Composite cladding, made from a blend of wood fibre and plastic, is a popular low-maintenance exterior cladding option that combines the appearance of natural timber with the durability and weather resistance of a composite material. Installation is straightforward for a competent DIYer, and this guide covers the main steps.

Planning and Preparation

Before installation, confirm whether planning permission is required. In conservation areas or for listed buildings, cladding an exterior wall requires planning permission or listed building consent. For most standard residential properties, cladding is permitted development. Check the planning position before purchasing materials.

Calculate the required quantity of cladding boards from the wall area to be clad, adding ten percent for cutting waste. Order the manufacturer's recommended fixings, trims, starter strips, and corner profiles at the same time. Composite cladding boards expand and contract with temperature changes, so all gap dimensions should follow the manufacturer's specification.

Batten Framework

Composite cladding is not fixed directly to the wall; it is fixed to a framework of treated timber or aluminium battens that provide a flat, true surface and a ventilated cavity behind the cladding. The ventilated cavity is important to allow moisture to escape and prevent condensation building up behind the boards. Battens are typically 50mm by 25mm or 50mm by 38mm treated softwood or purpose-made aluminium cladding battens. Fix the battens horizontally to the wall at the centres specified by the cladding manufacturer, typically 400 to 600mm, using appropriate wall fixings and ensuring they are level and in the same plane.

Installing the Starter Strip and First Board

Fix the starter strip along the bottom of the wall at the correct height to achieve the desired finish level and overhang at the bottom. The starter strip engages with the bottom edge of the first cladding board and sets the angle. Fix the first board onto the starter strip, ensuring it is level, and fix its top edge to the battens with the manufacturer's specified clips or face fixings.

Laying Subsequent Boards

Clip or fix each subsequent board in the same way, working upward. Most composite cladding systems use hidden clips that fix the top edge of each board to the batten and also engage with the bottom edge of the board above, providing a secure and concealed fixing with consistent joint widths. Leave all end gaps and butt joints at the recommended dimension to allow for thermal expansion. Cut boards at window and door reveals using a fine-tooth saw.

Corner Profiles and Trims

Finish external corners with the manufacturer's corner profiles, which provide a clean junction and allow the boards to expand independently on each face. Fit window and door trims around openings before the cladding boards reach each reveal, ensuring the trim is sealed to the window or door frame with a compatible flexible sealant.

Summary

Composite cladding is installed on a treated timber or aluminium batten framework with a ventilated cavity behind. Work from the bottom upward, engaging each board with the hidden clip system and maintaining the manufacturer's specified expansion gaps. Finish corners and reveals with proprietary profiles and trims. Follow the manufacturer's specific installation guide throughout.