There are three principal layers; 1  External intercostal muscles aid in quiet and forced inhalation. They originate on ribs 1-11 and have their insertion on ribs 2-12. 2  Internal intercostal muscles aid in forced expiration (quiet expiration is a passive process).
Costs. A professional concrete contractor will typically charge $2-$4 per square foot for a simple stain application, including the sealer. A stain application with patterning and sawed lines will typically cost between $4 and $10 per square foot.
polishing. Basic cost for a polished concrete floor up to a 800 grit: $3.00 per square foot. Cost for polished concrete floors requiring decorative scoring and/or staining: Up to $8.00 per square foot. For large commercial floors, may include staining and decorative scoring: From $3.00 - $7.00 per square foot.