Thread: Telegraphing Shingles In New Construction

ok….I am trying to figure out what is causing or caused telegraphing of my roof on my new construction home. Roof was framed in early September, 2014. H-Clips were used with OSB plywood (I believe 5/8") was used - Tech Shield by LP with OSB Face UP (foil facing the attic). Laid on 24" OC Trusses used with with spacing. Prior to shingle installation My roofer inspected and all barge rafters were installed along with proper spacing (1/8") . We had a few mornings with 20 degrees or cooler here in the Carolinas recently and this is when we started to notice the telegraphing. I would say that the roof was fully dried in with shingles and felt paper by mid-september. The interesting part is that no telegraphing is taking place over the garage- this is, however, the only insulated roof in the house at this point (used open cell spray foam I believe) with baffles used so it was not sprayed directly onto Tech Shield - providing at least 1" or more space. Where the main house is there is and where the main telegraphing is taking pace no insulation above the drywall ceiling yet - this is all a one story home with just open roof/attic system.

I have read the following can be the concern:

1. Trusses contracting due to cold weather
2. 1/8" spacing was violated even though H-Clips were used
3. Framers standing on OSB while nailing in

My questions are the following:

1. Is there anyway to correct this without tearing off roof? Another builder friend suggested adding some bracing to the existing truss system to try and level out the truss system? I may have this incorrect

2. IN the spring and summer months will the added humidity bring this back to normal coupled with roof singles laying down better ?

3. AM I just OCD and should not worry about this and just live with it?

4. Could this be an issue with the Tech Shield itself? Warranty issued?

Attached are pics….

Originally Posted by Armybanker

... this is, however, the only insulated roof in the house at this point (used open cell spray foam I believe) directly against the tech shield with cardboard baffles providing at least 1" or more space. Where the main house is there is no insulation above the drywall - this is all a one story home with just open roof/attic system.

For clarity - spray foam insulation against the underside of the roof sheathing ... got that, but ... then you said cardboard baffles providing 1" or more space ... ????

The cardboard baffles are where and are providing 1" or more space where?

When the insulation is spray foam against the underside of the roof sheathing the attic should be sealed, not vented - the cardboard baffles and 1" or more air space indicates that attic is vented?

Looks pretty typical for a truss framing system. Almost every truss roof home I see looks similar if not more pronounced. Chances are if you had it completely redone it would be the same if not worse.

Originally Posted by Scott Patterson

Looks pretty typical for a truss framing system. Almost every truss roof home I see looks similar if not more pronounced. Chances are if you had it completely redone it would be the same if not worse.

99% (or so) of houses built in Florida in the last 40 years use engineered trusses ... and probably less than 1% look like that (guessing on the less than 1%).

Don't blame that on the trusses, that is caused by the roof sheathing, not the trusses.

The same contractors installing roof sheathing on trusses and getting that will have the very same problem installing roof sheathing on conventional framed rafters.

The only thing that will eliminate that is for those contractors to go back to using board sheathing instead of structural panels ... it shows with structural panels because the panels are 4' x 8' and the edges show, put 1x6s in their hands and you wouldn't see the board edges the same way because every 5-1/2" would be a joint going up the roof, and the boards would probably be 12' long with staggered joints, so you wouldn't see a 4' straight line like structural panels will show.

Don't blame that on the trusses.

I may have mis-stated ...the spray foam insulation is over the garage / bonus are where there is no sign of this issue. Where you see the issue is over the main home where there is no insulation In the attic yet

Do I have any recourse wit LP tech shied?

Originally Posted by Jerry Peck

99% (or so) of houses built in Florida in the last 40 years use engineered trusses ... and probably less than 1% look like that (guessing on the less than 1%).

Don't blame that on the trusses, that is caused by the roof sheathing, not the trusses.

The same contractors installing roof sheathing on trusses and getting that will have the very same problem installing roof sheathing on conventional framed rafters.

The only thing that will eliminate that is for those contractors to go back to using board sheathing instead of structural panels ... it shows with structural panels because the panels are 4' x 8' and the edges show, put 1x6s in their hands and you wouldn't see the board edges the same way because every 5-1/2" would be a joint going up the roof, and the boards would probably be 12' long with staggered joints, so you wouldn't see a 4' straight line like structural panels will show.

Don't blame that on the trusses.

Looks like no spacing at the ends of the OSB. Also could be improper nailing (nails missed the trusses). Another possible cause could be swelling of the OSB at ends, but that is unlikely.

When you install spray foam in an attic to the bottom of the decking a 1" ventilated air gap must be installed between the roof deck and the insulation for warranty purposes. The manufactures' are concerned with the heat build up damaging the shingles.

Originally Posted by Mark Reinmiller

Looks like no spacing at the ends of the OSB. Also could be improper nailing (nails missed the trusses). Another possible cause could be swelling of the OSB at ends, but that is unlikely.

A) "Looks like no spacing at the ends of the OSB."

B) "Another possible cause could be swelling of the OSB at ends,

A) causes B). (When the two sheets of OSB close the gap and what was the gap now becomes the proverbial "Between a rock and a hard place" and the two ends crush each other and swell up (okay, maybe "swell up" is not a proper descriptive word, maybe "crush up" but when something "crushes up" it is usually thought of as getting 'smaller', not bigger).

B) is also caused when the OSB ends get wet long enough or often enough and the water swells up the wood fibers.