Vinyl siding

Jeff Eastman · 10-13-2007, 07:34 AM

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**Jerry Peck** · 10-13-2007, 08:01 AM

What kind of "cable"?

**Jerry Peck** · 10-13-2007, 08:22 AM

I doubt that TV cable is going to hurt anything, but I think that the vinyl siding is supposed to be at least 2" above the roof covering - like all siding should be.

**Stuart Brooks** · 10-14-2007, 02:54 PM

Originally Posted by Jerry Peck

I doubt that TV cable is going to hurt anything, but I think that the vinyl siding is supposed to be at least 2" above the roof covering - like all siding should be.

Is this a "C" spec or a building practices issue? I'm thinking a "practices" because I haven't seen any gaps in this neck of the woods. I agree that the J-channel (or siding as applies) should be above the surface of the roof. At least high enough to verify installation and condition of the flashing. I've had one house with cedar siding that was run right down to the roof at all intersecting planes. Maybe somebody decided that the no-gap installation was pretty or was an installation goof. But homebuyers liked the pretty look and demand drives the market.

Last inspection was in a new subdivision where every house had vinyl siding that was run to the intersecting roof surface. The ends were not even in J-channel. Installer ignorance or developer was super cheap? It will be interesting to see how much of it is ripped off when a big wind comes through from the right direction.

**Jerry Peck** · 10-14-2007, 05:32 PM

Originally Posted by Stuart Brooks

Is this a "C" spec or a building practices issue?

I think I remember seeing it in the ARMA Manual, which I had but cannot find right now????

The reasons are several: a) installing the 'J' channel down there now nails through the flashing down close to the roof, and the Flashing should be at least 5" high, and nailed along the top near the top edge - not down near the roof - or; b) not nailed to the wall at all to allow for differential movement between the roof and the wall; c) to allow for the roof to be re-roofed without having the 'J' channel in the way.

**Stuart Brooks** · 10-15-2007, 08:27 AM

Thanks Jerry. I'll do some research in siding and roofing manufacturers and associations.

**Bob Mulloy** · 10-16-2007, 04:21 PM

Stuart,

Jerry was right on the money with his answer, but I have one addition. The channel is also not supposed to be in contact with the roof covering as the heat can damage the vinyl channel.
Visit the vinyl institute and download their manual free.

Bob

Richard Rushing · 10-16-2007, 05:29 PM

Bob has it right. The J-channel has to be atleast 1/2" inch off the roof line.

rr

**Stuart Brooks** · 10-17-2007, 07:21 AM

The Installation Manual form the Vinyl Siding Institute: I can't find anything about roof line clearance. In fact, their installation diagram implies it is placed on the surface.

However,
The installation manual from Certainteed does recommend 3/4" to 1" clearance between the J-channel and the roof surface but does not Specify any clearance.

Section 4 - Preparation for Horizontal Siding
Installing trim at roof line

To prevent water infiltration along the intersection of roof and
wall, install flashing before installing J-channel. At points
where vinyl siding and accessories will meet at a roof line –
such as areas where a gable dormer or a second story side
wall intersect with the roof – it’s best to position the J-channel
so it’s 3/4" to 1" away from the roof line. Placing the J-channel
directly on the roof line would subject it to a build-up of heat,
which could result in excessive expansion.

NOTE:
If you use more than one length of J-channel to

span a wall surface, be sure to overlap them 3/4".

Not happy about that. Unless there is a local requirement about the only thing that be said is that it may cause excessive expansion in hot weather, which in turn, may cause the siding to buckle.

Stu

**Jerry Peck** · 10-17-2007, 07:37 AM

Originally Posted by Stuart Brooks

The installation manual from Certainteed does recommend 3/4" to 1" clearance between the J-channel and the roof surface but does not Specify any clearance.

Actually, that DOES "Specify" a clearance of 3/4" to 1".

It just does not *require* it.

Common sense, and their instructions, *require* it.

**Stuart Brooks** · 10-17-2007, 07:42 AM

Just looked at Alcoa's manual. It says 1/2" clearance.
Stu

**Stuart Brooks** · 10-17-2007, 08:02 AM

My mistake - Vinyl Siding Institute does has a paragraph covering intersection at roof line as included below:

J-Channel Over Roof Lines

Install the flashing before the J-channel to prevent water infiltration along the intersection of a roof and wall.

■

Keep the J-channel approximately 1/2" from the roof line. Chalk a straight line up the roof flashing to guide J-channel installation. Tip: You can use another J-channel laid over the shingles as a spacer to create the straight line desired.

■

Overlap the J-channel (lapping the upper piece over the lower piece) if it is necessary to use more than one piece.

Extend the J-channel past the edge of the roof, channeling water into the gutter, in order to ensure proper runoff.

■

With dark shingles, or a south or west exposure, it is recommended to either use a metal J-channel or to install the vinyl J-channel as far away from the roofing as is aesthetically acceptable, having first ensured that there is sufficient flashing behind the J-channel to prevent water infiltration.

NOTE: Vinyl J-channels should not be in direct contact with roofing shingles, since the shingles may transfer enough heat to the vinyl J-channel to cause its distortion