The disclosure generally relates to an adjustable bed foundation. The adjustable foundation includes lateral and/or longitudinal support members as part of an adjustable base frame positioned below a mattress support. The lateral and longitudinal support members, along with a fixed base frame portion of the foundation are preferably formed from a lightweight material such as wood. The lateral and longitudinal support members provide sufficient vertical support structure to accommodate a mattress and bed occupants on the adjustable platform, as well as electrical and mechanical components of the adjustable foundation below a mattress support deck.