Roof Nailing

[D725A]

We hope to have a new architectural roof put up on a 1924 colonial with 1x7 tongue and groove decking. Most of the wood has held up very well for the 88 years, a few cracked pieces we can replace with extra same-size pieces from the attic floor.

Opinions from roofers vary; obviously there will have to nails coming through the decking between the roof joists. The question is where to avoid having the nails come through. Obviously hitting it through the edges where the tongue and groove is is not a great place. And if it's dead center of the decking section between the rafters there's risk of splitting the wood. One roofer told me since they know the width of each piece and the location of the joists below they can mark out some kind of template for the underlayment and shingles so they'll always know about where they are.

Does this sound right? Perhaps with the new nail guns there's less hammering overall and less stress on the wood?

 

[joecaption]

Sounds like he's blowing smoke.
Once the papers over the roof there not going to know where the seams are.
Your over thinking this whole thing, roofers have been installing shingles over old roofs like that for hundreds of years without any problums.
The nails almost always stick through the roof decking a small amount and has no effect on it.

 

[nealtw]

If he intends to only nail every 16 or 24 inches get another guy. It's alrite to ask silly questions, it's a whole different thing to get dumb answers. His answer should have beem more like what Joe said.

 

[D725A]

Thanks Joe and Neal. So what is the proper approximate spacing for architectural asphalt shingles?

(Actually my original question arose after a roofer told me that a piece of the decking had been cracked by a roofer hitting it in the wrong place--too close to the weakest part of the 1x 7 board....This had never occurred to me.)

Another roofer told me he never puts a drip edge where the gutters are, only on the gable edges of the roof. That was a new one on me. Luckily for consumers these days we have the internet and websites like these where we can get straight answers. Even if there's differing opinions at times, we can educate ourselves enough to help ensure the job is done right.

 

[joecaption]

4 nails per shingle unless it's a high wind area then it's 6.
I would never not use drip cap around the whole roof.

I guess he forgot water runs down hill and that one area is going to see more water then the whole rest of the roof.
If someone said that to me I would have walked back in the house not even saying good bye, not worth my time taking to him.
There is no wrong area to nail a 1 X 6. If one broke most likly it was there was a big knot in that area.

 

[D725A]

I just went over the contract with a roofer I hope to go with. A few things came up:

1. He generally uses nail guns and claims that there have been great advances in controlling the pressure so that shooting nailheads through the shingle is not an issue.

2- Says they usually don't add drip edge on the rakes --especially if there's vinyl siding already with nice-looking trim that might not look as good with a drip-edge added. (see attached photo.)

3- He generally uses LionGuard ice & water shield; I prefer the Grace product. Any thoughts on LionGuard?

 

[oldognewtrick]

We never put drip edge on rake edges with fascia wrap that has a shingle molding built in. It extends the drip edge to far out from the fascia. More important is using a starter shingle up the rake edge. Not a 3-tab shingle flipped around but a dedicated starter with a seal strip on the outside edge. Over hang past the drip edge is 1/2". To much and the shingles will droop and crack over time.

Nail placement is CRITICAL. There is a 5/8" nail line on a dimensional shingle. Nail to high and you miss the laminate strip, if you see sliding parts of the shingles after they age, it's because they didn't follow installaion directions. Nail to low and you will see the nail heads.

 

[D725A]

Ok so after almost two months of interruptions for other house projects, we found what looks like an excellent roofing company. He looked at the underside of the sheathing, saw many gaps in the tongue and groove and said they might have to re-sheathe with plywood. I guess such gaps weaken the roof a bit--he pushed on it a bit and it had a bit of play. See photo. Any thoughts on this?

In addition i am continually amazed at the disparity of opinion amongst experienced professionals. Some roofers have said the ice and water shield can obviate the need for a drip edge, even on the eaves. All the internet info I've seen suggests a drip edge is a relatively inexpensive protection against water from wicking back under the shingles, so it will run cleanly off the edge. and that the back of the gutter should go behind the drip edge to prevent water from going between the gutter and fascia. I guess with ice shield even if the water does run back under the shingles it won't penetrate, but still....

 

[nealtw]

The tongue and grove was put up wet and then dried a little small, unless you have rot or damage, nothing has changed for 87 years.

 

[joecaption]

I still install drip cap even if there's shingle moulding for several reasons.
Plywood, or in fact any wood soaks up water mostly through the exposted end grain.
If there's a strong wind blowing towards the gables on a roof, water can get into the end grain and get in between the coil stock and 1 X 6's forming the rake.
It helps to hold the coil stock flat to the fashia with less nails.
The little curl on the face of it helps to let the drips, drop just enough away from the fashia to have less black streaks on the face of it.
To me it's just cheap insurance and worth the little extra cost.

 

[PaulPeterson]

We hope to have a new architectural roof put up on a 1924 colonial with 1x7 tongue and groove decking. Most of the wood has held up very well for the 88 years, a few cracked pieces we can replace with extra same-size pieces from the attic floor.

Opinions from roofers vary; obviously there will have to nails coming through the decking between the roof joists. The question is where to avoid having the nails come through. Obviously hitting it through the edges where the tongue and groove is is not a great place. And if it's dead center of the decking section between the rafters there's risk of splitting the wood. One roofer told me since they know the width of each piece and the location of the joists below they can mark out some kind of template for the underlayment and shingles so they'll always know about where they are.

Does this sound right? Perhaps with the new nail guns there's less hammering overall and less stress on the wood?

If you are using a nail gun then it will have less to zero chance of nails coming through...

 

[joecaption]

Not likly in real life any roofer is going to come up with some template to avoid the joints.
If your that concerd with it just go over the whole roof with 1/2 CDX plywood or OSB. It's done that way all the time.

 

[D725A]

Just to resolve this thread, the roof has now been completed. While there were some other issues I won't go into here, the nailing seemed to work out well. They used 1.25" nails with nail gun; some of the old planks have knot-holes and cracks, but overall looks sturdy. We had the option of half-inch CDX plywood but felt the old boards would work out fine.