Joint flashing butt joint horizontal lap treatment june 2014 james hardie does not recommend caulking. Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur.
Some manufacturers do not require the metal flashing therefore we caulk the butt joint to keep the pieces together and also prevent moisture.
Do you caulk the joints of hardie board. James hardie believes it is good building practice to seal the joints to prevent moisture such as wind driven rain and snow from penetrating the wall cavity. We only caulk butt joints on cedar siding if previously caulked. James hardie also does not recommend applying caulk to the horizontal overlap between siding planks see figure 2.
The hardie board will butt against the drywall in the same plane. You need to have the best caulk for hardie siding to help your walls and wooden surfaces to get rid of open cracks and thin spaces between joints. But here the main problem is people usually don t find the right type of caulk for their works.
James hardie does not recommend using caulk or h jointers for the butt joints of hardieplank siding with colorplus technology. In photo8 i m holding a piece of hardie board and a piece of tile beside the drywall for you to see where i think they will go. With all the other hardie board joints i will finish with thinset and alkali resistant mesh tape.
If you use sashco s acrylic latex caulking sealant you can have any interior or exterior as good as new. You can use caulk on a number of areas of your hardie siding. Fiber cement boards are caulked only when there is no metal flashing behind them.
Manufacturers caulk and sealant recommendation sheet s 100b. Still you can have your criteria and so we are introducing four more products and some necessary considerations to help you in getting caulking. When putting on caulk most people decide where they want to put it.
Trim boards wood windows. 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. But in our experience we saw that both of the corners and sometimes the crevices also some butt joints door trim boards and windows are quite common areas.