4.1301.15 Non-Joisted Floors Over Basements or Crawl Spaces (e.g., Pre-Cast Concrete, Poured in Place, Metal Deck)

Topic:

Floors

Subtopic:

Accessible Floors

Desired Outcome:

Maintain a consistent, uniform thermal and air barrier Air barrier The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary between conditioned and unconditioned space to prescribed R-value

For supporting material, see Referenced Standards.

Multifamily Homes

Title	Specification(s)	Objective(s)
4.1301.15a Subfloor preparation	Air sealing between conditioned space and unconditioned space will be completed before insulating	Ensure airtight floor assembly
4.1301.15b Metal floor decks	Bottom side of metal deck flutes will be sealed to the insulation material at every support beam joint Top side of open metal deck flutes (e.g., flutes are not filled) will be sealed to the bottom of the floor deck at every perimeter support beam joint Bottom flutes of metal decks will be totally insulated where they cross support beams from the beam to the exterior wall	Minimize air flow bypasses between insulation and metal deck subfloor Minimize condensation on underside of metal floor deck
4.1301.15c Installation	Insulation will be installed to prescribed R-value Insulation will be installed in contact with bottom of the floor decking without gaps, voids, compressions, misalignments, or wind intrusions If vapor retarders are used, they will be installed consistent with local climate/code requirements	Provide effective R-value Prevent potential fire chases Prevent excessive vapor migration into the floor assembly and/or conditioned space
4.1301.15d Installation of batts and support system	Batts will be installed continuously between structural framing Batts will be installed with a support system below the insulation Support system will be mechanically fastened to the bottom side of the floor deck	Minimize convective loops Prevent sagging Minimize gaps and voids between the insulation and floor deck
4.1301.15e Installation of rigid insulation and support system	Rigid insulation will be installed continuously between structural framing Rigid insulation will be installed with a support system below the insulation Support system will be mechanically fastened to the bottom side of the floor deck Where rigid foam plastics are used, in no case will the final thickness exceed the manufacturer's tested thickness used to determine the maximum 75 flame spread and 450 smoke-developed index when tested to ASTM ASTM ASTM International, www.astm.org E84 or UL UL Underwriters Laboratories 723 Foam will be provided with ignition and thermal boundaries, as required by code	Minimize convective loops Prevent sagging Minimize gaps and voids between the insulation and floor deck
4.1301.15f Installation of spray polyurethane foam ( SPF SPF Spray polyurethane foam )	SPF SPF Spray polyurethane foam will be applied continuously to bottom side of floor deck Where rigid foam plastics are used, in no case will the final thickness exceed the manufacturer's tested thickness used to determine the maximum 75 flame spread and 450 smoke-developed index when tested to ASTM ASTM ASTM International, www.astm.org E84 or UL UL Underwriters Laboratories 723 Foam will be provided with ignition and thermal boundaries, as required by code	Minimize convective loops Minimize gaps and voids
4.1301.15g Installation, if mechanicals are below the floor deck (applies to all insulation types)	All plumbing and ductwork will be enclosed within the insulated space and will have sufficient insulation in contact with a continuous air barrier Air barrier The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary on the exterior side	Prevent freezing of plumbing pipes
4.1301.15h Property manager education	A dated receipt signed by the installer will be provided that includes: Coverage area Thickness R-value	Document job completion to contract specifications Confirm amount of insulation installed Comply with 16 CFR 460.17