Caulking Lap Siding Bottom Edge

The bottom edge of lp lap siding is where the failure is first evident.

Caulking lap siding bottom edge.

Lp recommends applying primer the foundation of the house before painting the siding to prevent moisture from wicking into the siding. 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. Lp siding products also come in sheets in when water runs down the face of the siding it tends to hang on the bottom edge wicking up and causing the bottom edges to swell and delaminate. How to caulk the window trim on lap siding 1.

Pull the tip of the caulk tube slowly along the joint of the window trim and the siding holding the caulk gun at a. The siding expands and contracts with temperature and humidity. Scrape the side of the window trim next to the siding and the immediate edge of the lap siding with a paint scraper. It is generally not a good idea to use caulking on wood siding.

After the paint dries apply caulk and then paint the rest of the siding. The worst failure we have seen yet. Also avoid caulking tongue and groove siding boards together. If you prefer to caulk before painting you should still paint the cut ends first.

If overused or incorrectly placed siding caulk can cause more damage to your exterior than good. It needs to move and breathe. While paint does tend to somewhat glue these pieces together caulking them is never advised and can cause permanent damage. Think of a wood home as a living thing.

Bottom of siding boards should not be caulked.