Metal spikes make fixing the base to the ground a very simple procedure, and using a base should ensure that the shed is level. the timber base is made from high quality, pressure treated softwood - that's why it is guaranteed against rot for 15 years.. Product description. making sure that the wooden shed you have just purchased is level and, so that air can circulate, does not rest directly on the ground, should be a prime consideration, that is why it is worth checking out a forest timber shed base.. See more like this forest timber shed base 5 x 3 with metal spikes. forest timber shed base 7 x 5 wooden with metal spikes. brand new.