Caulking Lap Siding Bottom Edge

Bottom of siding boards should not be caulked.

Caulking lap siding bottom edge.

It is generally not a good idea to use caulking on wood 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. Pull the tip of the caulk tube slowly along the joint of the window trim and the siding holding the caulk gun at a. How to caulk the window trim on lap siding 1.

Think of a wood home as a living thing. After the paint dries apply caulk and then paint the rest of the siding. When deciding how to use caulk on your siding however it is generally more important to consider where you should not use it. Scrape the side of the window trim next to the siding and the immediate edge of the lap siding with a paint scraper.

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. 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. Also avoid caulking tongue and groove siding boards together. If you prefer to caulk before painting you should still paint the cut ends first.

The bottom edge of lp lap siding is where the failure is first evident. If overused or incorrectly placed siding caulk can cause more damage to your exterior than good. It needs to move and breathe. Water is meant to exit through the bottom of each board.

Lp recommends applying primer the foundation of the house before painting the siding to prevent moisture from wicking into the siding.