Caulking Lap Siding Bottom Edge

Garage door panels should not be caulked.

Caulking lap siding bottom edge.

Designed to let water out of your windows these small openings should never be. The siding expands and contracts with temperature and humidity. Trim boards that sit on top the siding. One way to prolong the useful life of the siding is to keep it well maintained.

It needs to move and breathe. The corner boards and the ends of the siding are nailed to the corner studs which anchors the wood for a maintenance free joint. Caulking at hardieplank lap siding butt joints is not recommended for colorplus for aesthetic reasons as the caulking and colorplus will weather differently. The panel siding tends to do better than the lap siding because there is no drip edge for water to cling to.

All penetrations such as over driven fasteners and site cut edges of siding need to be sealed with caulk and paint. Window weep hole should not be caulked. While a diyer or a novice painter might attempt to produce a cleaner look by. 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.

Refer to the colorplus touch up section for details do not use caulk on hardieplank lap siding with colorplus technology. The bottom edge of lp lap siding is where the failure is first evident. Corner boards are applied to the sheathing with siding fitting tightly against the narrow edge of the boards allowing for expansion and an adequate caulking bead. For the same reason do not caulk exposed nail heads.

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. The worst failure we have seen yet.