FJP cedar lap siding nailing instructions

[BigLou80]

Our customer wants us to use FJP cedar lap siding, we tried to talk him out of it but what ever that's not what this is about.

The instructions call for ( and have for a few years) the nail to be set high enough in the plank that you DO NOT nail through the top of the piece below. I don't like this method of nailing as it seems likely to cause the board to split, makes the nail quite a ways in to the middle of the board and only leaves one row of nails holding each piece on. It also is against every siding installation I have ever taken apart, the oldest being 1710's era.

I plan on calling the manufacturer to ask why, but I was wondering if anybody here has any reason why they wouldn't want you to nail through both planks at once. I have never seen a normal installation fail

[Chuck Kiser]

Lou, as I understand the reason it is because you are very likely to split the very thin top edge of the plank below if you nail into it.

[billframer]

i would tend to agree with chuck in the fact that if you place your nailing close to the lip it would possibly blow out. i personally hold mine up a bit on purpose for that exact reason. personal preference i suppose. but you are only talking the thickness of the lip maybe 1/4''?
i'm assuming this is 1x material you are talking about...
bill

[davenorthup]

I've nailed up plenty of 6" reveal this way. You are not 'pinning' the boards together as well...

We have hand nailed all of our cedar and I do not recall splitting more than a handful of boards; if that.

[Alaskan Son]

We hand nail ours as well (with stainless steel ring shanks) and I don't actually recall having ever split any of it.

With the expansion and contraction, you're almost certainly going to split the top of the lower piece if you put a nail through both of them, and if and when it splits, that split may even make its way to an exposed part of the board (depending on the grain).

The idea with lap siding of any kind is to keep the pieces separated to allow for movement, expansion, and contraction. There's really no benefit to nailing the 2 pieces together even if the lower piece was a full 3/4" thick.

Your statement about the nail being way up in the middle of the board makes me wonder if you're trying to use a material meant for a larger lap. The nail shouldn't have to be that far up. With most siding I've used it seems its usually only about 2".


Edit: Actually just checked siding specs and the nail really doesn't even have to be 2" up. It may be as little as 1-1/4" in normal applications.

[Lavrans]

The reason is mostly to keep from nailing both the top and the bottom of the siding. This reduces the chance that seasonal movement will cause that piece to crack in the middle of the board. When the top is pinned by both a nail and the pressure of the board above it, the most likely place the siding will crack in the future is in the middle, where it is visible and allows more water penetration, and the water will help continue the damage.

This isn't just a detail of that particular brand of siding- I haven't seen any wood lap siding that doesn't have that nailing detail (if they offer a detail at all). You can also find it in architectural standards books and carpentry books dating back at least 100 years.

The nail is just supposed to miss the top of the piece below. It can be by 1/10,000 if you're accurate enough. Really, even tacking into the top 1/8" or so won't hurt that much, but it also makes it very difficult to replace a single piece of siding later on if the top of every piece is nailed in...

[tjbnwi]

I agree with everyone else about the install.

I suggest using the Maze StormGaurd cedar siding nails. They are very thin, drive easily.

http://www.mazenails.com/whymaze.php

I believe Bostich has a cedar siding gun, if you don't want to hand nail. Maze may have nails for it.

Tom

[ThingOfBeauty]

This is a funny one.
It's correct that the books & instructions say to nail above the top of the piece below, and it makes sense because it allows the pieces to expand and contract, without splitting from being pinned in two places.
However it is a bit of a challenge to hand nail the thinner and thinner pieces we get without splitting them at the nail line.

Predrilling the end nails does eliminate the most troublesome spot, also nailing kind of right at the edge helps. Old tricks like dulling the nail point, so it smashes the fibers rather than wedging them, are also useful.

I personally have removed a bunch of 10" WRC siding that we nailed "incorrectly" (through both pieces, rather than just above the lap); many of the pieces split and we ended up replacing almost all of it. So, this phenomenon is real.

Having said all that, the vast majority of wood siding is nailed right through both pieces, and the vast majority of carpenters I have worked with have never done it 'by the book' (and think you're a giant idiot if you try to tell them that's how it's supposed to go!).
There are some failures (as mentioned above I've seen it myself) but not that many; and in my experience, I'm more likely to have a problem from splitting while nailing than from splitting later.

My personal, unofficial rule of thumb is 6" lap and smaller, nail how you like; 8" lap and bigger, nail above the piece below.

Here's "the book": http://www.wrcla.org/cedarspecs/ceda...g/overview.asp
click on the installation pdf on the right side:
http://www.wrcla.org/pdf/WRCLA_Installing_Siding.pdf

[BigLou80]

Thanks for the info guys. I guess I have just never seen a failure resulting from the nails going through both pieces and I have worked on lap siding(none of it larger then 6") dating back close to 300 years that has all been nailed through both pieces including our projects original 1840's siding.
What I have noticed is that with this super thin siding the nail has a tendency to bow the siding in because it's not supported by the piece below and even a slight overdrive will cause the siding to split

I guess it's time to change all my future bids to allow for hand nailing

[jimAKAblue]

Thanks for the info guys. I guess I have just never seen a failure resulting from the nails going through both pieces and I have worked on lap siding(none of it larger then 6") dating back close to 300 years that has all been nailed through both pieces including our projects original 1840's siding.
What I have noticed is that with this super thin siding the nail has a tendency to bow the siding in because it's not supported by the piece below and even a slight overdrive will cause the siding to split

I guess it's time to change all my future bids to allow for hand nailing

I think, if you measure the materials that were used back in the 1840's, the thin part of the piece will be thicker than the thick part of the materials of today.

I've never understood, or agreed with the expansion and contraction theory for lap siding. If the material is going to expand and contract that much, wouldn't the split occur under the lapped piece anyways? Does it really matter if the top 1/4" or 1/2" get split off under the lap?

I really never did much lapped cedar siding, so I'm no expert. I did install it on the first structure I built on my own: a garage for ma and dad. I doubt that I was very particular about where I nailed it. It's still standing.

(I might have looked funny with my carpenter book out there on the sawhorses, cutting the rafters.)

[Kent Brobeck]

I guess it's time to change all my future bids to allow for hand nailing

Why couldn't you set your siding gun to leave the nails just proud and finish with a hammer? Plus I'd use stainless siding nails.