5/16 x 4" Hex Lag Screw
Available for delivery in 3–14 business days.
Please, contact us to confirm pickup availability.
5/16 x 4" Hex Lag Screw
5/16" x 4" Hex Lag Screw – Heavy-Duty Fastener for Structural Outdoor Applications
The 5/16" x 4" Hex Lag Screw is a strong, reliable fastener ideal for heavy-duty structural connections in decking, fencing, pergolas, and other exterior construction projects. Designed to provide maximum holding power in wood-to-wood applications, this lag screw features a hex head for easy driving with a socket or wrench, ensuring a tight, secure connection that lasts.
Key Features:
✔ Heavy-Duty Performance – Designed for high-strength fastening in wood-to-wood construction, including ledger boards, beams, and posts.
✔ Corrosion-Resistant Finish – Coated or galvanized options available for superior resistance to rust and outdoor exposure (check specific product finish).
✔ Hex Head Drive – Compatible with standard sockets and wrenches for high torque applications and easy installation.
✔ 4" Length for Deep Penetration – Ideal for thicker materials and structural connections requiring extra holding depth.
✔ Versatile Use – Suitable for both residential and commercial outdoor builds.
Technical Specifications:
Diameter: 5/16"
Length: 4"
Head Type: Hex head
Drive Type: Socket or wrench
Thread Type: Coarse, partial thread
Material: Steel (coated, hot-dip galvanized, or stainless steel – varies by model)
Application: Wood-to-wood fastening for structural outdoor or indoor use
Common Applications:
Deck Framing – Secure ledger boards, beams, and joists to structural supports
Pergolas & Pavilions – Fasten posts, headers, and rafters for long-lasting stability
Fencing – Anchor heavy rails, gates, or fence panels to posts
Stair Framing – Perfect for stringers and stair landings
General Construction – Use anywhere a strong, weather-resistant fastener is needed
The 5/16" x 4" Hex Lag Screw delivers dependable strength and holding power for demanding outdoor construction. Whether you're framing a deck or building a pergola, this lag screw is a trusted choice for structural stability and long-term durability.
Shipping, Delivery, Pick-Up, Returns & Warranty
Please review the information below before placing your order.
Shipping & Delivery
Composite Deck Shop delivers to jobsites in Ontario that are accessible to large trucks. Shipping outside Ontario is available upon request.
Orders may be shipped by flatbed truck, flatbed trailer, or pick-up truck for smaller railing and accessory orders. Smaller orders may also ship by major couriers or Canada Post. Please confirm the shipment type at the time of purchase or select an available shipping option at checkout.
Some deliveries are unloaded with a Moffett mobile forklift, while others are offloaded by hand from a flatbed. If on-site help is required, this will be noted in the delivery option selected at checkout.
Shipping rates vary based on order size, order type, and distance from one of our four Ontario locations. Prices start at $160 per order.
Material is dropped off no more than 3 metres from where the delivery truck can park. Special placement requests, such as delivery into a garage or backyard, may be available for an additional fee and require a custom quote.
Delivery timeframes
In-stock items: Next day to 7 business days, depending on the time of year and the order size and type.
Special order items: 4 business days to 14 days, depending on order type, size, and time of year. If special order material is not available through our distribution, our sales staff will advise you individually.
Pick-Up Information
All pick-ups require either an online order with pick-up available at the selected location, or approval from one of our sales representatives by phone or email.
Please do not arrive expecting immediate pick-up. We do not operate self-serve warehouses.
After an order is placed, preparation can take from 4 hours to 3 days, provided the material is in stock at the requested location. Timing depends on material quantity, material type, and time of year. A sales representative can provide an exact timeframe.
Custom cutting is available upon request for an additional cost.
Returns & Refunds
Special order material is final sale and cannot be returned or refunded.
In-stock material may be returned within 30 days of purchase if it is in original condition and in original, undamaged packaging. A 20% restocking fee applies to all returns of in-stock material.
Customers are responsible for returning material to our store or arranging pick-up at their own cost. Composite Deck Shop may take 1 to 4 business days to inspect returned material. If the material is not considered to be in original condition, no refund will be issued and the customer must pick it up. Return condition is determined at the sole discretion of Composite Deck Shop staff.
Warranty
Composite Deck Shop does not provide warranty coverage for the products it sells. Most products are covered by the manufacturer’s warranty. Customers are responsible for reviewing the manufacturer’s warranty before purchase. Composite Deck Shop is not obligated to assist with warranty issues or claims.
Please visit the Shipping, Delivery, Pick-Up, Returns & Warranty page to review all conditions.