Cast Stone was first developed about 800 years ago but it did not get widespread use in residences until the 1920’s.
The main benefits of cast stone is the ability to provide a natural stone feel with intricate details as found on fireplace mantles while keeping the cost down.
Castings can be made for everything from decorative lamps, Countertops, and Architectural Details used both inside and outside but the pieces themselves can not be made as a structural piece to support other parts of a wall or building.
Casting mixes include Natural Stone, Portland Cement and water.
Pieces are manufactured either by stamping or poured into molds.
Items that are wet cast in molds can contain color through out the piece or may have a surface color and texture that can make the part more susceptible to damage and delamination.
Veining of the surface is accomplished by placing colors into the mold before it is filled with the stone cast material.
The strongest Cast Stone will have aggregates of various sizes so they fit together closely in the mold with the Portland Cement holding them together and filling the voids.
Cast stone is available in natural or custom colors to match your decor. Along with Cement Stains you can select a number of base aggregates that will give you the appearance of stone.
Surface textures can be everything between the texture found in the mold to saw marks and high polish.
Various techniques are used to prepare the surface with the same tools that are used in natural stone work. Hand polishing and tooling of the piece is possible but machine tools will get the job done quicker.
Acid wash is another technique that can be used on pieces that have uniform color mixtures. You would not want to acid wash a piece that only has surface colorants unless you test your work and understand the strength of the acid you are applying.
Care and restoration
Cast stone should be cared for much in the same way as you would natural stone or concrete counter tops.
Weather can cause quick damage and delaminaton. Water that penetrates the surface will cause spauling during freezing conditions and acid rain will change the ph level of the Cement causing it to break down.
Metal rebar used within the piece can also cause spauling when it begins to oxidize. Moisture is a man cause.
Sealers can increase the life of cast stone and should be applied as recommended depending on the final finish of the part.