[TowerTalk] House bracket

[Bob Otto]

Hello David,

Depends on many things. First, you don't say how thick the board is
that you're attaching to the roof trusses.  That makes a big
difference.  Second, lag screws, holding wood with lag screws holding
the tower bracket is not the strongest method.  You're using screws
that are screwed into the ends of the trusses, which means they are in
the and grain of the wood. This means your combining the weakest
strength of the screw (the threads) with the weakest part of the wood
(the end grain) -- not much strength there.  It would be relatively
easy to pull the screws out.

The strongest situation you can have is to have the screw/wood joint
in shear.  This means you'd be better off to make a simple aluminum
bracket from 1/4" aluminum strap (easy to get at Home Depot) and drill
some holes in it for at least 1/4" lag screws to go through and into
the underside of the trusses, not the ends.  Bend the aluminum strap
so you can attach to to the tower legs using a U-clamp.  You will
never loose it, and you will have just a little give in the assembly
which will be good.  I hope this makes sense -- it's hard to put in
words what I could show you in ten seconds were I there.

You also do not say how tall the tower is and I don't recognize the
tower model number.  Hope that; A) your tower is a guyed tower, not
free standing, and B) that if it's more than another 10-15 feet over
the proposed bracket, you are also using guy wires.  A free standing
tower should NOT be attached to a solid object like your house -- the
result is you significantly weaken the structure.

73's from.......

Bob Otto
N8NGA@one.net
Cincinnati, Ohio

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Sunday, September 24, 2000, 9:44:06 PM, you wrote:


DL> Preparing to install US Tower MA550. Following manufacturers suggetion using
DL> a 18" x 18" by 18" base with a house bracket at about 19 feet. Planning to
DL> connect the house bracket by removing fascia and replacing with laminated
DL> green treated board, which I will lage screw into the ends of about 4 or 5
DL> roof trusses, then I will lag screw the bracket into this board...

DL> Does this seem like the right track? I don't want the tower to go over or
DL> wreck the house!
DL> Thanks Dave K0XH


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