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.
How much does an average concrete overlay cost? A. Concrete overlays vary in cost. A thin microtopping that is applied at no more than an 1/8 of an inch can cost anywhere from $3 to $5 per square foot installed. If you go with a decorative microtopping the cost depends how much detail is in the work.