Re: [TowerTalk] Rohn 25g unguyed height

[Grant Saviers <grants2@pacbell.net>]

I've done it with 3 25G sections bracketed at 15' and 8' exposed mast 
with a TH7DX at the top and it and house survived a couple of edge of 
hurricane blows, probably 80mph gusts.  Yes, unguyed 25G is wobbly stuff 
even when bolted correctly.
A potential big issue is the gable end of a roof that typically the 
bracket attaches to is not a structural element of a house.  It mostly 
is there to close up the end for weather. The rafters and joists handle 
the structural loads on the roof.  The gable end 2 by studs are toe 
nailed top and bottom so it doesn't take much pull them out.  Some 
backyard engineering I did was to brace across 5 studs with lagged 
double 2x8's and then use 2x angle steel to 4x8 3/4 plywood nailed to 
the attic joists. All thread thru to the bracing from the bracket.  
Several staggered 4x8 sheets shear wall nailed to joists to make a local 
structural membrane to pass the load to the actual house structure (a 
full floor is much better). Adding screwed Simpson ties top and bottom 
of the gable studs would also be a good idea.  If  attaching a bracket 
to a gable with finished interior space it gets ugly, or just luck 
without reinforcement, since most framers use the fewest nails they can 
get away with.
Grant KZ1W

On 10/24/2017 5:15 AM, Ed Sawyer wrote:
> I personally never climb, erect, nor recommend house bracketed Rohn 25G.
> It's a disaster waiting to happen.  I agree with the comment that if you
> have to do it, make the last  section the one that is bracketed.
>
>   
>
> Why not change the question around if you have room for a reasonable base?
> What kind of self supporting tower can I install next to my house?  Pour a
> nice base to spec and let the pre-engineered self supporting tower do the
> work like its designed to be.  Instead of dangerously at 27 ft you could be
> safely at 30 - 50 ft.
>
>   
>
> Even Rohn 45G has a 30 ft self supporting spec with a properly poured 45G
> base section and reinforced base pad.
>
>   
>
> 73
>
>   
>
> Ed  N1UR
>
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