Screws instead of Nails in Framing - ok?

Posted: Sun Sep 10, 2006 10:56 am

Guys were chatting about how to frame walls in a basement, and someone wrote

Quote:

Originally Posted by rlindo "Oh and make sure to use screws for your framing. Nails are silly."

Nevermind the fact that this is against code. Screws do not have the shear strength of nails. Nails will bend but continue to hold, screws will snap.

from: http://www.avsforum.com/avs-vb/showthread.php?p=8355195&&#post8355195

Are screws against building code for framing?

Posted: Sun Sep 10, 2006 1:16 pm

Yes they are; nowhere near the sheer strength, due to the thinness caused by threads. Also, if screws were legal some bozo would use brass ones, weakening sheer strength even further... Steve

Posted: Sun Sep 10, 2006 3:01 pm

Thank's Knightfly. That's unexpected.

Nifty.

Perhaps I'm defining framing incompletely. When framing a house there's lots of things (roofs, floors, walls, decks, wood/concrete), and I've seen all kinds of things used to connect them all.

In this case I'm thinking of 'framing' being just stud walls in a basement.

There's a TV show called "Holmes on Homes" Burlington Ontario Canada, and he uses screws for all his basement stud walls. i.e. he puts in a bottom plate (tapcon to the floor) and a top plate pair (screwed to joists), and then cuts each 2x4 stud and screws them to the top and bottom plate. He does this all the time. And he's constantly going on about how "other contractors build to minimum building code, and he goes better". I wouldn't have thought that sheer strength would be all that important in a wall. But, on the other hand, Holmes On Homes uses screws in his joist hangers too, and there's certainly sheer going on there.

I have a copy of Ontario Building Code, so I could look up what the rules are here. But mostly I was curious about American Building Code which I don't have.

A screw with the middle (not including the threads) that was as thick as a 4" spiral nail would be a fairly thick screw.

Posted: Sun Sep 10, 2006 8:23 pm

z60611 wrote:

Thank's Knightfly. That's unexpected.

Nifty.

Perhaps I'm defining framing incompletely. When framing a house there's lots of things (roofs, floors, walls, decks, wood/concrete), and I've seen all kinds of things used to connect them all.

Framing (by definition) is the structure of a building to which finish materials are attached to .

It makes no difference whether it's bearing or non-bearing in the States - if it's framing - it's framing.

Quote:

A screw with the middle (not including the threads) that was as thick as a 4" spiral nail would be a fairly thick screw.

Sure would - BUT - it still would not have the shear value of that same nail.

In order for framing screws to work (picture decking screws and the like) they have to be case hardened....... and it is that which makes them brittle.

In the States - all wood framing is to be nailed unless an engineer can prove (through the use of calculations in accordance with the design requirements of the code) that screws will be an equvilent method of attachment.

And, seeing as that would have to be done on each project - (this because each project has different things driving the design) it really wouldn't be cost effective to even bother.

Heck, The code even proscribes the minimum amount of nails (and sizes) for each condition.

Sincerely,

Rod

Posted: Sun Sep 10, 2006 9:31 pm

What about commercial steel framing?
I may be wrong but I think all public buildings must use steel framing now for fire code.
It's all assembled with screws.
Larry

Posted: Sun Sep 10, 2006 10:50 pm

Quote:

In the States - all wood framing is to be nailed

Then I'm screwed—if I only used non-nail fasteners to hold framing together?

But wait—if you're just building non-supporting partition walls that will only hold up gypsum wallboard, do any shear forces to speak of really come into play? I can imagine top plates and bottom plates held to studs purely with vertical screws; and if you screw wall corner studs together, with both frames' sole plates resting on the same floor, then there are no shear forces involved there either, right? Or doesn't national US code care?

Does this mean—purely hypothetically of course—that if all my basement framing were currently held together only with screws, then to conform to national building code I would have to toe-nail actual nails into all my existing exposed framing where they meet other framing members (top plate, sole plate, corners, double-studs around doorways and windows)?

Would Simpson ties (metal angle brackets with pre-drilled holes) using multiple screws at each juncture be an acceptable means of holding simple basement framing together?

Lee

Edit:

Quote:

Heck, The code even proscribes the minimum amount of nails (and sizes) for each condition.

OK, sorry I missed this in my haste. Can someone quote a chapter and verse on this that I could look up online? I'm mostly interested in toe-nailing studs into top plates and sole plates.

Posted: Sun Sep 10, 2006 11:22 pm

In Ontario (canada) Building Code section 9.23.3 gives lots of examples/tables of using nails for connecting various types of framing.
The only examples/tables for screws that I see are for gypsum, sheething and subflooring, and steel.

I didn't see anything that excludes screws. But I didn't see anything that excludes the use of chewing gum as a fastener either. I did see they keep saying 'so many nails of such and such a type and such and such a size at such and such a place and such and such a separation'

Posted: Sun Sep 10, 2006 11:40 pm

Hmmm....

Posted: Mon Sep 11, 2006 9:13 am

jazzman_in_pa wrote:

But wait—if you're just building non-supporting partition walls that will only hold up gypsum wallboard, do any shear forces to speak of really come into play? I can imagine top plates and bottom plates held to studs purely with vertical screws; and if you screw wall corner studs together, with both frames' sole plates resting on the same floor, then there are no shear forces involved there either, right? Or doesn't national US code care?

Lee,

what about seismic forces?

Quote:

Does this mean—purely hypothetically of course—that if all my basement framing were currently held together only with screws, then to conform to national building code I would have to toe-nail actual nails into all my existing exposed framing where they meet other framing members (top plate, sole plate, corners, double-studs around doorways and windows)?

OK - first off - there is no "National Building Code" - each state has their own code that they enforce.

Next - it does mean that - yes you would be required to fasten according to the fastening schedule as a minimum - although you are always aloowed to use larger fasteners (remember the code is a minimum standard).

You could also have an engineer provide calculations of what you have - and if the numbers work, then he could certify it as an equivilent method.

Quote:

Would Simpson ties (metal angle brackets with pre-drilled holes) using multiple screws at each juncture be an acceptable means of holding simple basement framing together?

Nope - when you install an engineered member for fastening purposes - it is tested and approved in accordance with the manufacturer's design - and I have never seen anything from Simpson that allowed the use of screws for that purpose. They always specify nail fasteners.

Quote:

Can someone quote a chapter and verse on this that I could look up online? I'm mostly interested in toe-nailing studs into top plates and sole plates.

I try to get athe info on the fastening schedule in the IBC for you.

Sincerely,

Rod

Posted: Mon Sep 11, 2006 9:17 am

omegaarts wrote:

What about commercial steel framing?
I may be wrong but I think all public buildings must use steel framing now for fire code.
It's all assembled with screws.

Larry,

1st - you are mistaken - any public building up to 3 stories in height can be wood framed.

Next - note that all of my references were specifically related to wood framing.

Obviously steel frame cannot be nailed - and in that case - it is required to fasten in accordance with the Manufacturer's (or Engineer's) fastening schedule.

Sincerely,

Rod

Posted: Mon Sep 11, 2006 9:20 am

z60611 wrote:

In Ontario (canada) Building Code section 9.23.3 gives lots of examples/tables of using nails for connecting various types of framing.
The only examples/tables for screws that I see are for gypsum, sheething and subflooring, and steel.

I didn't see anything that excludes screws. But I didn't see anything that excludes the use of chewing gum as a fastener either. I did see they keep saying 'so many nails of such and such a type and such and such a size at such and such a place and such and such a separation'

The fact that you see screws allowed for specific items - and not for other specific items - is the defining requirement.

Yes you can screw or nail drywall - decks and sheathing - and because both are allowed - they have fastening schedules for both methods - but not for framing.

Therfore only nails are acceptable.

Sincerely,

Rod

Posted: Mon Sep 11, 2006 9:22 am

Folks,

don't get me wrong here - I am not suggesting that your rooms are going to fall down if they were screwed instead of nailed.

Rather - I am just speaking to what is (or is not) allowed by code.

Sincerely,

Rod

Posted: Mon Sep 11, 2006 11:15 am

Thank's Rod.

I note that the Holmes On Homes guy (who screws basement studs)
a) passes building inspections - so the building inspectors think whatever he's doing is fine. Given your comment above about engineer approval, perhaps two screws of some size is equivilent to one nail in the case of non-load bearing basement stud framing. I don't know. Nails for me, perhaps with an extra screw.
b) the show always starts with something like "This show should not be taken as a diffinitive text on building practices."
c) when googled, there's a couple of contractors who: "I'm watching an episode right now and it's tough to keep from yelling at the TV. Holmes is a boob. He was hired to be a host and he has about as much construction smarts as your average TV host." Personally I thought that wording was a bit strong -- Holmes does some good stuff too, but even I've spotted a mistake or two. Obviously I missed this nailing bit. Smile

Posted: Mon Sep 11, 2006 1:32 pm

Rod, and Z,

Thanks for the eye-openers, regarding nails versus screws. Never thought of seismic forces here in this neck of the woods, but if the earth moves, I sure wouldn't want my triple-layer walls come crashing down on any of my loved ones.

And Rod, I'm really thrilled you're back to form so soon after your operation. You're acting like you're up to full speed. I hope you're feeling as good.

Lee

Posted: Mon Sep 11, 2006 1:33 pm

z60611 wrote:

a) passes building inspections - so the building inspectors think whatever he's doing is fine.

Z,

Understand something - in all of my career I have met perhaps a handfull of building officials who actually know what they're doing and understand the code - the rest of them (i.e.: the vast majority) do not have a clue.

So, the fact that someone does something that's a code violation - yet it passes inspection - is no big surprise to me.

BTW - one of the services I perform is Code Review - so I do have a pretty good sense of what the codes are all about.

Sincerely,

Rod

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