Caulking Cement Fiber Siding

Natural siding boards are designed to expand and contract with the elements and we do not want any adhesive to prevent their natural movement.

Caulking cement fiber siding.

Flashing acts as a waterproofing layer for this type of siding and caulking will prevent the flashing from doing its job. When james hardie siding products butt into wood based materials a 1 8 gap will allow for expansion and contraction of the wood based product. Both certainteed and jameshardie as of september 2008 have made clear that siding butt joint gaps should never be made that is. However this detail may not be effective at sealing the ends allowing water to be absorbed and swell the board ends.

What you want to use is a silicone caulk because it s the most permanent one. Best caulk for fiber cement siding or hardiplank siding lets you have the perfect sealing your surface needs. Fiber cement boards are caulked only when there is no metal flashing behind them. Caulk is usually used with fiber cement siding to prevent water intrusion at the butt joints.

Siding butt joint treatment. Many professionals like those at james hardie also agree that you should not use caulk on fiber cement siding unless there is no metal flashing underneath. But you are correct that it is very difficult to paint. The following information is adapted expanded a bit from certainteed corporations installation instructions for the company s fiber cement siding products as this is the most comprehensive guide we could find for caulking clearance instructions when installing fiber cement siding.

Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur. So what i would tell you to do is to use a colored caulk to choose the caulk in the color of the siding. It s got good adhesion and expands and contracts. Do not deliberately leave butt joint gaps in fiber cement lap siding and that they do not recommend caulking field cut butt joints in their board type fiber cement siding products.