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.
Because they penetrate the surface of the concrete, stains produce permanent color that is UV stable. This means that most stains can be used outdoors without fading. Stains are limited in that they are semi-transparent, meaning they wonât hide existing blemishes or patchwork. Cost: $5-10 per square foot.