Overview of Perlite Roofdeck Applications

ROOF INSULATION

Perlite concrete roof deck insulation is an ideal base for built-up and single-ply roofing systems. It has superior wind and fire resistance over other roof insulation materials and with the addition of polystyrene insulation board sandwiched in the perlite concrete, high thermal resistance values, are economically achieved.

Positive drainage is easily accomplished by varying the thickness of perlite concrete or by stair stepping different thicknesses of polystyrene insulation board and then covering it with a uniform layer of perlite concrete.

Perlite concrete insulation may be placed over vented or slotted galvanized steeldecking, precast or poured-in-place concrete, or existing roofing materials providing a seamless, smooth, and hard surface ready for roofing. If exposed to water it will not deteriorate.

REROOFING BASE

Perlite concrete insulation is ideally suited for reroofing applications. It provides permanent, cost effective, slope-to-drain designs with high R-values over flat and often-irregular substrates found in reroofing projects. Using a perlite concrete slurry coat, the polystyrene insulation board is positively attached to the substrate and covered with a uniform layer of perlite concrete insulation. If the existing substrate is sound and capable of the additional loading required, then the perlite concrete insulation can be applied to the existing roof thereby eliminating costly tearoffs.

TESTING AND APPROVALS

Perlite roof deck insulation systems have been tested and approved for wind and fire ratings by Underwriters Laboratories, Factory Mutual, and other code authorities. The system is rated as non-combustible by Factory Mutual. U.L. Design P-920 successfully achieved the first 2-hour rating for any system of this kind under full scale fire conditions. Perlite concrete roof decks with polystyrene insulation board meet criteria for U.L. Class 90 and FM 190 wind resistance.

TABLES AND DIAGRAMS

Table 1 - Conversion Factors I-P to SI Units
Table 2 - R-Value, U-Factor, and Deadload Table
Table 3 - U.L Fire Rated Systems
Table 4 - Typical Physical Properties and Mix Proportions for Perlite Concrete

Diagram 1 - Typical Built-Up Roof Cross-Section

CODE APPROVALS AND GUIDE REFERENCES

International Conference of Building Officials (ICBO)
Building Conference of America (BOCA)
Southern Building Code Congress (SBCC)
South Florida Building Code
Ferderal Construction Guide Specification FCGS 03501
U.S. Army Corps of Engineers Guide Specificatoins: CEGS 03510

TECHNICAL SUPPORT

FM I-90 Wind Uplist
FM Serial Report No. OC2AO-AC
U.L. Wind Uplift Construction No. 143
U.L. Wind Uplift Construction No. 250
U.L. Fire Rated Designs
Ask your perlite supplier or contact: The Perlite Institute

Information given herein is from sources considered reliable, but no guarantee of accuracy can be made or liability assumed. Your supplier may be able to provide you with more precise data. Certain compositions or processes involving perlite may be the subject of patents.
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