Caulking Split In Siding Joints

The alternative is to use a joint molding in place of caulk.

Caulking split in siding joints.

Siding caulk can be used on several different areas of your exterior siding to help prevent water damage and moisture buildup. 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. So just to review. While paint does tend to somewhat glue these pieces together caulking them is never advised and can cause permanent damage.

Caulking them is a mistake and the caulking is likely to fail prematurely. These siding joints can be caulked successfully if the gap is wide enough for the caulk to get into the crack. Apply the compound to the hole or depression in one direction. Roughen the area you want to patch with 80 grit sandpaper for a better bond.

Do not caulk the underside of your siding i e caulk each piece of siding to the one beneath it. Clean the hole or depression you plan to fill. This is where the siding in the middle of the wall butts up against another piece of siding. 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.

The surface must be clean of dust and chalky paint. Sometimes the old caulk must be razor cut from these butt joints. Your house s siding naturally expands and contracts and caulking it all together prevents this movement. This allows for the caulk to get in and fill the gap correctly.

This from installation instructions. 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. Bottom of siding boards should not be caulked water is meant to exit through the bottom of each board. To patch holes and depressions in siding of any kind follow these steps.

A caulk must be high quality in order to have the elasticity and adhesion necessary. A high quality paintable caulk is recommended. Water can seep in around butt joints and trim so these areas need to be caulked. Another critical place is where the siding butts together in the middle of the wall.

For best results use caulks that comply with either astm c 834 or astm c 920. 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. Fill the area with patching compound. If the siding joint is so tight that the caulk only bridges the gap it may split again.

For regular hardiplank lap siding the kind you paint after installation caulking at butt joints is optional.