Roof deck seems


#1

What causes the roof decking seems to be obviously visible after the asphalt shingles have been installed?

Specifically, I have seen numerous roofs where you can clearly see the vertical seem of the 8 x 4 roof decking. Maybe there is not anything strucually wrong with this but cosmetically it looks like crap!

What can be to avoid this? :?


#2

I believe that it is slight moisture getting to the seam,this can’t be avoided. I have also found that a good underlayment like Gaf. Shingle Mate paper helps hide it. Roofs that looked that way before replacement now look great…Also helps to use Arch. shingles…The Shingle Mate paper is about 2x the price of a generic 15 lb. felt,but it is worth it to have a nice flat surface to shingle over…
Be careful though,once you use it you can’t go back,lol…


#3

Can also be not enough venting.


#4

the only vertical thing i can think of is seein a rafter through the shingles.
ditto jwoolf to fix.

gweedo.


#5

I have seen whole developments in my area that all the houses are new, and you can see the (plywood) seams right through the 3 tabs…May be that the house sat too long before it was roofed…


#6

plywood needs an 1/8th in gap at the seams…maybe they are buckeled.

Maybe they have popped loose because they werent installed with Ring shank nails. Thats what i usually see happen.


#7

[quote=“marshall exteriors”]plywood needs an 1/8th in gap at the seams…maybe they are buckeled.

Maybe they have popped loose because they werent installed with Ring shank nails. Thats what i usually see happen.[/quote]

In my experience that is usually the cause.
30# felt will hide it even better, after you renail the deck…


#8

then the 3tabs must be shingled rite over the plywood.
hmm?
wouldnt that be a surprise.
surprise indeed.

gweedo.


#9

[quote=“gweedo”]then the 3tabs must be shingled rite over the plywood.
hmm?
wouldnt that be a surprise.
surprise indeed.

gweedo.[/quote]

You lost me there Gweedo.


#10

[quote=“Steve77”]What causes the roof decking seems to be obviously visible after the asphalt shingles have been installed?
[/quote]

  1. It’s a 3-tab thing. You would never see it with architects.
    Three-tabs show every imperfection on the deck.
    I am not saying i dont like three-tabs.
    I absolutely insist on it with certain pitches.

  2. Its a morning thing. and when you view it from a certain angle.
    Look again in the afternoon. You mostly wont see it.


#11

Roof Lover, Why do you insist on 3 tabs with certain pitches?
I agree that architects hide most of it.


#12

If your house is insulated with foam you will be able to see the where the rafters are when it is cold.

This is because foam is such a good insulator that the wood lets through more heat than the insulation does.
Not a bad problem to have…


#13

There is this Builder that used T&G Avantech for roof decking on a couple houses. Following year you can count sheets from the road. The bottom side of the decking gets a lot of moisture/ heat on its way to the ridge vent.
The 1/8" spacing is needed to prevent this. I roofed these homes and the deck was solid, but if I get he re roofs I will recommend a saw kerf to ease the expansion and contraction sheathing requires.
Oh, It was a one year deal and we are back to the 5/8" plywood.


#14

[quote=“shangle nailer”]Roof Lover, Why do you insist on 3 tabs with certain pitches?
[/quote]

Those straight lines you see when you install a
6 inch bond line are called water lines.
They help guide the water down the roof.
This is important on a low-slope roof.
The lines help move the water off the roof instead of going up under your shingles and rusting out the nail heads and entering your side butts.

Architects actually hold water on a low pitch roof.
Water will sit on top of the nailing area, rusting them out. The shingles and their fasteners start failing left and right about right when the workmanship warranty is up. Or right away after a big storm if the pitch is really low.


#15

will you put architects on a 4? I’ve done a 2.5 before, with water and ice all the way of course. I guess I don’t see how it can happen without ice dams. The singles are sealed right?


#16

Yes, but only if Honest to God every nail is where it is supposed to be in the double laminate 3/4 inch area.

But, most roofers do not have the skill or the caring to achieve this. So in this case where i might be leading a crew for another license holder where everyone is not a complete anal perfectionist, my recommended minimum pitch would be a 5/12.

The roofers can be as sloppy as they care to be and it will be OK on a 5/12 and above and it wont leak.
But once the pitch reaches 7/12 or above, their sloppy nailing causes some shingles to eventually fall out.
Especially Elks…

If i am leading the crew where my state license and name is on the line, only the anal perfectionist are allowed on the roof. So 4/12s.

3/12s? completely out of the question.
3-tabs with two-ply (19 inch laps)underlayment
or standing seam metal roof.
There are 3-tabs out there that mimic the look of an architect and cost the same as architects and these are the ones that i try to lean the homeowner to.

I use a 4 foot level and a johnson pitch gauge on the roof before i decide what to do with it.

And no, you couldn’t out guess me on a roofs pitch.


#17

really nice to see someone understanding
water flow and the importance of the 3tab shingles.
very nice roof-lover.

you know your fla roofing.

impressive.

AX,
sorry i lost ya , i was just sayin that maybe the
3tabs were layed directly over plywood, and thats why there seein theese plywood lines.

gweedo.