Begin caulking on a dry day when you don t expect rain as rain and damp conditions can interfere with the curing process.
Caulking hardie board and batten siding.
1 i chose this caulk because it has 25 flexibility compared to silicone based caulk.
A high quality paintable caulk is recommended.
Re siding your house with hardiepanel vertical siding or combining it with hardieplank lap siding is sure to add visual punch to your design.
Fiber cement siding repair or patching.
Do not use stains or oil based alkyd paints on james hardie products.
Or go for the more minimalist look of simple vertical lines.
For best results use caulks that comply with either astm c 834 or astm c 920.
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.
Re applying caulking when it has begun to show signs of wear can help keep moisture from getting into the wall cavity.
Ensure that the board and batten siding is also dry.
For regular hardiplank lap siding the kind you paint after installation caulking at butt joints is optional.
Traditionally board and batten siding starts with wide vertical planks boards which are then joined together by thin vertical strips battens to cover the seams.
Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur.
Combine with hardietrim boards for a rustic board and batten look.
One of the main concepts of board and batten siding is to allow the boards to move under the battens and caulk would limit the ability of the system to expand and contract.
Obviously if using hardi board material allow the system to expand and contract is much less important.
Wherever hardie siding meets a trim board the company recommends you leave a 1 8 gap between the siding and the trim and apply a 3 8 bead of approved caulking to protect and seal the edge of the siding.
2 house built before 2008 so has no flashing okay to caulk.
For additional information on finishing james hardie products download technical bulletin 22 from here.