Community Forums

Sky_Boss · 08-31-2015, 05:14 PM

I have to move my sat dish for an upgrade. I'm using the same base but the the new configuration causes it to lay down on top of my AC shrouded. I have a fiberglass roof.

The base plate was anchored down with 24 #12X3/4" metal screws. What I don't recall is whether there was any pre-drilling.

So...I'm looking for opinions on when I re-install the base.

1. Is it a good idea or even necessary to pre drill pilot holes? I've got both metal and self-drilling screws to choose from.

2. Is there a good reason to go with 1" screws instead of 3/4" or is that over kill?

okie143 · 08-31-2015, 08:05 PM

Quote:

Originally Posted by Sky_Boss

I have to move my sat dish for an upgrade. I'm using the same base but the the new configuration causes it to lay down on top of my AC shrouded. I have a fiberglass roof.

The base plate was anchored down with 24 #12X3/4" metal screws. What I don't recall is whether there was any pre-drilling.

So...I'm looking for opinions on when I re-install the base.

1. Is it a good idea or even necessary to pre drill pilot holes? I've got both metal and self-drilling screws to choose from.

2. Is there a good reason to go with 1" screws instead of 3/4" or is that over kill?

I took my ladder off my roof and it was put down with 8 #10x3/4" self drilling screws. They weren't stainless steel and they were rusted up, even thou Dicor covered them and they were water tight. I think it must be condensation from the screw.

My sat access hole has a plate on it and it has the same screws holding it down.

So I would use self drilling screws as long as you can ensure you are hitting the ceiling joists.

TQ60 · 09-01-2015, 07:46 AM

No on self drilling screws!

They drill hole for sheet metal and hole may be a bit large for tight fit.

Yes on pre drill but be careful to insure just through depth.

Wrap the bit with tape to make a depth stop.

Do use stainless steel and buy from a screw supplier or a mom and pop well stocked hardware store where they can provide a proper grade stainless screw as there are a few, with the proper head ( take your plate or measure the hole) and have them either measure the inner diameter of screw to determine drill size or better look up the proper drill size for use in fiberglass.

A good vendor can provide that.

To large of hole the screw has less grip and strength and too small it may crack.

Sky_Boss · 09-01-2015, 11:05 AM

Thanks so far!

I think the #10 size screws (roughly 3/16") are a pretty good fit for the base holes but 1/4" might be better. I will look into the stainless steel option.

I'm thinking that 1" shouldn't be too deep to get into anything below the roof. Does anyone think differently?

I figure I will tap up the drill bit and subtract about 1/8" to the screw tip has wood to bite into. Over thinking? LOL Being anal retentive sucks!

TQ60 · 09-01-2015, 11:55 AM

You are fine as questions are better than mistakes.

Get an extra bit or just use a coat hanger for wire and drill very lightly until either you go through or depth of screw whichever is LESS.

If you go through at 1/2 inch then active or full threaded part of screw should be that long at that point...remember the thickness of your bracket.

Take wire to probe through hole to confirm clearance and make sure nothing there.

Also consider making a pad or nest with decor or true rtv.

Test mount your device with only 2 screws to make sure all functions correct and fit.

Next drill all holes and then remove and clean roof and bottom of device.

Set back in place and pencil mark outline.

Place ducor or rtv or material of choice around all holes and the edges with a couple spots in the center.

Place device and insert all screws and tighten in star pattern until snug.

Wipe off oozing sealant and cover all screws and verify edges sealed.

The sealer keeps pad solid and acts like glue.

Again verify all good as once cured it will be solid mount.

Sky_Boss · 09-01-2015, 02:35 PM

Thanks Tony!

One thing I saw the installer do when it was first installed was to coat each screw with Dicor and put a dab of Dicor in each mounting plate hole before screwing them down.

After that he covered all screw heads with Dicor. I did notice that he did NOT seal the edges of the feet of the mounting plates. However, that seems to make sense because it would be difficult to coat all edges since some of them are obscured by the mounting plate.

I looked up my roof specs on my coach and they use 9mm (a tad over 1/3") decking under the standard BriteTEK that came with my coach. It was upgraded to fiberglass. Assuming the fiberglass is 1/8" I think a 3/4" screw is plenty long enough and will ensure I don't hit anything else below.

TQ60 · 09-01-2015, 07:16 PM

If you have wood under the glass then be certian you seal well as wood is a sponge and will soak in any possible moisture or vapor.

Packing holes should help.

To seal the edges by placing a bead of sealer on roof first thus the pencil line on the edge.

You make sure that any opening in part that rests on roof has sealer around the opening so water cannot wick under it to rust.

Using your finger or a stick to smooth out the sealer that oozes out should be all that is needed for caulking.

Dutch Star Don · 09-02-2015, 05:55 PM

Sky Boss.....You saw your installer do what I like to do, squirt either a good amount of Dicor or silicone into the hole first. This is just another layer of insulation in case water finds it's way around the screws.

Monaco really reinforced this for me when I changed out the running lights on my Diplomat. Monaco drilled about a 1/2" hole behind the running lights for the wiring to come through. Before they installed the light they squeezed a ball of silicone, about 1" in size into the hole and then installed the light. You literally had to cut out he silicone (larger than then opening) to access the wire. They never leaked.

I always cover as much as I can reach with Dicor, but be careful not to create any paths for water, if you can't seal an item entirely.

hawk57 · 09-06-2015, 09:43 PM

The F-16's (Air Force fighter planes for non-veterans) are held together with adhesives, replacing rivets. One mine, the original owner had aluminum diamond plate installed on the roof using the 3M emblem tape sold in commercial paint supply houses. This stuff is double stick that will not come off, even on long pieces like rub rails. You clean the perimeter of the housing plate and place the tape around the entire edges, leaving no gaps. Clean the roof with acetone and then carefully place the unit down and press evenly. The weight will provide the pressure and in about 10 minutes it cannot be removed. It is more expensive that Dicor and screws but it also is about triple or more times stronger. Fiberglass will never hold a screw and only invites leaks.