Deck Screws Vs Joist Nails

neolitic

I think it is just an awkward way to
say that they are the same head
and gauge as a 10d nail.
It is more recognizable than 9ga.
9ga doesn't put a picture in my
head the way 10d does.

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BuiltByMAC

Not sure why you're looking for additional proof - all the responses here are from guys who build w/ both nails and screws and know that screws are more brittle than nails. Period. Sounds like you're working on a thesis project for a Comm. Col. Construction class...

Nail a brand new 10dx3" nail halfway into a board -
Screw a brand new #10x3"deck screw halfway into a board -

hit them from the side w/ a hammer
hit them on the other side w/ a hammer
at this point, if the screw hasn't already broken off, twist it w/ your fingers. It will probably fall off in your hands. The nail will withstand multiple hits because it is better able to withstand shear forces.

On a deck, joist hangers are placed at a point that will receive shear forces (due to nature or too many people on the deck). It only makes sense to use fasteners that are designed to withstand shear forces for your joist hangers.

You ask "how can we help your inspectors know the difference?" Have the documentation printed out and available for them when they come to your jobsite OR go to the planning and dev. dept, show them the documentation (from Simpson) and have them sign off on the jobsite copy of the plans.

If they are worried about nail withdrawl and nix using hangers w/ nails because of that fact (like my city), here is the workaround:
wrap 24" Simpson straps (MSTA24) around the back of your ledger board before you install the ledger. Position the straps every 4' so they fall on a joist. Once you install the joists and LUS hangers, nail the straps (w/ 10d x 1 1/2" HDG nails) to the top and bottom of the joist. That detail will satisfy the city's concern over nail withdrawl on joist hangers.

Mac

jeffaah

Now I have a question

I pretty much use 3" HDG commons on all my hangers. Since the ledger has the house behind it and the rims are all doubled, no nails will poke through.

I figure the 3" is always better then 1-1/2" given they are the same diameter.

Am I wrong?

jarhead0531

That is great tip Mac, never heard of that one before. I may incorporate that into my elevated decks from now on. I like the double shear because it makes nailing easer but it seems like the pull out resistance has to be less. Best part is total cost per deck is probably still less than $30 (I have no idea what those costs).

Nothing wrong with what you doing jeffah, I often will tack the hangers in place with 2 10d commons into the ledger, hammer off the shear nailing then come back later with the strapshot to finish off the hangers if I'm working off a ladder. I work alone and working off ladder putting a joist in position and trying to keep from tripping over air hoses is more than I can manage at one time. If I'm at a more resonable height I still tack it in the same but have the starpshot close at hand to finish it off. It is the diameter of the nail that is important in that case, length isn't as critical, but those two long nails do make me feel better for no real reason.

Is it just me or with the shear hangers do you find yourself hand nailing them more than reaching for the palm nailer?

Barry

subybohn

Well, I'm not a builder or a pro -- but I have built over 30 decks....through volunteers.

Because I am not building for money or profit, I like to look at ways to build and products used.

So a thesis is close -- but not for a Community College...

I study manufacture recommendations and compare it to what builders are really doing....and what inspectors over rule.

Engineers say screws -- builders say nails....

I see both aspects.

And yes, if you strike a nail from a side force, the nail "bends" -- this is not shear unless the hammer is sliding on the on the face of the board.

If you do the same to a screw -- you either have to use more force or the screw moves in the wood --

Think about kitchen cabinets -- they "hang" on the wall. Do you install them with nails or screws? Screws.

Friction holds the cabinets to the wall, not the screws. Screws hold the cabinets tight to the wall to create the friction. Nails pull out.

If screws are holding the hanger to the header board, you have friction so unless the hanger is allowed to slide; the screw will not be in shear.

If the hanger will not move because of the friction the screw are maintaining, then the 1-1/2" bearing plate will be the perfect "ledge" for the joist to sit on -- and all the joist plate really needs is a screw to create friction so the joist does not slide out...

So even though I talk nails vs. screws -- it's actually friction -- and which fastener holds the hanger tighter to the wood to create that friction -- nails or screws?

DecksEtc

The next time you have 40-50 people standing on top of your cupboards, let me know how those screws work for you

The bottom line is that the building codes for where I do all my work maintain that all holes in the joist hangers have 10d nails in them - screws won't pass inspection - end of discussion.

subybohn

I have an older Simpson Tie catalog (2003) and it lists the products in price order (last column)

For 2x10 joist:

The LUS28 with 6-10d in the Header and 4-10d in the joist (notice which has more fasteners to show the importance) is listed as the "lowest" cost - 18 gauge but 930 (133) uplift.

Next is the LU28 with 8-10d in the Header and 6-10dx1-1/2 in the joist (notice which has more fasteners to show the importance) is listed as have a +13% cost over the LUS28's - 20 gauge but only 735 (133) uplift.

So using the "1-1/2" Joist Nails" you are using a lesser gauge of hanger, installing more fasteners, and loosing important uplift allowable loads -- and it costs more than their LUS28 -- the Z on the end means Zinc. (LUS28Z)

I quoted the 2003 catalog, because their web-site does not list the "Installed Cost Index (ICI) -- and not sure if their newest catalog still does.

h ttp:/www .simpsonstrongtie.com/products/connectors/LSU-LSSU.asp

subybohn

Cabinets are not made out of 18 gauge or 2x10's -- so the cabinet will break before the cabinet slides off the wall.

Exactly -- screws won't pass inspection...

So is it because Engineers say yes and builders say no -- and inspectors are builders?

Screws take longer to install & cost more then nails -- and builders don't have time and need the profit.

But I also hear of increasing deck failures -- due to their popularity and the number of people trying to cram onto them.

So why are screws NOT being tested as a viable alternative and not as a replacement to nails in deck construction?

subybohn

I too purchased 10d Hot Dipped Galvanized "BOX" nails from Menards -- but box nails do not have the same diameter as "COMMON" nails.

As stated before -- just because they are 10d - they come in different lengths (1-1/2" = 10d Joist Nail) but mostly 3" -- different diameters/gauges (9 gauge = 0.148 which both 10d common and 12d common nails are as well as 16d sinkers) -- and different designs and different heads (Ring shank, common, box, spiral). So 10d really only symbolize the length not the gauge or “double shear factor” needs.

10d spirals are only 0.132 but because of the "spiral design", Simpson's 2003 catalog says they can be substituted for 10d common without any Load adjustment factor for hangers in double shear. (Notice the hanger/joist is in double shear, not the nails – the joist, if given the opportunity, will try to either slide up/down or pull away from the header – the toe-nailing cross application is what is preventing this with the help of the hanger. And in order for the hanger to help, it relies on the friction gained between the hanger and the wood. The strength is in the hanger, not the fastener.)

Where do you think I got the idea to use screws from? -- If a smaller diameter nail with spirals has the same Shear as the 10d common, the necks (area without threads in the shear plane) of the deck screw are larger then the 10d spiral.

However, I think others have also made this connection, for you will NOT see 10d spiral listed on their web-site any more.

Menards does sell a 10d HDG spiral deck nail - 229-3844, 229-3815, 229-3750 (1lb, 5lb, 50lb) - but I have not found them on the shelf, nor do I know the diameter of these but assume they are the design standards of a spiral nail...so are Menards "deck nails" also a viable alternative to Simpson's 10d-5HDG 3" nails.

I'm down loading USP's catalog to see what they say.

BuiltByMAC

If you hit the nail and screw from the side, horizontally, where they connect w/ the wood, that's shear. And no, you don't have to hit the screw harder to make it snap. Have you never tried this IRL? Christ, dude, go do the experiment I described, you'll see for yourself.

Sorry, too early in the morning to try and sort through the technical facts you're proposing...though I am laughing my ass off at DecksEtc response to your cabinet comparison!!

I must correct at least this much: the "Z" in Simpson hardware stands for "ZMAX," a galvanized coating that makes the hardware minimally acceptable for use w/ ACQ treated wood.

Mac

subybohn

Thank you for the correction -- my local lumber yard told me it was for Z=Zinc not ZMAX.

This wasn't the first time I read this test.

Contractor Talk - Professional Construction and Remodeling Form > Trade Talk > Construction

Screws vs. nails (03-11-2005)

Teetorbilt, moderator stated:

"I almost launched into a dissertation, but, in a nutshell, when comparing nails to screws, screws will prevail in every instance."

This was back in 2005 -- but it's now 2008, and where I live, the inspectors are still making us use those 10d-1x1/2" joist nails - because "that's what they were designed for....

I thought there would have been more progress made on this discussion since Deck Screws are now used instead of "drywall" screws or galvanized screws.

We use screws/lags EVERYWHERE in decks except in the hangers... because common nails are not holding in expansive/contractive conditions for nails definatly need their 1-3/4" penetration which is less than a 2x4 thickness to hold tight.

So why are we STILL using them in hangers and why have they not been looked at as a viable alternative to 10d x1-1/2" joist nails -- or one developed especially for exterior decking hanger use?

jarhead0531

You really just aren't listening to anyone. What engineers specified to use screws on the hangers?? Pretty uncommon for an engineer to go against manufacturers recomendations.

To makes things PERFECTLY clear for you though. Screws are SLOWER, WEAKER, AND MORE EXPENSIVE I have never heard of a deck failing when joists are properly attached to correctly secured ledger, so tell us why it is necesary given the forces exerted on joist to use screws.
There is absolutely no benefit, and many downsides.

We use screws in decks where pullout resistance is important, and no place else. I don't use my hammer to drive screws, I don't use my impact driver to drive nails. Right tools for right situation, right fastner for right situation. End of story.

Barry

Dan_Watson

Not even close. When manufacturers, engineers, and builders calculate for fasteners friction is not even computed. It has too many variables. What happens when the wood dries and skrinks? Is the friction less now becuase the boards are further apart? What happens if one side of a board has mold, mildew, or moss on it creating a surface that would have less friction? FRICTION IS NOT WHAT HOLDS **** IN PLACE in the situations you talked about.

Can you show me where engineers are stating screws are stronger and should be used for joist hangers. I am pretty sure the manufacturer states nails, beacuse they have engineers, and lots of testing to prove nails hold better.

BuiltByMAC

You could have figured out the Z thing from Simpson's website, easy.
And while Teetor is a frequent poster here on ct, I don't take his posts as gospel. He knows some things about building but not everything...like most of us.

My on the job experience taught me screws are more brittle than nails - everyone who's bothered responding to this thread has figured out the same thing. No, not all of us put the whole deck together w/ screws. Most of the high-end builders (guys who know their sh:t) use a combination of nails and screws for the structural framing. Screws prevent pullout, nails prevent fastener failure due to shear forces.

I'm not buying the friction argument. Screws are holding up your cabinets. The other reason people don't use nails to install cabinets - they're going on a finished wall. Who wants to chance putting a half-moon in newly painted drywall?

You're tenacious, I'l give you that. However, you're on the wrong path. Good luck w/ your research.

Mac

neolitic

To further muddy the waters,
before the 60's most of the cabinets
I've seen were put up with nails.

How about a little background here?
We've all poured ourselves into this thread,
(which might turn out to be a good resource)
how about you explaining what you are doing,
and where you are coming from?
I'm unclear whether this is practical
or academic.

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PA woodbutcher

Take 2 2x4s and nail then together (using 2 nails) with one hanging 4" over the other and put a jack under it. Try the same thing with screws and see which has the most shear strength. When your done with that go ahead and do what you want, you will anyways. You are obviously way to smart for the rest of us "simple" carpenters.

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RobertCDF

You should write and email to simpson and USP telling them that they are dumb and should use screws. At that point I am sure they can show you $100,000+ worth of R&D as well as testing for use of screws in their hangers. And they will tell you that nails are better all around for hangers.

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Dan_Watson

Who are you talking to?

subybohn

That's exactly what I AM looking for -- PROOF that nails DO hold better than screws in joist hangers.

Where do I find it?

Or have screws not been tested because nails are sufficient.

If the manufactures have done the testing, you would think I could find the results -- but the only thing I get is (from Simpson Ties):

"We can only support the loads with the specified/tested fasteners. We
have specific models that are rated with our SDS screws but we have no
information on using deck screws. The holes on many of the nail-on face
mount hangers are not sized to accommodate screws and we have not tested them with this fastener.

The Designer/Engineer of Record can specify a substitute screw that fits
properly, but he/she would need to recalculate the capacity and would be
taking responsibility for this application."

Repeat "The Designer/Engineer of Record can specify a substitute screw"...

So, has anyone done this?

neolitic

Are you "confused"?

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