The durability of your play set depends for a great deal on the timber you choose. We recommend pinewood, either naturally resistant to wood-rot and insect damage or pressure treated.
The quantity of the timber depends on the available widths and lengths at your retailer. Due to the content of the hardware package you have the possibility to use timber dimensions to suit your wishes/requirements for building a sturdy climbing frame. To build a safe play set the measurements should be within the margins given.
Make sure to check your timber for the absence of large knots. We also recommend buying on four sides sanded and planed beams and boards.