While paint does tend to somewhat glue these pieces together caulking them is never advised and can cause permanent damage.
Caulking split in siding joints.
This allows for the caulk to get in and fill the gap correctly.
Bottom of siding boards should not be caulked water is meant to exit through the bottom of each board.
Caulking them is a mistake and the caulking is likely to fail prematurely.
Siding caulk can be used on several different areas of your exterior siding to help prevent water damage and moisture buildup.
The surface must be clean of dust and chalky paint.
Clean the hole or depression you plan to fill.
Apply the compound to the hole or depression in one direction.
You can also use caulk to repair cracks in your siding.
Sometimes the old caulk must be razor cut from these butt joints.
For regular hardiplank lap siding the kind you paint after installation caulking at butt joints is optional.
Do not caulk the underside of your siding i e caulk each piece of siding to the one beneath it.
A high quality paintable caulk is recommended.
A lot of moisture from rain snow misdirected sprinklers or exuberant water fights can get in there enough to do some serious and expensive damage.
This from installation instructions.
This is where the siding in the middle of the wall butts up against another piece of siding.
For best results use caulks that comply with either astm c 834 or astm c 920.
A caulk must be high quality in order to have the elasticity and adhesion necessary.
The alternative is to use a joint molding in place of caulk.
Butt joints are a perfect example of poor joint design they re too small to accommodate a bond breaker so the caulk can t stretch properly once applied but they re also too large to simply leave alone.
To patch holes and depressions in siding of any kind follow these steps.
So just to review.
Some of the most commonly caulked areas of siding include both corners and crevices as well as some butt joints and window and door trim boards.
These siding joints can be caulked successfully if the gap is wide enough for the caulk to get into the crack.
Water can seep in around butt joints and trim so these areas need to be caulked.
Fill the area with patching compound.
Your house s siding naturally expands and contracts and caulking it all together prevents this movement.
A gap of 1 8 of an inch to 3 8 of an inch is necessary for the caulk to get into the crack and produce a good joint.
It depends on the option you choose but if joint caulking option is selected seal all gaps at butt joints with a high quality exterior sealant meeting the astm c920 minimum class 25 sealant.
If the siding joint is so tight that the caulk only bridges the gap it may split again.
