Construction Estimating Formulas & Useful Information

Cord Wood:

 A cord of wood measures 4' x 4' x 8'.  Stacked cord contains 128 cubic feet by measure.  Actually is 80 cubic feet -the rest is air.
Weighs 3,000 pounds when dry, 4,000 pounds when wet. Seasoned wood is defined as having 25% moisture content.  Four percent of its energy is lost in the evaporation process as it burns.  Green wood is defined as having 80% moisture content.  Fifteen percent of its energy is lost in the evaporation process.

Fuel energy BTU comparison:

Heating Oil	138,000 BTU per gallon (number 2 fuel oil)
Natural Gas	100,000 BTU per therm
L P gas	93,000 BTU per gallon
Mixed Hardwood	8,600 BTU per pound based on seasoned wood weighing +/- 3,000 pd. per cord.  24,000,000 BTU per cord (+/-)

Electrical formulas:  1.  Amps = Watts / Volts
                                     2.  Watts = Amps x Volts
                                     3.  Volts = Watts / Amps

Insulation:  The R-value of materials measures its resistance to heat flow.  The higher the R value, the better the resistance to heat flow.
                 The U-value is used to calculate heat loss.
Formula to find U-value is:  1 / R - value = U - value.

R-values of some common building materials:

1" Fiberglass batt, Insulation	3.17		1" Expanded polystyrene	4.00		1" Extruded polystyrene	5.0
1" Polyisocyanurate, foil-faced	7.20		8" concrete block	1.11		1' Poured concrete	0.08
1" Soft wood lumber	1.25		2x4 kds	4.38		2x6 kds	6.88
1/2" plywood	0.63		3/4" plywood	0.94		1/2" gypsum board	0.45
Window with single glass	0.91		Windows with IG glass 1/4" air sp.	1.69		Windows with 1/2" Low E IG	3.13
Wood solid core 1-3/4 door	3.03		Metal ins. door no glass	15.00		1/2" - 4" air space	1.00

                       

Temperature Formula:  Degrees Fahrenheit - 32 x 0.56 = degrees Celsius

                                    Degrees Celsius x 1.8 + 32 = Degrees Fahrenheit

Liquid:
1 ounce = 29.57 milliliters
1 quart = 0.95 liter
1 gallon = 3.79 liters