Starting off square and level is essential to a successful shed assembly and we recommend that you consider a base kit to self-square the shed and help level the site. Base kits are available for the majority of Arrow sheds. The base kit must be assembled with your selected floor finishing option before you start to build your shed. Use the flooring material that best suits your needs, such as wood, patio blocks, or gravel. The base kit may also be used as a form for pouring concrete. Find the base kit size for your shed.