OT nails vs screws

Good evening everyone, Just out of curiosity, we don't build (much) with frames around here: Why is building frames with screws prohibited ? (in most cases) http://www.johnlsayers.com/phpBB2/viewtopic.php?t=7380&highlight=nails Thank you in advance, Best regards, Phybeau

This thread, by Rod Gervais, is linked from the Reference Area announcement... Framing - Nails vs. Screws --Keith :mrgreen:

Phybeau, That is code for US, not the Netherlands. Tho I haven't really checked what's best practice/code here in the lowlands. I've seen many frames, many screw AND nails. With metal studs it's either screws or pressed together with special pliers.

Aloha, I had asked a similar question of the contractor helping us repair the recent earthquake damage, and he told me that screws do not have the same "shear strength" as do nails.

Shear strength in mechanical engineering and structural engineering is a term used to describe the strength against the type of structural failure where a component fails by shearing when it splits into two parts that slide past each other.

I don't know if this applies in your area, but it was the info I was given. Perhap Steve or Rod might have a better explanation. :wink: Aloha 8)

I had the opportunity to repair a few structures after the Loma Prieta earthquake here in SF in 89'. THese were built with screw fabrication. THese structures failed miserably because of the poor sheer strength as mentioned. Its just amazing how much side to side force a building must deal with when even moderate earthquakes strike. I would personally never build any home or studio using screws. Use the strongest and deepest nail code demands, and if you can use construction adhesive and Simpson ties additionally. Nothing will fully guarantee non-failure, but these are your best tools.

Thank you! Keith, Rod's post was the reason I asked, as you can see in my initial question :wink: Ro, I'm aware of that, it's just I'm one of those people that always needs to know 'the why' of certain things, in particular legislation. Maybe as a fellow Dutchman you can appreciate that :twisted: Kendale, that was sort of what I thought too. Nails are probably thicker, and thus, have (probably) more sheer strenght. Although, I think, it would certainly depend on the alloy (I'm not sure if that's the right word) of the used materials in nails/screws. n8nod9it, thanks, it's all becoming more and more clear to me now. Best regards, Phybeau

Phybeau wrote:

Ro, I'm aware of that, it's just I'm one of those people that always needs to know 'the why' of certain things, in particular legislation. Maybe as a fellow Dutchman you can appreciate that :twisted:

Same here! We're you stationed? (Leeuwarden myself)

In the beautiful country side around Groningen Ro. So, up north also. **er gaat niets boven Groningen** :wink:

Phybeau, your assumptions as to the reasons for nails instead of screws are correct, as far as they go; also, it's easier to build a smooth fastener with no stress cracks or other flaws than it is to build a THREADED fastener that way - any grooves, etc, are going to be more succeptible to cracking than a smooth nail, even WITHOUT the fact that the nail has roughly twice the diameter at its thinnest cross-section - this translates to 4 times the cross-sectional area, so it's a HUGE difference in shear strength... Steve

Thank you Knightfly! That's a huge difference in sheer strenght indeed. I wonder though, how this translates to the strenght of the construction: with nails you're kind of splitting the wood, and with screws, especially pre-drilled, you leave the structure of the wood more or less intact. For example: If you try to rip apart two pieces of wood that are screwed together, you're probably are going to break the wood. And two pieces, nailed together, can be fairly easily separated. So with screws, the strenght of the construction is going to be determined by the strenght of the wood rather than the object keeping it together. This is just me brainstorming though, nothing scientific :? As said earlier, we don't build much that way around here, and in my case I probably won't either. It's just I like to think about these 'tiny' details sometimes. :wink: regards, Phybeau

Screws generally have better pull-out resistance than nails, but figure that in most framing applications, there's not much need for pull-out resistance. The opposite is true for, say, mounting cabinets on walls. That's why screws are used for that. --Keith :mrgreen:

Luckily we don't experience much earthquakes etc here in the Netherlands. (well, unless there's gas in the ground of Groningen. . . like 2 years ago there was a minor shake due gas IIRC. gheh) I'd ask you local contractor for codes in Holland. Dunno myself, haven't really checked yet since I'm using metal stud for framing :)