Caulking Hardie Lap Siding

Trim boards that sit on top the siding.

Caulking hardie lap siding.

Optionally install the lap siding with a maximum 1 8 gap and caulk the joint see detail at right. This video is about how to like a pro. James hardie also does not recommend applying caulk to the horizontal overlap between siding planks see figure 2. Install hardiplank siding with joints butted in moderate contact.

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. Hardie no longer recommends the caulking of any joint in their lap siding colorplus or primed. In the old days the builder would install the trim bring the siding up to it and caulk the corner. 152 4 mm wide 1 in.

The first course of any wall should be installed over a 1 4 lath strip to ensure a consistent plank angle see figure 1. Joint flashing is recommended for all hardie lap siding now. Deterioration of the caulking in the joint has become a maintenance issue for home owners over time. It s also recommended to use a cloth or rag ready to wipe up and smooth excess caulking before it sets on the siding what should never be caulked.

25 4 mm on overlap no caulk figure 1 figure 2 9. Joint flashing butt joint horizontal lap treatment june 2014 james hardie does not recommend caulking butt joints or the horizontal overlaps joint flashing 6 in. 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 around windows doors eaves and trim edges gives added insurance that leaks will not occur.