Description and usage
Squared stones were stones (often quarried from the bedrock) that were cut square so that they could be laid one on another to form a wall or building.
Translation
The size of building stones varied considerably, from stones that could be lifted by a man to some which were several meters long and weighed many tons. Translators should avoid a word that means simply bricks or small stones. We may say “very large stones that have been cut into square blocks.”

Normally it is not necessary to translate such an unsure term with great architectural precision, and for the whole verse it will be preferable to follow a version like CEV, which says “From the foundation all the way to the top, these buildings and the courtyard were made out of the best stones carefully cut to size, then smoothed on every side with saws,” or NCV, which has “All these buildings were made with blocks of fine stone. First they were carefully cut. Then they were trimmed with a saw in the front and back. These fine stones went from the foundations of the buildings to the top of the walls. Even the courtyard was made with blocks of stone.”
