Permit - 1295396 - Laserfiche WebLink

Home Browse Search

AUG ~9 '95 Od:28PM BUILDIMG CODES RGENCY P. 1/5 STATE OF OI~EGON BuiMing Codes Divbion Staff Advi$ory Interpretation IT he fo/lowing interpetation applies tO current code and conditions described in the question, Applications for similar situations may have different determinations. IIIIIII I II II II i PROGRAM: Energy Conservation SUBJECT: Insulation requirement for vaulted ceilings in Icg homes. SOURCE: Oregon One- and Two-Family Dwelling Specialty Code (1 & 2 FDSC) REFERENCE: 1 & 2 FDS¢, Table No. 53-P DATE OF ISSUE: August 29, 1995 REQUESTOR: Byron Miller, Log Home Supply PREPARED BY: Alan Seymour, Energy Coordinator QUESTION: Is the thermal performance for the vaulted ceiling described below for the K-3 $ requirement's specified in Table 53-P, Path 9, Vaulted Ceilings? g-inch deep logs with 3-inch flat surface for ceiling deck, 2-by ceiling deck, 15 pound felt, 2 layers of 2-inch R-lg CR.-36 total) rigid insulatiom 15 pound felt, and metal roofing. DETERMINATION: The vaulted ceiling kmulation requirement for Path 9, Table $3-P i~ R-3g. The U-value (acting/heat loss) of an R-35 vaulted ceiling is U-0.027. This value is based on 2-by-12s, placed 24 inches on center, R.3g imulafion in the cavities, 5/8" drywall, 1/2" sheathing and composition roofing. An alternate vaulted ceiling system with an effective U-value of 0,027 or less would be acceptable (energy equivalent). The spr~adsheer below denotes thermal t~rformance of the vaulted ceillng assembly as submitted by Log Home Supply. Tiffs indicates eft, clive R-value using the parallel heat loss methodology specified in the 1993 American Soeiet7 of Heating,. Refrigeration and Air-conditioning Engineers (ASHRA.E) Handbook of Fundaraentals. The U-value from the spreadsh~t applies specifically for the assembly as described: Eight-inch deep (minimum) icg miter with three inches (minimum, fiat-side) in contact wkh deck_ Two-by ceiling deck, Two.by-fours versus two-by-eight docs not make a difference. A deck with a thickness of less tha.g one and one-half inches such as a one-by.six is not acceptable. · Fi~'-een pound felt on top of the deck_ · At least two layers of two-inch thick rigid insulation with an R-value of 9 per inch or greater (R-36 total) applied over entire surface of deck. · Fifteen pound felt on top of the insulation. - Metal roof. Any type of roofing would be acceptable. Inserting nailing strips (wood two-bys) between the sheeta of insulation would not be acceptable. Post4tTM__ brand f~x transmktal memo 7671.J # ~* pa~es · ,,,2 I