In a message dated 99-03-19 12:41:02 EST, you write:
> Do you bolt the tower feet directly to the roof
> or do you use any treated lumber on the outside
> to spread the load. The GME feet are about 1.5 in
> by 5.0 in. Roof tower articles in CQ use treated
> lumber on the outside to spread the load. GME says
> to bolt the feet right to the roof. If you bolt to the
> roof you minimize any trapped snow or water on the
> roof. Yes backing under the roof is always the way to go.
HI, Joe --
The way I look at it, we're trying to build a "roof sandwich" that we
can anchor the tower to; the middle 'meat' of the sandwich being the trusses.
Since the top of the roof already has a layer of plywood on top of the
trusses, we just need something 'under' the trusses. That's where the 2x4
backing plates come in. The plywood on top is good for leg compression loads
and the backing plates are needed for the tension loads.
Sometimes I use a 2x4 on the top but not always. My recommendation is to
go with the backing plate and not the 'direct bolt' method that GME suggests.
(This is a rare instance of violating the LXC Prime Directive by not 'doing
what the manufacturer says' but in this case improving their method.)
Cheers, Steve K7LXC
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