Slight OT: Redwood Fencing?

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"fftt" wrote: ====================================Your concept is good but the devil is in the details.
NONE of the Simpson post bases / column bases are designed / meant to be used in free standing post configuration (ie a fence post or flag pole) Read the catalog notes.
A 4x4 post embedded in concrete in the ground has a decent "moment capacity". To get a fence post connected to a "concrete chunk" via a metal connector to perform the same as an embedded post requires a bit of design; especially the fastener size and pattern.
Its not as simple as it appears ....... a moment capable connection; wood to concrete via metal connector winds up being a pretty hefty piece of hardware =================================== Agreed.
If you go back and check my post, you'll notice that 10 GA metal (1/8"+) is spec'd as well as standard 1/2", "J" bolt anchor bolts in the concrete.
You will need at least a 3/8" inside radius for the 90 degree turn to minimize stress concentrations. (You need a press brake operator with a little talent<grin>)
Think of this as a 30 ft tall lighting pole, secured with four (4) mounting bolts to a concrete cylinder.
The design approach is similar.
I doubt anything in the Simpson catalog comes close to the above.
You will have a better chance finding something in the Valley pole catalog.
Lew
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Lew-
You're preaching to the choir.......
and your design, though sound in concept, won't do the job unless you go a ways up the post
Simpson has no catalog items to do the job either .....BTDT
Connecting a wooden fence post to a concrete embed is not the same as connecting a metal flag pole, traffic signal pole, etc to its foundation.
The wood to metal load transfer will be the weak link.
What is the moment capacity of 4x4 fence post? What is the moment capacity of your metal embed? What is he moment capacity of your proposed metal to wood fastener pattern?
KInda hard to fully develop 4x4 moment capacity with through bolts plus cross grain tension will bite you. Not to mention the inevitable sloppiness in the connection. You'll have better luck with lags. Out of plane strength will be decent but in plane (all the fence) will be rather low unless you have straps on all four faces.
cheers Bob
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"fftt" wrote:
======================================You're preaching to the choir.......
and your design, though sound in concept, won't do the job unless you go a ways up the post ======================================You don't like a 12" strap then make it 18".
The bending load is handled by the metal, the wood is just along for the ride. =====================================Simpson has no catalog items to do the job either .....BTDT =====================================That was my reaction to Tom V's post. =====================================Connecting a wooden fence post to a concrete embed is not the same as connecting a metal flag pole, traffic signal pole, etc to its foundation.
The wood to metal load transfer will be the weak link. =================================== Not sure I follow you. =====================================>What is the moment capacity of 4x4 fence post?
Could care less.

The metal is not imbeded.
You can calculate the section modulus based on a 3-1/2 square with 10 GA walls on the two (2) opposite sides and none on the other, if you like.

proposed metal to wood fastener pattern?
None required, the wood is trapped by 3" wide straps and thru bolts. The bending load is handled strictly by the metal.

plus cross grain tension will bite you. Not to mention the inevitable sloppiness in the connection
You lost me.

Lags are guaranteed to mess up. Much prefer metal plates thru bolts with ESNA (Aircraft) stop nuts.

be rather low unless you have straps on all four faces.
Straps must face fore and aft to handle the wind, snow, etc load.
The lateral sides of the post do not require straps since the fence will serve as diagonal bracing.
Lew
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Another Solution:
Plastic electrical conduit is Sch 40, gray PVC, 10 ft sections, and is suitable for above or below grade installation.
Install 3" conduit with gravel surround about 24" below grade then fill with sand to about 12" above grade.
Cap top of pipe is optional.
Attach fench with wrap around clamps not thru bolts.
If you don't mind gray color, you will be happy with longevity.
If you do mind gray color, it will be like ugly on an ape.
Have fun.
Lew
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wrote:
Lew-
Your concept is good but the devil is in the details.
NONE of the Simpson post bases / column bases are designed / meant to be used in free standing post configuration (ie a fence post or flag pole) Read the catalog notes.
Totally agree, IMHO they need to be a heavier material, aproaching 1/4" thick and extend up the pole at least 24".
A 4x4 post embedded in concrete in the ground has a decent "moment capacity". To get a fence post connected to a "concrete chunk" via a metal connector to perform the same as an embedded post requires a bit of design; especially the fastener size and pattern.
Its not as simple as it appears ....... a moment capable connection; wood to concrete via metal connector winds up being a pretty hefty piece of hardware
Gotta agree there too, there comes a point where digging a hole large enough to handle a large enough diameter cylinder, positioning the bracket and handling the extra concrete becomes a much more labor intensive job than probably replacing the fence again. For longevity I still believe a galvanized steel pipe is going to be the simplest and best bet.
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Leon-
I've designed & built moment resistant post bases where there was NO wood to concrete or wood to soil contact. They are HEFTY pieces of hardware and look like crap, only suitable for "hidden locations"
I agree that a galv pipe into concrete is the strongest, simplest way to go. But the pipe has to be pretty large & the pipe to post connection is hard (imo) to make decent looking. Simpson makes some pipe to wood connectors (like large pipe straps) but one still winds up with the pipe showing unless you "box out" the pipe.
I've yet to see or develop a concrete / connector / post solution that reduces rot / termite issues AND looks good enough to satisfy the customer. :(
I think the best looking, quickest, easiest, cheapest solution is a treated 4x4 in concrete over gravel using the heavy treatment (not the home depot stuff).
cheers Bib
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wrote:

Leon-
I've designed & built moment resistant post bases where there was NO wood to concrete or wood to soil contact. They are HEFTY pieces of hardware and look like crap, only suitable for "hidden locations"
I agree that a galv pipe into concrete is the strongest, simplest way to go. But the pipe has to be pretty large & the pipe to post connection is hard (imo) to make decent looking. Simpson makes some pipe to wood connectors (like large pipe straps) but one still winds up with the pipe showing unless you "box out" the pipe.
Actually it is not uncommon to see a fence, along the coastal areas, with chain link "terminal" posts for the regular posts. There are wrap around brackets that allow the attachment of wooden 2x4 rails readily available at most home centers. You certainly want the termanal posts as they are approximately 2.5-3" in diameter. The normal smaller posts would not be suitable. If you really wanted to strengthen the post you could fill it with concrete also. Actually these also look pretty decent .
I've yet to see or develop a concrete / connector / post solution that reduces rot / termite issues AND looks good enough to satisfy the customer. :(
I think the best looking, quickest, easiest, cheapest solution is a treated 4x4 in concrete over gravel using the heavy treatment (not the home depot stuff).
cheers Bib
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If you dip the posts you are just creating a vessel hat will hold in any moisture that gets into the wood, helping it rot quicker (this is just my speculation).
Standard approach the fence guys I know (who care about their work) is to over dig the depth about 6 inches. Fill the extra six inches with gravel to create a French drain of sorts so the post will never be standing in water (at least not for long.) Then also over fill the concrete slightly so you can crown it an inch or two above grade so any water drains away and doesn't pool.
Alternative is some sort of Simpson post holder like a column base http://www.strongtie.com/products/connectors/LCB-CB.asp . One trick is to use some sort of standoff to hold the bottom of the post above ground. The Simpson items called a post base have this built in but they don't have enough attachment to the post, just a few nails. You don't really need sono tubes, just some careful placement of the embeds. I like to hang them in the hole from some temp structure and use a soupy mix of concrete so it pours in and levels easy.

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If you dip the posts you are just creating a vessel hat will hold in any moisture that gets into the wood, helping it rot quicker (this is just my speculation).
Agreed!
Standard approach the fence guys I know (who care about their work) is to over dig the depth about 6 inches. Fill the extra six inches with gravel to create a French drain of sorts so the post will never be standing in water (at least not for long.) Then also over fill the concrete slightly so you can crown it an inch or two above grade so any water drains away and doesn't pool.
It is OK for the post to be standing in water when it rains, you don't want them standing in a naturally wet area when the weather is dry, they need to dry.
Alternative is some sort of Simpson post holder like a column base http://www.strongtie.com/products/connectors/LCB-CB.asp . One trick is to use some sort of standoff to hold the bottom of the post above ground. The Simpson items called a post base have this built in but they don't have enough attachment to the post, just a few nails. You don't really need sono tubes, just some careful placement of the embeds. I like to hang them in the hole from some temp structure and use a soupy mix of concrete so it pours in and levels easy.
The problem with most of these above ground anchors is that they are designed for something else to stabilize the other end of the post, like a deck or porch covering. For a fence post application I am afraid the fence might fall down with the first moderate gust of wind. IMHO the posts need to be in the ground a minimum of 20-24".
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I missed the beginning of this thread. I would just note that in my experience in the mid-atlantic area, a CCA pressure treated SYP post will last at least 25 years buried directly in the ground. I have PT posts that have outlasted 2 generations of cedar pickets and are now holding up their third. I cannot say if the newer PT chemicals will hold up as well as the old CCA formula, but it seems that all that concrete and metal is overkill .
--
Make it as simple as possible, but no simpler.

Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar. org
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How about a hybrid approach then... gravel the bottom of the hole as standard, but also paint the SIDES and only the sides of the post with resin so the wood does not directly contact the concrete. Moisture can still leave through the endgrain into the gravel/french drain.
The post-holder/post-base style of construction certainly has merit, but only if the metal holder can extend about 2ft up the post--no structure above, a huge wind load, and 50mph gusts every year. Of course metal posts would be nice too, but would cost $$. Besides, some of the fence will be shared with various neighbors and getting everyone to agree on a 'non-standard' look might be difficult.
Many thanks for the ideas so far. This is very helpful.
Cheers, Shawn
PS: Just as an aside, what lasts longer in ground-contact, redwood or PT (assuming GC level treatment)?
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Sounds OK, I just don't think ambient moisture from the concrete is going to be an issue. It is the standing in wet water that will cause decay. But what the heck, maybe dip them in thompsons water sealer and let em soak some of that up (p.s. I'm serious about that but I think the PT is pretty much already taking care of that.)

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the first set of fence details you posted is great
but
NONE of the Simpson post bases / column bases are designed / meant to be used in free standing post configuration (ie a fence post or flag pole) Read the catalog notes.
From the catalog
Post bases do not provide adequate resistance to prevent members from rotating about the base and therefore are not recommended for non top- supported installations (such as fences or unbraced carports).
cheers Bob
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Sure it is. It certainly is not a Tupperware party.

Sounds like it is way past time.

Good Pressure treated should not rot for 20+ years. But if you have soft ground the fence will probably fall over but much sooner if you do not use concrete to anchor the posts. Been there and Done that.

Alternatively, use steel galvanized chain link terminal posts. Those can be masked with pickets or painted if you do not want to see the silver post and in addition to probably being easier to handle should be much less expensive. Be sure to concrete them in also. There are many types of brackets sold, commonly where you would buy the steel posts, that will let you attach the wood fence rails to the round steel posts.
Additionally if you attach a 1x6 PT board horizontally and level along the groung on the picket side of the posts you can use that board to set the pickets on. This will allow you to put the pickets up much faster and evenly, and it keeps the ends of the pickets off the ground which extends the life of the pickets. If the PT horizontal board rots it is much easier replaced than the whole fence.
Keep in mind also that PT pickets tend to warp badly over time, you want to run a minimum of 3 rails between each post to attach the "near" top, middle, and "near" bottoms of the pickets to.
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Why not dig a hole, fill with concrete and put in a 4x4 bracket that ties into the concrete and gives a water drip away area and holds a 4x4.
These are used on Deck footings. A post can be replaced easily. The metal is thick and long lasting. Lots of capability at the Nor Cal lumber Yards - (I, a long time resident who moved home ).
Martin
Rima Neas wrote:

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Rima Neas wrote:

Another technique you might try is metal posts anchored in concrete. You can then attach the 4x4s to the metal posts with none of the wood touching the ground.
This arrangement is not only immeasurably stronger but almost immortal.
In my neighborhood, houses on each side of a power-line easement were fenced. On one side, every house had metal posts; on the other side every house had wooden posts. After Hurricane Yikes last November, about 60% of the wooden-post fences were down. None of the metal post fences were much bothered by the winds.
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