Composite decking requires a solid foundation or substructure for support. This base is typically a frame composed of posts, beams, joists, and footings. The frame can be built from various materials, such as composite, plastic, timber, or metal, depending on your budget, deck type, and environmental conditions. For maximum stability, a professional deck builder may recommend installing this frame on top of a solid concrete base. It is best to discuss the most suitable substructure design and materials for your specific project with a professional.

The least expensive way to build a pool deck is with concrete deck blocks, pressure-treated lumber, and the appropriate hardware for hanging joists and securing deck boards. With these basic yet durable deck materials, you'll have a pool deck that's built to last without the high price tag. You should also stain or seal the deck to protect it against the elements.

No, termites do not eat Trex or any other composite decking brand. Termites eat cellulose, of which composite decking like Trex contains very little compared to natural wood. This feature can help justify the higher Trex decking costs if you live in an area with abundant termites.

For a 12x20-foot (240-square-foot) deck, you can expect to pay between $7,200 and $14,400. This cost is based on a general price of $30 to $60 per square foot. The final price will depend on factors such as the decking material, design complexity, deck type, location, and local labor costs. Keep in mind that add-ons will increase the total; for example, adding an under-deck drainage system to a deck of this size could cost an additional $7,700.