screw size to use for framing

Hi
I'm beginning a tiny trailer house ( cabin) and am trying to decide which size screws to use for its framing. I ruled out nails a while ago.
I'm figuring #8 3inch zinc deck screws but....
And,also which size/kind would I use to attach the metal Simpson fasteners that I'll be using?
All suggestions would be helpful.
Thanks
Kate

Katee wrote:
Hi
I'm beginning a tiny trailer house ( cabin) and am trying to decide which size screws to use for its framing. I ruled out nails a while ago.
I'm figuring #8 3inch zinc deck screws but....
And,also which size/kind would I use to attach the metal Simpson fasteners that I'll be using?
All suggestions would be helpful.
Thanks
Kate

For permanently screwing wood together these are the best I have ever used.
Ooooops  I put the wrong link.  sorry.

Katee wrote:
Hi
I'm beginning a tiny trailer house ( cabin) and am trying to decide which size screws to use for its framing. I ruled out nails a while ago.
I'm figuring #8 3inch zinc deck screws but....
And,also which size/kind would I use to attach the metal Simpson fasteners that I'll be using?
All suggestions would be helpful.
Thanks
Kate

Sorry about screwing up the link......Here it is:
http://www.mcfeelys.com/spax-screws/3

Hi Dave
Thanks for the info/link.
I haven't figured out yet which screws have better holding power...#8 or #10's
And am unsure which screws (or should it be nails) to use with Simpson fasteners.
Any suggestions?
Thanks

Do you mean Simpson joist hangers and cross ties etc?  I would use Spax screws with those plates too.  Spax wood screws have oversize threads and really grab the wood and I have yet to have any back out even on the step of my back porch which is heavily used.  They also have exceptional shear strength.  That is my experienced opinion.  The following is from Mcfeely's site.  I am using it because I have done a lot of business with them.

It takes a special screw to make us sit up and take notice. After all, McFeely’s has been in this business for more than 30 years. However, it’s hard to ignore a screw that makes use of unique and patented technology, is made in Germany or the USA (with all that implies about precision engineering) and claims to be useful in materials as diverse as soft wood to plastics to thin sheet metal.



"But the SPAX® fits all those descriptions. At McFeely’s, we like to call it the ‘fastener from the future’. What makes the screw so innovative is its combination of a fully-threaded shank (for most versions) with a patented serration pattern, a patented head style called the MULTIhead, which countersinks the head flush with most materials, and a patented point called the 4CUT ™ which eliminates pre-drilling and splitting because of its square end which divides wood fibers.

That combination of the 4CUT ™ point and serrated thread is effective enough to eliminate pre-drilling unless you’re driving into either masonry or sheet metal better than 24 gauge. A special word of caution applies here, however. The fully-threaded versions of the SPAX® screw doesn’t allow for as much adjustment, once driven, as you may be accustomed to having. That’s because the thread forms a mechanical attachment in both the horizontal and vertical planes. That’s great for fastening items overhead but you may want to measure twice before using these screws. In that sense, they’re advanced fasteners for advanced woodworkers. There are few screws, if any, that will provide for as sound a joint as these. Accordingly, the SPAX ® screws have the German building code approval."

Hi Dave
Thanks for the info.
I live in Canada and have not found Spax screws. Ordering from the US with shipping costs for such an item doesn't fit for my budget ( time or $)
I am trying to understand what the diference in holding power and I guess breaking/snapping weakness is between the sizes of screws. I have access to #8 and #10. Which holds better and is less apt to snap with prolonged jiggling movement?
Yes, I was referring to Simpson joist hangers, hurricane straps and A angles. Is it better to attach those with nails or screws?
Thanks very much for your input.

Generally shear strength is increased with thickness.  I recommended Spax screws because for lumber they seem to hold as well as any other screw I have used and better than lots of brands plus because they start with a serrated point they cut their way in causing less wood splitting. 

I emailed SPAX to find a company in Canada where you can buy them.  I will let you know what I find out.

Dave
Thanks for all your thoughts and for checking with Spax screws for a Canadian distributor.
I think I'm understanding now about screws.
A friend ( two provinces away) suggested to me over the phone last evening to use a screw and a nail on the studs. I smiled as it started making sense. The screw will not pull out but may snap and the nail will not snap but may pull out. Those along with Simpson fasteners will definitely keep the wee house from coming apart while being towed down the highway.
Now I'm researching lag screws....

Zinc deck screws have a strong tendency to tear off the heads when driven in with more than 16 pounds of torque on an electric drill, and it often takes 22 pounds to drive the thing in. 

There is an exterior screw on the market produced by Grip Rite.  Look for Primeguard 10.  They are grey.  There is a coated decking screw designed for pressure treated lumber, tan in color.  I swear by them instead of at them.

If you have a moist piece of wood with metal stuck into it connected to the ground, you essentially have a battery on your hands.  While the reaction is slow and the voltage is negligible, the effect on the hardware is corrosion.  Have you ever pulled apart an old shed to find rusty nails?  The coating on these screws reduces the cathode effect, making the hardware last considerably longer.  The screws also drive in easier. 

The head on these screws is bugle shaped, as with drywall screws.  The bugle shape is used to make it easier for the head to penetrate the wood.  Standard wood screws have a cone head which is more prone to breaking the wood around the head.  The bugle shape compresses the wood.  You'll be able to see this best in pressure treated limber.  Juice will ooze out when bugle shaped heads are used.  the zinc screws you mention have a bugle head, but the metal is not strong which causes the failure.

I lack the coordination needed for successful hammer and nail use.  The only thing I hit with a hammer is the hand holding the nail.  Its ugly I tell you.  It is so bad I've had to look into screws and do some homework.

If you have your heart set on using zinc, I suggest you pick up a small box of the primeguard screws, do a side by side comparison, and be sure to save the receipt on those zinc screws so you can take them back.

She is building a tiny home on a trailer not the earth.  No electrolysis problems.

I like to tack with a framing nailer and then come back with the screws. I like the fact that I can "nudge" with a hammer after I have tacked (if something is slightly off). If you use screws first, you better back them out if you need to adjust something.

If you're looking for added holding strength, shoot the screws in at opposing angles.

Katee wrote:
Dave
Thanks for all your thoughts and for checking with Spax screws for a Canadian distributor.
I think I'm understanding now about screws.
A friend ( two provinces away) suggested to me over the phone last evening to use a screw and a nail on the studs. I smiled as it started making sense. The screw will not pull out but may snap and the nail will not snap but may pull out. Those along with Simpson fasteners will definitely keep the wee house from coming apart while being towed down the highway.
Now I'm researching lag screws....

Canadian Company for SPAX screws:

http://www.leevalley.com/en/hardware/page.aspx?p=40555&cat=3,41306,41315&ap=1