Section 1917 Lightweight Insulating Concrete Roofs

The permit holder shall make available to the building official a job log with the following minimum items.

1. Cast density recordings/hour.
2. Product evaluation for application.
3. Date and job locations identified.
4. Results of any field test conducted.

Lightweight insulating concrete shall be poured over bottom slotted galvanized (G-90) steel decking as follows; cellular, 0.5-percent open; hybrid, 0.75-percent open, aggregate, 1.5-percent open. No lightweight insulating concrete shall be poured over a painted or nongalvanized steel deck.

1. Lightweight insulating concrete over structural concrete slabs, twin tees, precast units or other nonventing substrates shall be vented to allow the escape of excess moisture.

The lightweight insulating concrete fastener withdrawal shall have a minimum resistance for new pours of:

1. 60 pounds (267 N) in 28 days when the fastener is installed and allowed to age in the concrete.
2. 40 pounds (178 N) at time of roofing.

Insulation board with lightweight insulating concrete shall conform to Type I expanded polystyrene insulation as defined in ASTM C578.

1. Packaged insulation board delivered to the job site shall comply with the provisions of Section 2603.2.
2. Installation of insulating board in conjunction with lightweight insulating concrete shall comply with uplift requirements set forth in Section 1609 (Section 1620 for the High-Velocity Hurricane Zone). Insulation panels shall be placed in a minimum ¹/₈-inch (3.2 mm) slurry of insulating concrete while the material is still in a plastic state. The insulating concrete shall be cast over the insulation boards according to the insulating concrete manufacturer's product approval. Insulation panels shall be provided with holes and/or slots for keying and venting.