. depending on your local lumber yard. Normally a special order in the west of about 1 week. This can often be 2-3 weeks back east. Seldom a wise choice for an entire fence-line and used primarily to shoulder your Gate, or an assembly of the gate and flanking panels representing a featured entry. Sustainably harvested in British Columbia.

Knotty Western Cedar
(STK)

Excellent rot resistence. Cedar knotty grade (STK) is approximately 1/3rd the cost of clear and normally with an Architectural Grade of only a few select knots. Sustainably harvested in British Columbia. In stock at most yards in the west, and a 2 week special order in the east.

Southern Cypress

Nominal rot resistence. Higher density than cedar or redwood. Sustainably harvested only in the SE United States. Available from Texas to Florida, and from Florida to the NC. These just happen to represent areas with high humidity and the ideal conditions for breeding bacteria and fungus and although Cypress has the benefit of being harvested locally, it is not an ideal choice in its own backyard.

Con-heart surfaced redwood

Redwoods grow in northern California, where Charles lives. Many of them in his neighborhood are more than 2,000 years old, including perhaps the one sidled along the west wall of the shop. Redwood harvests to an acceptably mature fiber in about 150 years. The redwood available today is harvested in 30 years with the result being a porous, fibrous property with excessive sap that is a distant cousin to the fully matured tree. The natural tannins inherent to redwood--it's greatest asset and giving it the resistance to fungus and rot--have not fully matured, with the result that it is far more susceptible to bacteria than the redwood of legend. Charles would suggest that no one use this species for anything whatsoever beyond the appreciation of their forested existence.

Clear all-heart surfaced redwood

An even greater offense. The heart, or center of the tree, with the tightest grain and oldest growth rings and in such a grove where Charles once proposed to his wife--these ancient living goliaths, alive during the march of Cortez' and the Crusades and Ceasar's Rome and just forget about redwood Fence Posts.

Synthetic
(Trek, etc)

Fiber, or Synthetic Composite Fence Posts are not as structurally rigid as wood, therefore 4x4 fiber posts should not be used for Fences over 4-ft ht. Fiber posts can be finished with solid-body stains or painted.

Eastern White Cedar

Good rot resistence. Available for those in the NE. 4x4 approximately $2/ft linear. Light knots.

Eastern Red Cedar

Okay rot resistence. Aromatic. Available as 4x4 and 6x6. 6x6 Approximately $4-$6 a foot with light knots.

Pressure-treated fir or southern pine

Pressure-treated lumber as a Fence Post is a last resort. On two levels:
1) It does not bio-degrade and regardless of what you've read or what your lumber salesmen tells you, the toxic poisons cured into the wood are not friendly to the touch (Many state codes now outlaw the use of pressure-treated lumber in public parks and schools for above-grade exposure). It also drains into the water table and contaminates not only your drinking water, but a mild annihilation of the surroundig eco system.
2) The gates and panels are going to incite fondling, while the pressure-treated posts will enact the very opposite reaction, or put another way, an uncommonly attractive woman with the breath of a muskrat.

Please insure your installer understands the preferred methods for setting your Posts. By setting your Fence Post in 3/8" pea gravel, you not only eliminate the need for toxic sealants and preservatives, you extend the life of your post by 30 years!

Gallery 1
Garden Gates

Gallery 1A
Garden Gates

Gallery 2 Driveway Gates	Gallery 3 Fences	Gallery 4 Arbors	Gallery 5 Columns	Gallery 6 Benches / Swings
GATES Pricing	FENCES Pricing		DRIVE GATES Pricing	COLUMNS Pricing

1. 8 0 0 . 4 6 6 . 1 8 5 0
1 .7 0 7 . 8 2 3 . 3 7 1 1 (PST)
1 . 7 0 7 . 8 6 1 . 3 4 0 9 (FAX)

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CPW Wood Fences and Garden Gates The Zen-ness of Post Holes