Joint Flashing For Fiber Cement Siding

A common problem with cement board siding products and some other types of horizontal lap siding is that older installation guidelines called for caulking the joint instead of flashing the joint.

Joint flashing for fiber cement siding.

Joint flashing material must be durable waterproof material that does not react with cement based products. This has proven problematic over time as caulking the joint results in unsightly surface appearances due to the different textures as well as resulted in failure of the caulk joint and associated ongoing maintenance. Coating paint means no reflective flashback as found using regular metal flashing. Junction flashing is manufactured specifically for fiber cement siding as a weather resistant barrier.

Examples of suitable material include painted or coated coil stock and code compliant water resistive barriers such as hardiewrap weather barrier. The product is a proprietary plastic 20 year uv rated sheet 4 ml thick that is basically a six by twelve post it note. As well as spray painting the flashing with a color close in color with the siding. Pre cut for quick and easy installation.

Other products may also be suitable. Coating eliminates any reaction with fiber cement. Fiber cement joint flashing the last time we used fc siding we used 3 by 5 step flashing between the joints. This h molding joint eliminates the need for caulk and has an authentic woodgrain appearance with the durability of fiber cement.

This color matched 7 1 4 inch h molding joint covers and protects butt joints and elegantly provides an expansion joint to help prevent buckling or distortion. The user friendly polyethylene flashing system is perfect for both residential and commercial siding applications. Each sheet is pre cut with a stick it adhesive for the fastest application available. Use to reduce moisture penetration behind the joint where two planks butt together and drain water over the top edge of the last full course of siding.

Junction flashing is made of 0 015 primed aluminum with an epoxy backer to protect from corrosion. Jointflash is a safe and economical solution for flashing both fiber cement and wood lap siding.