Lag Screws

Select diameter based on load and wood type—common diameters range from 1/4" to 1/2" or larger for heavy loads—and choose a length at least 2.5 to 3 times the thickness of the member being fastened into the receiving material to ensure adequate embedment; when joining two pieces, add thickness of the first piece plus required embedment

Use stainless steel or hot-dip galvanized lag screws for exterior or pressure-treated wood to resist corrosion; zinc-plated bolts are suitable for indoor, dry environments but are less corrosion-resistant

Yes—pre-drill pilot holes to prevent splitting and reduce driving torque; use a pilot hole diameter about 60–80% of the lag screw shank for softwoods and close to the screw core/inner thread diameter for hardwoods, and use a larger clearance hole through the first member if necessary

Hex heads are driven with a wrench or socket and offer higher torque for heavy-duty fastening, while hex washer heads or flanged heads spread load; choose drive style (hex, square, or combination) compatible with your available tools and torque requirements

Look for material grade (stainless vs carbon steel), thread type (coarse for softwood, full thread for pull-out resistance), and published shear or withdrawal strengths if available; when not provided, size and material are primary indicators of capacity, and consult engineered tables for critical structural uses

Periodically check for loosening, corrosion, or wood deterioration around the fastener, tighten if necessary without over-torquing, and replace visibly corroded or damaged screws—use compatible corrosion-resistant replacements in exterior or treated-wood locations

Lag screw packs and individual prices vary by size, material, and brand; you can find budget options under $50 for basic carbon-steel packs, while specialty stainless or large-diameter screws cost more; higher-cost items often use more corrosion-resistant materials or larger sizes but always verify material and finish rather than relying on price alone