I mounted a several hundred pound satellite array on my roof
and the system was in place for over a decade with no leak
The array sat on a 5-ft X 8-ft angle-iron frame. The frame was
intended to spread the load out over a substantial area of the
3/4" plywood roof. The frame was supported about 8" above
the roof shingles by four long 3/4" galvanized/threaded rods
along each 8-ft side of the frame.
First, a pair of 2X6 boards were placed inside the roof running
along the underside of the roof trusses under the sides of the
angle-iron frame. These stiffening boards were screwed into the
trusses with several deck-screws at each contact point.
Holes for the 3/4" threaded rods were drilled through the roof
and through the 2X6 support boards. The shingles around each
rod-hole were peeled back and the rods inserted. A large washer
was held in place against the underside of the roof with a nut.
On the top side of the roof around each rod, a very generous layer
of thick roofing/flashing RTV polymer was put down in a 6" or 8"
diameter patch. This is the type of black roofing/flashing goo that
cures to a hardness about equal to the rubber in a car tire but
has enough stretch not to crack when flexed or stretched a little.
After curing, a large washer was placed on top of the black RTV
and firmly held in place with a nut. The nut and washer were then
covered with a generous coating of RTV. Finally, a flanged sealing
boot was placed over each bar and VERY thoroughly sealed with
more Black RTV goo. A final layer of black-roofing paper was
placed around each flanged sealing boot and then the shingles were
This support for my satellite antenna array was in place for about
12 years with not the first sign of any leaking. Periodically, I would
crawl up inside the roof after some hard rains and check for leakage
but never found any. Eventually I gave up checking after every hard
rain and only made a leak-check once or twice a year or after some
particularly high winds during a storm.
While I did all of the installation after conferring with a well-known
roofer here in town, he did tell me that any competent, experienced
roofer could do this.
When we moved, everything was removed and the penetrating holes
were patched up with more of the black RTV roofing goo and new
shingles laid down over everything.
Mike Baker WA4HFR
Gainesville/ Micanopy, FL USA
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