Hi,
Are nails better against lateral forces than screws? I often read contradictory statements about screws and nails. Screws are supposed to hold things together better than nails due to the expanding/contracting nature of wood in different temperatures and moisture conditions but I’ve often read that you should not use screws in joist hangers and other connectors.
Someone said it is because screws can break easier under lateral forces – I have broken screws while putting them into mdf but I have never broken a nail but that is likely bc I have never put a nail under torque – is that true?
Air driven fasteners vs normal fasteners. Simpson strong tie joist hangers typically specify the size of the fasteners that are required to fill the holes in their hardware. The stick nailer that I have will do .113 to .131 @ 2″ – 3+1/2″ length. Most of the connectors say to use 16D which is .162 in common. Is the common practice to hand nail connectors and air nail general framing? I have seen ads for a connector nail gun which keeps the nail point outside of the barrel for accurate aiming – I take it this nail gun would take nails of the proper diameter?
Mending plates, nailing plates. What are these good for? If I have a 4×4 post that I undermine and want to extend it could I put another piece of a 4×4 post under it attach a mending plate to the sides and consider it good as a full length one? I see in framing the cheaper studs are dovetailed – not sure if that is the correct term – together in multiple areas – apparently so the wood is straighter, less susceptible to warping and I guess cheaper. Some literature says that those bonded areas and the glue used is in fact stronger than the wood fiber bonds in normal studs – is that true?
Thank you for any advice.
learner
Replies
Nails vs. screws really depends on your application. If you're using a listed metal connector--a product from simpson for instance--then the manuf. will specify the # and type of nails to be used, and there are screws that may be specified also, but as a rule one is not better than another. Follow the connector manuf's specification to the letter to avoid any issues.
And, with PT material you must use a stainless or hot-dipped galv. fastener and/or connector.
As far as scabbing a post bottom--this will depend on what that post is holding up. You may be able to do what you propose, but if you're concerned you should consult a structural engineer.
Yes a glue joint can be stronger than the wood around it, but again how the material is joined and used will change it's potential.
"Research is what I'm doing when I don't know what I'm doing..."
Drywall type or general purpose construction screws are typically made from a harder - and more brittle - steel than nails. So they can be problematic under shear loads, though stronger in withdrawal.
Lateral loading is different from shear loading, however. Shear is a force applied perpendicular to and directly on the fastener (such as a joist hanger). Lateral loading is a perpendicular force applied to two or more fastened wood members (such as with a built-up beam). The resistance to lateral loading depends on the compressive strength of the wood, the diameter of fasteners, and the friction between wood members. Resistance to shear is determined only by the size and material of the fastener.
A screw can "pop" as easily as a nail (for instance, drywall into studs), because the wood will shrink from the outside inward, leaving the fastener extended.
But there are screws designed for construction, such as TimberLoks, LedgerLoks, TrussLoks and HeadLoks which are shear rated and engineered for specific structural applications.
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Like they all said above, and if you use the search function and have the patience of Job you can follow the past acrimonious debate about this subject.
The wood stud product you are referring to is "finger jointed"
And a little more detail on Joist hangers.
Yes, the thicker nails for joist hangers, plates, etc are typically sold in boxes adjacent to joist hangers in the big box stores and suppliers will have them as well.
Commonly referred to as joist hanger nails or hanger nails, they are what is specified to be used with joist hangers, truss hangers, etc.
Some plates and hangers permit the use of 16 D nails in lieu of hanger nails but you must be certain you are using the right product for your application.
Regarding the direct nailers, yes, they shoot the correct nail for the joist hangers.
I have used them now and again but dont do enough framing to justify owning one.
I hand nail all my joist hangers. With exterior decks, I typically install the hangers on the ledger while the ledger is laying flat on saw horses prior to installing it on the house band so it is easier to nail.
learner
This has been so completely discussed over the past that I feel wrong to respond further..
Ah well Piffin and I can rehash old debates once again <grin>
Yes some nails have greater resistance to shear loads for a given size however screws have greater resistance to extraction.
Not all screws however fail in the shear tests..
The fact however is that the time required to properly install screws is massive compared to the time required to pull a nail gun trigger.
To properly install a screw there needs to be a pilot hole drilled first, a hole equal in size to the shank, and one for whatever counterbore to properly recess the head..
While it is possible to buy a bit which will do all three steps at once they are not cheap nor are they particularly durable..
ON the other hand extraction of a screw requires wood to yield to failure while pulling a nail is a relativelu simple procedure..
Take a claw hammer and you will easily be able to pull a large nail while a similar sized properly installed screw will unlikely yield even to the force of a large crow bar..
Alright thanks everyone for rehashing the topic for me. I'll do some searching for the original fastener topics to gain insight. I think I'll take the general approach of stick nailing normal framing with the jlc field guide air nailing replacement schedule and using the fastener recommendations for the connectors from the manufacturer with hand fastening.What manufacturers do people source their connectors from? I've used Simpons Strong Tie, Stanley and HillmanGroup. I am sure there are others that I should look at as well.Thanks,learner
Exactly what is the project that you are doing?
What's your expertise with tools so far?Rebuilding my home in Cypress, CA
Also a CRX fanatic!
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