15 x 120 x 3900mm Softwood Shiplap Tongue & Groove is a precision-machined timber profile designed for exterior wall cladding, weatherboarding, and garden building construction.

 

• Shed & Garden Room Cladding: Creates a weather-tight outer protective skin for garden sheds, summerhouses, home offices, and workshops.

• Exterior Wall Covering: Installed horizontally onto vertical timber battens to clad garage walls, house extensions, or outbuildings.

• Garden Structures & Screening: Used to construct durable timber fencing, trash bin enclosures, log stores, and privacy screening.

• Refurbishment & Repairs: Ideal for replacing worn, damaged, or rotting weatherboards on existing outdoor timber structures.

Available for collection from our Rugby branch or local delivery using our own fleet.

Delivery is kerbside and the final offloading position is always subject to safe access and the driver’s discretion.

Please tell us before delivery about:

• Narrow roads or restricted entrances
• Parked vehicles or limited turning space
• Overhead cables, trees or other obstructions
• Soft, sloping or unsuitable ground
• Any other access concerns

Enter your postcode on the product page to check your delivery area. We’ll confirm the delivery date after your order is placed.

Is this untreated softwood board suitable for outdoor use?

Untreated softwood requires a suitable exterior protective finish—such as an exterior wood preservative, paint, stain, or clear seal—prior to or immediately after installation. This protects the wood fibers from fungal decay, rot, and moisture damage caused by weather exposure.

How does the shiplap profile shed water?

The shiplap design features a overlapping joint combined with a scalloped rebate. When mounted horizontally, rainwater naturally flows down the face of the cladding and channels off the board away from the joint, keeping the building interior dry.

How should this cladding be installed and fixed?

Mount the boards horizontally onto vertical treated timber battens spaced at 400mm to 600mm centers. Use stainless steel or hot-dipped galvanized fixings to prevent rust bleed, driving nails through the face just above the rebate rather than directly through the tongue.

What is the benefit of the tongue and groove joint over standard overlap cladding?

The interlocking tongue and groove joint provides superior dimensional stability, alignment, and structural strength compared to simple overlap boards. It helps prevent wind-driven rain penetration and reduces board twisting over time.

How do I calculate the coverage for a cladding project?

Each 3900mm length gives roughly 0.43 m² of usable coverage (calculated using the 110mm visible face width). Divide your total surface area in square meters by 0.43 and add 10% extra to cover cutting waste and end-trimming.