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.
Caulking fiber cement siding.
It is never acceptable to leave a gap of any size at a butt end joint.
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.
Best caulk for fiber cement siding or hardiplank siding lets you have the perfect sealing your surface needs.
Butt end joints should be installed with factory sealed or factory prefinished ends butted together in moderate contact.
We only caulk butt joints on cedar siding if previously caulked.
Do not caulk fiber cement siding butt joints edges.
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.
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.
That is why we are showing you some other products for various surfaces along with our top pick.
Caulk is usually used with fiber cement siding to prevent water intrusion at the butt joints.
2 house built before 2008 so has no flashing okay to caulk.
Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur.
Sealing caulking fiber cement siding.
Big stretch acrylic latex caulking sealant by sashco.
1 i chose this caulk because it has 25 flexibility compared to silicone based caulk.
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.
Fiber cement boards are caulked only when there is no metal flashing behind them.
Butt joints however should be nailed tightly together and should not be caulked.
Trim boards wood windows.