Caulking Fiber Cement Siding

We only caulk butt joints on cedar siding if previously caulked.

Caulking fiber cement siding.

Butt joints however should be nailed tightly together and should not be caulked. Do not caulk fiber cement siding butt joints edges. 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. Placing caulk over large portions of wood siding prohibits the natural movement of the wooden panels and can cause extensive damage to the exterior of your home.

How were butt joints and end joints treated flashed caulked. Some manufacturers do not require the metal flashing therefore we caulk the butt joint to keep the pieces together and also prevent moisture. However this detail may not be effective at sealing the ends allowing water to be absorbed and swell the board ends. Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur.

Cut ends of fiber cement siding should have been sealed using 100 acrylic latex primer or paint certainteed or in some cases using an approved caulk wiped on the cut surface see our notes on hardieplank installation. 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. Big stretch acrylic latex caulking sealant by sashco.

It is never acceptable to leave a gap of any size at a butt end joint. 1 i chose this caulk because it has 25 flexibility compared to silicone based caulk. 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. Trim boards wood windows.

Fiber cement boards don t expand and contract much but leave a little room for expansion at the end joints and then fill the gap with caulk. 2 house built before 2008 so has no flashing okay to caulk. Best caulk for fiber cement siding or hardiplank siding lets you have the perfect sealing your surface needs. Sealing caulking fiber cement siding.