Dish foot and lag bolts

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PopcornNMore

SatelliteGuys Pro
Original poster
Mar 20, 2005
3,635
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Gibsonia, PA
What is the correct length lag bolt to use on a FTA or DBS installation to your roofs eve? I have read 3", but shouldn't 2.5" be enough.

Also, how do most people mount the foot to the eve since on most eves the foot hangs off the bottom and a lag bolt can not be used since the bottom holes are exposed? I am thinking of using the top two holes plus possibly the center hole. Most often the center hole is hard to get to and the arm needs to be removed first.
 
At my last house I had the 18" dish mounted by just the two top bolts and while it never gave me any problems.... it didn't inspire much confidence either.

At my new place there was an existing Dish Network install. What the installer did here was affix a 1/4" or so aluminum plate to the eve and the dish bracket is attached to that. The Voom guy was impressed by it's sturdyness - lol.
 
I would make sure that the lag bolt has threads upto its hilt (so the entire length of the bolt). in terms of length....all you are penetrating is about 1/2 to 1" of material (shingles/sheeting). So if you use a 3" bolt, you really are not getting any more holding power than a 1 1/2" bolt. Also minimizes the chance of hitting a power source or plumbing, if it exists near the attic of your house.
 
I prefer fully threaded 1/4" or #14 hardened hex head sheet metal screws to weak SAE grade 2-3 lag screws. The hardened screws are at least grade 5. like the bolts used to assemble components in a car engine. Lag screws often break when power driven without pre-drilling. I use an impact driver and drive 3" lomgs screws, at least two of the center axis of the foot completely into the rafters or the studs of a wall. I will only mount to facia boards that at at least 1-1/2" thick, using 1-1/2" screws. If the bottom of the foot is below the edge of the wood, I still use four screws in the other holes, widely spaced, even if three is adequate. On a roof, 1-1/2" screws are fine for the corner screws that penetrate through the sheathing. In the case that I can reach the other end, where the screws penetrate in the attic, I will place 1/4"x1" fender washers and secure them with a 1/4" Palnut, which fits the screw threads perfectly. I use this method often on tripods, which almost never align with the rafters on a roof.

I've never had any dish or antenna work loose or come down. Overkill, maybe? But, I've never had to repair a roof or a dish or antenna blown loose. My customers are always satisfied, too.
 
Thank you all for your comments and suggestions.

I disassembled my DirecTV setup today (one of those FREE installations where they do 20+ installations a day and are at your house only 5 minutes). The installation was a mess and the ground wires were not even attached.

I used (2) 2.5" galvanized lag bolts at the top and (1) 3" galvanized lag bolt in the very center. This held the mount on very tight and level.

I replaced the 18" DirecTV dish with a new Phase III DirecTV dish (101, 110 and 119). I then installed the 18" dish pointing at Echostar 7 to get the Miami and other FTA channels. I also installed a Terk TV-42 UHF antenna for extra local channels and received a new Winegard 30" late this afternoon that I plan on installing tomorrow for additional FTA pointing it at Galaxy 10R.

I may even go ahead and install my SG2100 to this Winegard 30" dish and use my 1.2m Channel Master for strickly C-Band now that Cascade is having such great success. I will be posting pictures soon.
 
sounds good :)

I just went and got some 5/8 x 2 1/2" screws for my 36"...the bolts that came with it I wouldnt use for a 18...much less a 36 :D
 
I wasn't able to mount the new 30" Winegard onto the eve of my house along with the other dishes. The mast arm was too short and could not be mounted facing South. You would think the mast arm would be made longer on these 30" dishes.

I notice that some people mount their larger (30" +) dishes on the top of there roof instead of on the eve. I would be afraid to drill holes into the shingles and possibly causing the roof to leak.
 
PopcornNMore said:
I wasn't able to mount the new 30" Winegard onto the eve of my house along with the other dishes. The mast arm was too short and could not be mounted facing South. You would think the mast arm would be made longer on these 30" dishes.

I notice that some people mount their larger (30" +) dishes on the top of there roof instead of on the eve. I would be afraid to drill holes into the shingles and possibly causing the roof to leak.


Here is my take on proper roof mounting:

DBS ROOF INSTALL TECHNIQUE

I install a lot of roof mounts on pitched asphalt shingle roofs. I never never use silicone or roofing cement or coatings. And, I never use those lag screws that require predrilling.

I use #14(1/4"dia) fully threaded hardened hex head drive sheet metal screws. I drive two three inch long ones into the rafters and four 1-1/2" long ones into the corners of the feet. It is not difficult to find the rafters, since hitting the roof surface with the back of your fist will result in a solid sound. Even if you miss, six fully threaded screws will provide a very good hold that will require a hurricane or a tornado to blow off. In that case, the home owner's insurance will apply, since it will be considered an "Act of God."

The above provides for one solid mount. The screws driven through the shingles, without predrilling, provides a near perfect seal, since the heat generated in driving them melts the asphalt, which rehardens around the screw. This is also basically how roofing nails work. Just for insurance and for those customers who inspect the install, I cover the heads with a pliable modeling clay like duct seal. A one pound brick costs no more that $2 at Home Depot. This is also perfect for sealing cable wall entries.
The best level that I have used is the Israeli made Post-Rite sold at Sears for $5.99. It is a post level with two bubbles spaced 90 degrees apart on a vertical hinge. The magnets don't work that well, but the elastic strap holds it firmly on the "J" pole. It's worth having, if you do a lot of installs. Forget the bubble level that fits on the inside of the mast. It requires you to get up and increase your center of gravity to look at it from the top, which can be dangerous on a steeply pitched roof. With the Post-Rite, you can do everything while sitting on the roof's surface and still have access to see the levels, without moving your position above and back down to the mounting.
The center of the dish mounting foot is usually marked with an embossed line down the center. Except for a very old mounting foot, one of the center holes is round, and the other is a slotted arc. The first step is to screw in the long 2-1/2" to 3" long screw into the round hole, just driven down enough so that you can pivot the foot on this one screw. Swing the pole up and down and pivot the foot until both bubbles on the Post-Rite are centered. Drive in the second lomg screw. Then, drive in the short corner screws until snug. Using the bolts and nuts that hold the pole to the foot, tighten them for a final adjustment, if plumb had shifted a little due to the roof shingles having been compressed from driving in the screws. Use small balls of duct seal the size of a small marble and work them over the screw heads.
Set the skew or tilt and elevation correctly on the dish correctly for the locality. Place the dish back on the pole and tighten the vertical clamp bolts just tight enough to take up all of the wobble. Swing the dish horizontally until you get the highest signal level on the meter. Tighten the vertical sleeve mounting bolts. Check the TV to verify signals for each satellite position.
 
PopcornNMore said:
I wasn't able to mount the new 30" Winegard onto the eve of my house along with the other dishes. The mast arm was too short and could not be mounted facing South. You would think the mast arm would be made longer on these 30" dishes.

Ya, I noticed that too. I was thinking of transferring my 30" wineguard over to an expressvu dish mount just for that reason. I find the mount also tricky if you have to go below about 15 degrees on the vertical (so for those in northern canada)..To say the least I wasn't impressed with the whole thing.

I notice that some people mount their larger (30" +) dishes on the top of there roof instead of on the eve. I would be afraid to drill holes into the shingles and possibly causing the roof to leak.
Just use some good rof flashing caulk around the holes etc.. NO LEAKS
 
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