Caulking Lap Siding Bottom Edge

Designed to let water out of your windows these small openings should never be.

Caulking lap siding bottom edge.

All penetrations such as over driven fasteners and site cut edges of siding need to be sealed with caulk and paint. The bottom edge of lp lap siding is where the failure is first evident. The siding expands and contracts with temperature and humidity. 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. 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. For the same reason do not caulk exposed nail heads. The worst failure we have seen yet.

The corner boards and the ends of the siding are nailed to the corner studs which anchors the wood for a maintenance free joint. Garage door panels should not be caulked. Caulk across the top edge of the siding where it meets the top of the wall around windows and doors across the bottom edge of the siding where it meets the foundation and any other area where gaps exist. The panel siding tends to do better than the lap siding because there is no drip edge for water to cling to.

While a diyer or a novice painter might attempt to produce a cleaner look by. Caulking at hardieplank lap siding butt joints is not recommended for colorplus for aesthetic reasons as the caulking and colorplus will weather differently. Think of a wood home as a living thing. Window weep hole should not be caulked.

It needs to move and breathe. Trim boards that sit on top the siding.