Caulking Split In Siding Joints

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

Caulking split in siding joints.

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

The surface must be clean of dust and chalky paint. Clean the hole or depression you plan to fill. A high quality paintable caulk is recommended. 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.

Your house s siding naturally expands and contracts and caulking it all together prevents this movement. If the siding joint is so tight that the caulk only bridges the gap it may split again. Caulking them is a mistake and the caulking is likely to fail prematurely. This is where the siding in the middle of the wall butts up against another piece of siding.

So just to review. Water can seep in around butt joints and trim so these areas need to be caulked. A caulk must be high quality in order to have the elasticity and adhesion necessary. Roughen the area you want to patch with 80 grit sandpaper for a better bond.

For regular hardiplank lap siding the kind you paint after installation caulking at butt joints is optional. Apply the compound to the hole or depression in one direction. You can also use caulk to repair cracks in your siding. These siding joints can be caulked successfully if the gap is wide enough for the caulk to get into the crack.

Sometimes the old caulk in the siding joint is cracked and you need to cut the old caulk out with a razor knife. To patch holes and depressions in siding of any kind follow these steps. Do not caulk the underside of your siding i e caulk each piece of siding to the one beneath it. This from installation instructions.

Sometimes the old caulk must be razor cut from these butt joints. 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. For best results use caulks that comply with either astm c 834 or astm c 920. 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.

Another critical place is where the siding butts together in the middle of the wall.