Page 31 - Green Builder Remodeling Field Report 2021

6
Why XPS?

A study comparing EPS and XPS
5 rigid insulation found that XPS
Connor Study retains its R-Value longer, over a
XPS Data wide variety of moisture and heat
condtions. SOURCE: DUPONT
R-Value per inch of Thickness, °F ft 2 h/Btu
4

3

Connor Study
EPS Data
2

EPS Log Avg
1 EPS-One STDEV
XPS Log Avg
XPS-One STDEV
EPS Data
XPS Data
0
5 10 15 20 25 30 35
Years in Service

the foam and the wood sheathing it is slow to dry and can lead
to fungal decay. To address this concern, we will apply Tyvek 6 R-Values
DrainWrap over the OSB sheathing to protect the OSB and
provide drainage to move water out of the system.
5
Traditional three coat cementitious stucco adds a lot of
weight and thermal mass. To address that problem we instead
applied a thin coat stucco system which goes on thinner, 4
resulting in less thermal mass and heat transfer.
The Thermax foam board and the LathNet (from Mortar Net)
rain screen stucco reinforcement help decouple the mass of R-Value Per Inch 3
the stucco from the wall system, and will also provide water
drainage. The LathNet has a ¼” thick polyester rainscreen 2
material, which separates the lath and stucco from the foam.

DEALING WITH BEAMS 1
Because the remodeled home has large window and door
openings, it required some large steel and wood beams to sup-
port the building loads. Wood has an R-value of about 1.25 0
per inch, so a 5.6-inch thick beam would have an R-value of Thermax TM Fiberglass Wood Gypsum Steel
7. Adding the Thermax exterior insulation pushed the wood

REMODELING FIELD REPORT GREEN BUILDER 31