[TowerTalk] unguyed with house bracket

[David Calder]

I sure wouldn't try it. I don't even trust the fascia board as has been said
here. I also
don't trust the side of the house. Both mine are bolted thru the roof.

If your going to try it on a mobile home, make sure it's done where the roof
meets the wall
at the top corner. That's probably the stoutest spot.

IMHO

Dave
n4zkf
 

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of AD5VJ Bob
Sent: Thursday, November 15, 2007 8:50 PM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] unguyed with house bracket

No one has answered my question about the Mobile home

Can you bracket to the V at the side of a mobile home or will the mobile
home hold it?

It is a rental and I have permission for antennas, but wouldn't want to pay
for a new wall or anything :)

tnx Bob AD5VJ 

> -----Original Message-----
> From: towertalk-bounces at contesting.com 
> [mailto:towertalk-bounces at contesting.com] On Behalf Of Jim Jarvis
> Sent: Thursday, November 15, 2007 1:58 PM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] unguyed with house bracket
> 
> 
> Lest the critical info be lost, there was a post which referred the 
> Uninitiated to a QST article on how to house-bracket correctly.
> 
> Fascia boards are trim, not structure.  You must tie into the 
> structure.
> 
> Using a 2x6 backing plate inside an attic sidewall  is preferred.
> But here's an alternative which has worked:
> 
> I did not have an attic, it was a flat-roofed house.  All I could do 
> Is lag screw into the roof joists  and the floor joists between the 
> first and second floors.  That gave me two points of attachment.
> 
> My 'bracket' was constructed of 2x8's, 5' long, which spanned
> 3 bays of Roof joists.  I used 1/2" x 12" lag screws into the
> 2x12 roof joists, Carefully locating their centers, and pre-drilling 
> pilot holes, so nothing split.  There were 2 bolts at each of the 3 
> joists I intersected.  Each bolt was rated for 2700 lbs extraction 
> force, and considerably more in shear.
> 
> The tower was captured by a sandwich of 2x6"s which were bolted to the 
> 2x8 backing beams in question.  So, I had the ability to withstand 
> something
> >12,000 lbs pullout, and 24,000 lbs shear failure at each of the two
> brackets.  
> 
> In turn, I calculated the windload with ice, from the antennas and 
> tower, and determined that at 90mph, it should be no more than around 
> 5,000 lbs at the point of the upper bracket.  With a more than 2x 
> safety margin, I felt reasonably comfortable.
> 
> Let me point out that there were critical measurements involved, and 
> that a borescope was used to look at each pilot hole...and that each 
> lag screw was installed, removed, the hole inspected for structure, 
> and reinstalled.
> You can't be casual about whether you've hit the beam or not, in that 
> situation.
> 
> And NO, you can't rely on a double-wide at 10' to hold up a tower at 
> 40', with any kind of wind.  You don't have the overbuilt structure 
> that is common with site-built houses.
> 
> n2ea
> 
> 
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> 
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