roof mounting a 33" dish

[TiminMb]

I am roof mounting a Digiwave 33" dish. The roof is the only point of height sufficient to clear neighbouring homes to the south. My concern is ensuring the mount will hold up to weather conditions, strong winds. The dish came with a mount having a relatively small base and additional struts for support. I mounted it all to the northern slope of the roof using 6 lag screws. I'm concerned this might not be sufficiently strong. Should I trust it? Or should I fabricate more struts from the mast to spread out the force over a longer area?

 

[Van]

If you planted the two strut lags into roof studs thats a good start but you should also have two center lags into the foot plate that would go into roof studs also.

 

[TiminMb]

How do you locate the roof studs?

 

[Mike500]

How do you locate the roof studs?

A lot depends on whether is you can access the place in the attic under the roof deck at the place where you plan to mount the dish.

If you can, you can reinforce the roof with 3 inch deck screws and pieces of 2x6's or 2x8's between the rafters at the locaion of the mounting foot and the struts. You can easily find out how far dowm the roof the location is by locating a plumbing vent that penetrates the roof into the attic. Outside, locate the row of shingles at which the vent is mounted which is above your desired mounting foot location. Measure the distances from the vent pipe to a spot directly above the mounting spot and the distance dowm the slope of the roof. In the attic, transfer those measurements to the spot under the roof deck. This is where you'd locate the 2x6's or 2x8's. In this method, you can use carriage bolts to mount the dish foot and the struts. This method is the strongest.

If you do not have access to the underside of the yoof, there are several ways to locate the rafters. If the rafters are exposed under the roof, as in Florida or the Southwest, it is a simple matter of flowwing them up the roof. If you do not have a metal drip angle under the bottom edge of the roof shingles, you can lift them up and you may see the ends of the rafters or, as they are called, the rafter tails. If you have ridge vents, you may be able to pry up the edge and find the rafters there. At the very spot you can usually hit the surface of the shingles with a rubber mallet and recognize a solid sound as compared to a hollow sound. A solid sound woud represent a rafter.

I would not use lag screws, as they are weak SAE grade 2 fasteners. I'd use harden screws like the Simpson Strong Tie that are available in 3 and 1-1/2 inch lengths at Home Depot. These can be driven with a cordless drill directly into the wood without drillling for the greatest holding strength. They are at least Grade 5 or higher and will not shear off. As a professional installer, I usually use an impact driver with great success.

 

[TiminMb]

Thanks for the advice. You were right, I can find the studs by pounding on the roof, its quite clear when I am over a rafter.

I used some 3/4" steel tubing and fabricated two more struts, long enough to reach the adjacent rafters. Still have to make a trip to Home Depot and look for those screws you recommend. I want this mast strong and stable. I'd hate to have to climb the roof in the winter to do repairs.

 

[drhydro]

Timinmb,
Make sure to use plenty of roof caulking, you dont want any leaks I would seal around anywhere you penetrated the shingles.

 

[Mr Tony]

moved to FTA area

 

[TiminMb]

Bolted it down with the two additional struts to the rafters. Its not going anywhere unless you rip the roof off the house. Bad news, its not perfectly level. The pole leans ever so slightly to the west. I may have to put some shims under that side. I take it that it is critical to level this to perfection, as in having the bubble exactly centred on a level. Or is there any way to fudge this with the mounting of the SG2100 motor to the pole?

 

[PSB]

Get it as close as you possibly can time spent here may save you days of headaches. The bubble has to be level, in fact I off-set the bubble to take into account the weight of the dish and motor. Come winter you will be happy you done it right!

Its that important!

 

[Mr Tony]

Come winter you will be happy you done it right!

and looking at Tim's location, he won't want to be out inwinter working on his dish
(I'm in MN so I try not to work on my dish in the winter unless its necessary)