Caulking Cement Fiber Siding
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.
Caulking cement fiber siding. 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. So what i would tell you to do is to use a colored caulk to choose the caulk in the color of the siding. Flashing acts as a waterproofing layer for this type of siding and caulking will prevent the flashing from doing its job. What you want to use is a silicone caulk because it s the most permanent one.
It s got good adhesion and expands and contracts. Fiber cement boards are caulked only when there is no metal flashing behind them. Best caulk for fiber cement siding or hardiplank siding lets you have the perfect sealing your surface needs. 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.
That is why we are showing you some other products for various surfaces along with our top pick. Both certainteed and jameshardie as of september 2008 have made clear that siding butt joint gaps should never be made that is. We only caulk butt joints on cedar siding if previously caulked. Big stretch acrylic latex caulking sealant by sashco.
Siding butt joint treatment. Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur. However this detail may not be effective at sealing the ends allowing water to be absorbed and swell the board ends. Caulk is usually used with fiber cement siding to prevent water intrusion at the butt joints.