Threaded Fasteners for Outdoor Projects

Choosing the right fastener for your outdoor project can mean the difference between an attractive looking enhancement to your property and a rickety, rusty eyesore….or worse , a dangerous liability. While hand driven nails once reigned as the fastener of choice for outdoor structure, and the unmistakable pop of the pneumatic nail gun can still be heard on construction sites everywhere, the selection of premium quality threaded exterior bolts and screws available to the outdoor builder make it possible to not only build much stronger, but also more attractive structures.

While nails are fine for securing smaller pieces of wood to a structure, threaded fasteners offer much greater strength, are easy to install without damaging the wood surface and remove or adjust if needed.  Galvanized fasteners, which have been hot dipped in molten zinc, and stainless steel fasteners offer the most corrosion resistance from weather and the naturally alkaline chemicals present in rot resistant wood species like red cedar. While all metal exposed to the elements will eventually rust or corrode, investing in these premium grade fasteners will reduce the amount of streaking and staining of the wood over time. 

Lag Screws

These threaded fasteners are used along with a washer to join large structural pieces of lumber like a post to beam on a pergola, for example. Common sizes for outdoor projects are 5/16”, 3/8” and ½”, which represents the thickness of the shank, not the head. Pre-drill the hole with a bit one size smaller than the shank, and drive it in with a socket wrench.

Carriage  Bolt  

Like lag screws, carriage bolts are also used to create a strong face to face joint between structural lumber, like posts and rails on a fence. The design features a plain oval head that doesn’t require the use of a washer between the bolt's head and the wood. Carriage bolts have a square shoulder that digs into the wood when tightening, preventing slippage, and are fastened by a washer and nut secured to the threaded end that typically protrudes about an inch on the opposite side of the second structural piece.

Common shank sizes are 5/16”, 3’8”, and ½”, and a hole matching the size of the shank must first be drilled completely through the two pieces of lumber. Use a hammer to drive the bolt completely through both pieces of wood, sinking the square shoulder so that the oval head sits flush with the outer piece of wood. Place the washer and nut over the protruding portion of the bolt on the opposite side, then tighten the nut with a ratchet.

Timber Lok

These high strength steel fasteners claim to be stronger than a 3/8” lag screw, and while that's up up for debate, there’s no question that Timber Lok fasteners are really strong and easy to work with. While they’re designed to drive right into pressure treated landscape timbers, we’ve found that when working with red cedar, a pilot hole must first be drilled. The built in washer helps the screw create a very solid joint, and this is our go to fastener for making the 4x4 Cedar Timbers raised bed design, or in structural applications like securing a greenhouse wall to a timber base, for example.

Deck Screws

While they take a little longer to install than using a nail gun, exterior screws create a much stronger connection, and are easy to remove if a structure ever needs to be taken apart and moved, repaired, etc. 

Using exterior screws instead of nails to fasten boards to a structure also means there won’t be any marks left on the project by hammer blows, and the lightweight, battery powered drill & driver sets on the market make installation almost as fast as a hammer and nails. Polymer coated designs are made to drive in easy and resist corrosion even in cedar and redwood, while stainless steel is the pinnacle of rust resistant outdoor durability. 

Roofing Screws

Whether securing metal roof panels to a chicken coop, or polycarbonate glazing to a greenhouse, special wood screws that include a rubber washer are needed to create a watertight seal and prevent leaks. Typically the roofing or siding manufacturer will offer screws designed to be used along with their roofing and siding products.

Poultry Net Staples

Nothing like what’s in the stapler on your desk, these ¾” hot dip galvanized fasteners are ideal for securely fastening hardware cloth to chicken coops or wildlife barrier fencing. For most projects, space poultry net staples about 6-8” apart, and a simple 16oz hammer will do the job. Always remember to wear safety glasses when hammering poultry net staples, or hammering anything for that matter.