Abstract: A portable, relocatable, erectable building or shelter structure, and method of erecting, utilizing a pair of laterally spaced elongated and segmented base rail assemblies to which are pivotally connected a pair of erectable arch assemblies for each row of a plurality of panels slidably engageable along two opposite sides to each pair of adjacent erectable arch assemblies pivotally connected to the base rail assemblies. The opposite sides of the individual panels other than the panel sides engageable to the adjacent base pivotally connected erectable arch assemblies are configured such as to be sealingly interengageable with the adjacent panel on both sides.