Caulking Fiber Cement Siding

Placing caulk over large portions of wood siding prohibits the natural movement of the wooden panels and can cause extensive damage to the exterior of your home.

Caulking fiber cement siding.

Dap alex plus 12 pack 10 1 oz white paintable latex caulk. Flashing acts as a. Natural siding boards are designed to expand and contract with the elements and we do not want any adhesive to prevent their natural movement. Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur.

Most fiber cement manufacturers make mounting blocks for lights electrical receptacles a c lines pvc venting etc. Big stretch acrylic latex caulking sealant by sashco. 1 i chose this caulk because it has 25 flexibility compared to silicone based caulk. Fiber cement boards are caulked only when there is no metal flashing behind them.

Item 157140 model 11532. In my experience water that gets trapped against fiber cement siding can be absorbed by the material causing joints to swell and shrink during freeze thaw cycles. We only caulk butt joints on cedar siding if previously caulked. Instead we snug the joints up tight and.

A mark parlee a general contractor in des moines iowa responds. The following information is adapted expanded a bit from certainteed corporations installation instructions for the company s fiber cement siding products as this is the most comprehensive guide we could find for caulking clearance instructions when installing fiber cement siding. They re cheaper and easy to install and you can cut the proper size hole in a plastic mounting block with a utility knife or a snips. Jaime prefers to use the vinyl mounting blocks typically used with vinyl siding.

On our jobs we typically don t leave gaps for caulk at butt joints because this detail can contribute to the problem. Many professionals like those at james hardie also agree that you should not use caulk on fiber cement siding unless there is no metal flashing underneath. 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.