Decks, Patios, Porches and Docks - SDS Screw

I read somewhere about an SDS screw. These apparently are used for attaching ledger boards for decks insstead of lags.

What exactly are they?
What does SDS stand for?
Where can I get them?

Thanks.

rdhamm,

All answers here,

http://www.strongtie.com/products/connectors/screws.html

Any major lumber yard, possibly a bix store.

Hope this helps!

I'm a bit confused. It seems that SDS is a trade name by Simpson.

I'm not sure, but do codes often refer to manufacturer specific items? That seems odd to me.

Perhaps I am wrong and SDS is a generic name, like 'lag'.

rdhamm,

It is a Simpson Screw - Strong Driver - That is what they use for their abbreviations on products.

It looks like a lag and performs like a lag screw. No difference.

Hope this helps!

Hope it's OK to add one more thought here. The main difference in SDS screws and lags is that the SDS don't need to be pre-drilled. Apparently, this is why some counties are requiring them now and not accepting lags....guess too many lags were being improperly pre-drilled, or not drilled at all.

The shear strength of an SDS is about double that of a common lag bolt. That, and improper predrilling is why many counties are not allowing lag bolts to attach a ledger board. I happen to be in one of the first counties that refused to recognize lag bolts. If I attach a deck via a ledger board, I almost alway have to thru-bolt it. Therefore, I do mostly free-standing decks. And a free-standing deck will NEVER result in a hole in the siding that water or moisture can enter into and rot the framing of the house.