Building fixing and supporting structure

The utility model provides a building fixing and supporting structure which comprises a thin-wall steel joist base body, the lower portion of the thin-wall steel joist base body is connected with a concrete base body, the upper portion of the thin-wall steel joist base body is connected with a first cement pressure plate, and the face, connected with the thin-wall steel joist base body, of the first cement pressure plate is provided with reticulate patterns. An anti-corrosion wood keel is arranged on the upper portion of the first cement pressure plate, an XPS heat preservation plate is embedded in the grid, a second cement pressure plate is arranged above the anti-corrosion wood keel, a layer of steel wire mesh is laid at the joint of the second cement pressure plate and the anti-corrosion wood keel, and an SBS modified asphalt waterproof coiled material is laid on the upper portion of the second cement pressure plate. A bonding mortar layer is laid on the SBS modified asphalt waterproof coiled material, and