Do yourself a big favor, and if you are going to pour concrete use steel.
If you insist on the 4 x 4, set it on a concrete donut or pad, and backfill
it with stone. The 4 x 4 will not last (over 20 years) in concrete unless
there is very litle moisture, and much of a side load will snap it off just
above the concrete. Setting it in stone will help with the water, and allow
enough give to avoid the shock load. One other option not mentioned yet is
that if you are going to pour concrete, pour the post as well. Use a PVC or
cardboard form, make sure you use re-bar.
The post building industry is trying hard to find a solution to putting wood
into the ground with the wood and treatments that can be used today. Hedge
might give you 30 years, but that about the only choice.
If you use steel, don't use anything that would that would hold moisture. H
or I beams are what I use.
This is because concrete over 4000psi is supposed to be waterproof. Low
grade concrete will wick water, but the higher grades will not. Bridge
supports don't wick water, and they are concrete. Either bury the post
deeper than normal, or set it in high psi concrete. It will probably be
eaten by a critter before it rots. By the way, .60 treated southern
yellow pine should be much better than redwood. Its what they use to
build wood foundations which are burried for life.
On Wed, 27 Oct 2004 08:27:39 -0500 "Keith Dutson"
<kjdutson@earthlink.net> writes:
> My barn is built on 4X6 20-foot Wolmanized pine posts set in concrete
> to a
> depth of 4 feet. It was erected in 1977. There is no evidence of
> rot.
>
> Keith NM5G
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Tim Makins,
> EI8IC
> Sent: Wednesday, October 27, 2004 1:31 AM
> To: TowerTalk
> Subject: Re: [TowerTalk] Mounting a 4x4 in concrete
>
> I think setting timber in concrete is a bad idea. Water can get in
> around
> the timber and cause rot. Why not set a length of steel I-beam or
> similar
> into the concrete, and bolt the timber to that ?
>
> 73s Tim EI8IC
> www.mapability.com/ei8ic/
> Ham Map Heaven. Newbie and Contester Resources. APRS stuff.
>
> ----- Original Message -----
> From: "Derek Cohn/WB0TUA" <vibroplex@mindspring.com>
> To: <towertalk@contesting.com>
> Sent: Wednesday, October 27, 2004 5:45 AM
> Subject: [TowerTalk] Mounting a 4x4 in concrete
>
>
> Dear All,
>
> I'm trying to elevate my very low dipole that is fed with balanced
> line.
> I'm trying to go with a non-metallic support so the balanced line
> does not
> interact. My dipole is currently 18' in the air.
>
> I recently purchased a 22' fiberglass mast from The Mast Co. This
> is their
> heavy duty windsock pole. I'm planning on mounting it to a 20'
> redwood 4x4
> with the Kwik-Block mounting blocks they also sold me. I plan to
> set the 4
> x4 in concrete.
>
> I checked around and one of the local deck builders says I need to
> put about
> 4' of the redwood 4x4 into the concrete. That would reduce my
> effective
> height of the 4x4 to 16'. If I overlap the fiberglass mast a foot
> or two, I
> have 16' + 20' = 36' which is roughly double the height I have now.
>
> What do you guys think about the 4' of 4x4 into the ground. Too
> much, too
> little, just right? I noticed that you can put l-bolts into the
> concrete
> footer and mount a u-shaped bracket on top of the footer that will
> accept
> the 4x4. This is advertised for deck applications and I think it
> wouldn't
> support 20 feet of 4x4. However, it would give me four more feet of
> height
> if it could be made to work. Has anyone tried this?
> Sent: Wednesday, October 27, 2004 1:31 AM
> To: TowerTalk
> Subject: Re: [TowerTalk] Mounting a 4x4 in concrete
>
> I think setting timber in concrete is a bad idea. Water can get in around
> the timber and cause rot. Why not set a length of steel I-beam or similar
> into the concrete, and bolt the timber to that ?
>
>
> Dear All,
>
> I'm trying to elevate my very low dipole that is fed with balanced line.
> I'm trying to go with a non-metallic support so the balanced line does not
> interact. My dipole is currently 18' in the air.
>
> I recently purchased a 22' fiberglass mast from The Mast Co. This is
their
> heavy duty windsock pole. I'm planning on mounting it to a 20' redwood
4x4
> with the Kwik-Block mounting blocks they also sold me. I plan to set the
4
> x4 in concrete.
>
> I checked around and one of the local deck builders says I need to put
about
> 4' of the redwood 4x4 into the concrete. That would reduce my effective
> height of the 4x4 to 16'. If I overlap the fiberglass mast a foot or two,
I
> have 16' + 20' = 36' which is roughly double the height I have now.
>
> What do you guys think about the 4' of 4x4 into the ground. Too much, too
> little, just right? I noticed that you can put l-bolts into the concrete
> footer and mount a u-shaped bracket on top of the footer that will accept
> the 4x4. This is advertised for deck applications and I think it wouldn't
> support 20 feet of 4x4. However, it would give me four more feet of
height
> if it could be made to work. Has anyone tried this?
>
> 73,
>
> Derek Cohn
> Morse Telegraph Club - Alton Chapter
> Telegraph Office UD, sine DJ
> Amateur Radio Station - WB0TUA
> 1969 M274A5 Mechanical Mule
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
any
> questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
any
> questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
--
Bob Nielsen, N7XY n7xy (at) n7xy.net
Bainbridge Island, WA http://www.n7xy.net
------------------------------
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End of TowerTalk Digest, Vol 22, Issue 100
******************************************
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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