Caulking Hardie Lap Siding

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.

Caulking hardie lap siding.

Hardie no longer recommends the caulking of any joint in their lap siding colorplus or primed. Deterioration of the caulking in the joint has become a maintenance issue for home owners over time. 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. Lasalle st suite 2000.

James hardie fiber cement siding best practices appendix a 2014 pdf available from james hardie corporation 231 s. James hardie hardiplank lap siding installation instructions pdf 2001 jameshardie corp 26300 la alameda suite 250 mission viejo ca 92691. We need air circulation behind these boards and the opening acts as a water exit should water ever go behind the boards. On most new homes the trim goes up after the siding is installed which creates a large gap that should not be caulked.

James hardie also does not recommend applying caulk to the horizontal overlap between siding planks see figure 2. Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur. 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. Butyl rubber is sometimes recommended for exterior siding since it s a specialty outdoor caulk that can withstand changes in temperature and repeated exposure to the elements but you can choose any exterior caulk that will bond to your siding just make sure to read the labels and spot check on an unseen portion of your siding to make sure.

25 4 mm on overlap no caulk figure 1. 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. In the old days the builder would install the trim bring the siding up to it and caulk the corner. Joint flashing is recommended for all hardie lap siding now.