Don Vandervort, Head Homeboy, has written more than 30 DIY home improvement books, been a segment host on HGTV, served as MSN.com's home improvement expert and written countless magazine articles.
Composite decking is a great alternative to traditional wood decking, but does have some limitations. Composite decking can not be used as structural material. This means that any load bearing area will need to be framed and supported before the composite material can be attached.
When building your deck and railing, it is recommended that pressure treated wood be used as the framing and floor joists. This wood is protected against the elements and insects and will provide a solid support for your decking material.
Be sure to check with the manufacturers instructions when planning the substructure of your composite deck--proper sizing and spacing of beams and joists is essential.