Caulking Lap Siding

While paint does tend to somewhat glue these pieces together caulking them is never advised and can cause permanent damage.

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. Caulking at the horizontal overlaps is not recommended because it impedes these drainage and drying mechanisms inherent to lap siding. Pull the tip of the caulk tube slowly along the joint of the window trim and the siding holding the caulk gun at a. It needs to move and breathe.

Caulk is by necessity a sticky gooey substance and as such it smudges easily. The fundamental principle of water management is to shed water by layering materials in such a way that water is directed downwards and outwards out of the building or away from the building. And many homeowners over caulk applying caulk where it doesn t belong and potentially compromising the performance of their siding. Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur.

How to caulk the window trim on lap siding 1. Create a proper 3 16 space at minimum between the two pieces of siding. Slide a piece of metal sheeting behind the butt joint. The siding expands and contracts with temperature and humidity.

Caulking them is a mistake and the caulking is likely to fail prematurely. Bottom of siding boards should not be caulked water is meant to exit through the bottom of each board. Use a keyhole or reciprocating saw with a fine tooth blade to remove enough material from one of the pieces of lap siding. Scrape the side of the window trim next to the siding and the immediate edge of the lap siding with a paint scraper.

In my opinion caulking between the seams in any lapped siding either horizontal or vertical is not good practice but not just because of any potential vapor barrier effect. When to use caulk on exterior siding siding caulk can be used on several different areas of your exterior siding to help prevent water damage and moisture buildup.