[header] How to install cement board soffit panels [title] Choose the product you wish to install. [step] Soffit and ceiling cement board products are available from a number of manufacturers and have a variety of surface finishes. You can research these at building product retailers, lumber and building supply stores, and larger home improvement warehouses. 
Here are some things to consider : [substeps] Dimension. Sheets can be in various sizes, from 12 inch (30 cm) widths to 48 inch (121 cm), and in lengths up to twelve feet (3.6 meters).