When you try to restrict either it is at your peril.
Caulking lap siding.
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.
152 4 mm wide 1 in.
When deciding how to use caulk on your siding however it is generally more important to consider where you should not use it.
Is the old caulking removed before new coats are applied.
Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur.
If overused or incorrectly placed siding caulk can cause more damage to your exterior than good.
Caulking your home s siding is a simple process but not necessarily a foolproof one.
And many homeowners over caulk applying caulk where it doesn t belong and potentially compromising the performance of their siding.
25 4 mm on overlap no caulk figure 1.
It needs to move and breathe.
Whether you are repainting replacing a window or replacing the siding on your house the caulking around the window trim is a very important element.
How to caulk the window trim on lap siding.
Similar to paint previous coats of.
Caulk is by necessity a sticky gooey substance and as such it smudges easily.
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.
James hardie also does not recommend applying caulk to the horizontal overlap between siding planks see figure 2.
Caulk by its adhesive nature will try to limit this movement leading to widespread failure and cracking in the caulk over time.
The nails holding up the siding should not be caulked.
The siding expands and contracts with temperature and humidity.
It is generally not a good idea to use caulking on wood siding.