Floor Sheathing

 

Two Layers

1. subfloor  (structural)
2. underlayment  (smoothness)
3. finish floor  (vinyl, ceramic, hardwood, carpet)

 

floors typically controlled by deflection under concentrated loads (how the floor feels to occupants)

 

underlayment

1. C-plugged face
2. special C inner-ply to resist indentation

1/4" over panel subfloor
3/8 or 1/2" over lumber subfloor

not required with wood strip flooring, lightweight concrete

grade stamp

 

1. strong direction
2. continuous over two or more spans
3. differential movement

• T&G
• blocking
• 1/4" underlayment with offset seams
• 1-1/2" lighweight concrete
• 3/4" wood strips

 

 

One Layer

1. combined subfloor-underlayment
2. finish floor

 

Sturd-I-Floor