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Author Topic: tower in ground  (Read 626 times)
W9ACF
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Posts: 2




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« on: May 23, 2002, 04:33:57 PM »

I was wondering.....

If I was to take a 55 foot tower and attach it to the side of my home, would I still to to mount it in concrete, or do you think I could get away with putting it in the dirt???
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WB2WIK
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« Reply #1 on: May 24, 2002, 11:26:09 AM »

Assuming you're not kidding, of course you still need concrete.

As the tower starts sinking into the ground, which is guaranteed to occur, and will continue to occur forever, especially after every rainfall, the tower will try to pull the side of your house along with it.

Rule of thumb for a 55' tower is a 36" x 36" square and 72" deep concrete foundation for an embedded (installed in the concrete) tower base intended to support the tower.  That's 2 cubic yards, which is pretty much the minimum for a 55' tower per virtually all the tower manufacturers' engineering specifications, as well as the building codes of just about everywhere.

If you're so far out in the country that there are no building codes or zoning -- and this is still possible, many places in the U.S. -- then you can pretty much do whatever you want, but for safety's sake it's best to follow the tower manufacturers' recommendations.

WB2WIK/6
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W8JJW
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« Reply #2 on: May 24, 2002, 11:43:24 AM »

You didn't say if this tower is self-supporting, or if it needs guyed, either way, you definetly need the weight at the base and the mass of the concrete.

If the tower IS self-supporting, if you attach it to the house, it will fail at the attach point. Self-supporting towers are meant to flex from the base upward, so attaching at a point up the tower causes all the strain to be focused there. Concrete is even more important in a self-suporting configuration.

Don't go cheap, don't forget to ground.

Good Luck
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WB2WIK
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« Reply #3 on: May 24, 2002, 12:11:27 PM »

Comment: There's nothing expensive about a concrete foundation for a tower.  New towers are sold complete with the base for installation in a concrete footing; used towers are often missing the base, since it was left behind in the concrete block of the previous owner!  However, the bases can usually be purchased separately and inexpensively, and if not, can be fabricated by almost any welding shop, if you provide them with proper dimensions.

Digging a hole can cost as little as zero, if you do it yourself; and concrete is very inexpensive.  The "mix" from the local cement yard is usually about $4 per 150 lbs, of which $1.50 is for the portland and the remains are for sand and gravel.  It takes about 26 buckets of mix, at 150 lbs per bucket, to fill a 2 yard hole.  That's just over $100.

Obviously, I speak from a lot more experience in doing this than I ever cared to have!  But I've moved a lot, and installed a tower everywhere I've ever lived, so can almost do it in my sleep, now...

WB2WIK/6
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K9KJM
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« Reply #4 on: May 25, 2002, 02:58:39 AM »

Rohn made a "drive-in tower base kit" years ago for the Rohn 20 series.... Mid 1970's  Was three, 3 foot long rods driven thru a steel plate to place the tower on. Then a house bracket as high as possible. I helped install several while working for a TV repair shop......... Very poor idea.....  I don't think any of them are still standing. In this part of the country, The ground freezing/heaving will rip the house bracket right off the house in a few years....   Minimum concrete is 3 feet, by 3 feet, by 3 feet deep. Bigger, deeper is better. Best/cheapest way to get the concrete is to have the tower in place and all set, and buy "leftover" concrete from some bigger job. When the big concrete trucks do a big pour, the "extra" in the drum is pretty much waste, and can be had for a great price in most cases. Downside is you have to be ready whenever they come by with the leftover concrete.  
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K8JSL
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« Reply #5 on: June 14, 2002, 11:28:48 PM »

I agree with all the suggestions above...
Let me interject my brief "been there done that"...

I installed my 70 footer, poured a  6x6x7 foot concrete base, my neighbor thought I was nuts.
His tower a 40 footer was installed just in the ground no concrete.
Well late last summer we had a real wing banger of a thunderstorm hale, wind, rain, you name it we had it.

Well the next morning guess who's tower was standing and guess who's came crashing down !!!! Complete with siding from the side of his house.....

Another thing to consider, most homeowners policy WILL NOT cover damages from a improperly installed tower !!! (his didn't)

Jeff K8JSL
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WA9ZOH
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« Reply #6 on: September 01, 2002, 04:15:13 AM »

I was successful for 4 years, with a Rohn 56 in the ground behind our garage. The reason I placed it into the ground was I was unsure if the village noticed it, they may require me to take it down. So, it was actually a test, however the " Test" lasted for 4 years then I moved and of course now have it in cement. How I did it was, I bought the 3 4ft. stubs that go in concrete, dug a 4ft. hole, put the stubs on the tower, lowered it into the hole. Then I put 3 2ft. lengths of 2x4 onto each leg that was above the hole, to prevent as much sinking as possible, filled the hole with sand and dirt. Then bought turnbuckles and 3/8in. plastic coated steel cable, and attached the 2 cables with the turnbuckles to each top side of the first section of the tower. Placed a level against the tower, and tightened until the tower was straight vertically. Approximately once a month, I would go back outside to the rear of the garage and retighten and check the tower with a level to make sure it was still vertical as possible. Incidently, I bolted the other side of the two cables, one to each corner of the garage via the garage supporting 2x4's. I climbed it many times and it was totally secure. It withstood winds of 56mph. The trick is to make sure the tower stays perfectly vertical. I feel I could have left it that way for perhaps 10yrs. One just must use alot of common sense in insuring its integrety.
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