Undercoat with a high VOC content, like Dulux Trade Undercoat, can be applied using a brush or roller, and it's suitable for both indoor and outdoor applications. This undercoat typically dries to the touch within 2-6 hours and can be recoated after 6-16 hours.

For optimal results, it's important to make sure that the surfaces you plan to paint are in good condition, clean, and dry. This is especially crucial for new surfaces, which must be completely dry before painting. Additionally, ensure that the surfaces are free from any defects or poorly adhering materials like dirt, grease, or wax. If you're working with new or bare surfaces, it's important to apply the appropriate primer before using the undercoat.