Caulking Cement Fiber Siding

However this detail may not be effective at sealing the ends allowing water to be absorbed and swell the board ends.

Caulking cement fiber siding.

Both certainteed and jameshardie as of september 2008 have made clear that siding butt joint gaps should never be made that is. Fiber cement boards are caulked only when there is no metal flashing behind them. That is why we are showing you some other products for various surfaces along with our top pick. It s got good adhesion and expands and contracts.

So what i would tell you to do is to use a colored caulk to choose the caulk in the color of the 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. But you are correct that it is very difficult to paint. Flashing acts as a waterproofing layer for this type of siding and caulking will prevent the flashing from doing its job.

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. 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. Siding butt joint treatment. Big stretch acrylic latex caulking sealant by sashco.

Caulk is usually used with fiber cement siding to prevent water intrusion at the butt joints. 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. 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. What you want to use is a silicone caulk because it s the most permanent one.