Retrofitting Crawl Spaces for Health, Comfort, and Energy Efficiency

RETROFITTING CRAWL SPACES FOR HEALTH, COMFORT, AND ENERGY EFFICIENCY

By: Gavin Healy DISCLAIMER

THE INFORMATION IN THIS DOCUMENT IS BELIEVED TO ACCURATELY DESCRIBE THE TECHNOLOGIES ADDRESSED HEREIN AND ARE MEANT TO CLARIFY AND ILLUSTRATE TYPICAL SITUATIONS, WHICH MUST BE APPROPRIATELY ADAPTED TO INDIVIDUAL CIRCUMSTANCES. THESE MATERIALS WERE PREPARED TO BE USED IN CONJUNCTION WITH A FREE EDUCATIONAL PROGRAM AND ARE NOT INTENDED TO PROVIDE LEGAL ADVICE OR ESTABLISH LEGAL STANDARDS OF REASONABLE BEHAVIOR. NEITHER PACIFIC GAS & ELECTRIC (PG&E) NOR ANY OF ITS EMPLOYEES AND AGENTS: (1) MAKES ANY WRITTEN OR ORAL WARRANTY, EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE; (2) ASSUMES ANY LEGAL LIABILITY OR RESPONSIBILITY FOR THE ACCURACY OR COMPLETENESS OF ANY INFORMATION, APPARATUS, PRODUCT, PROCESS, METHOD, OR POLICY CONTAINED HEREIN; OR (3) REPRESENTS THAT ITS USE WOULD NOT INFRINGE ANY PRIVATELY OWNED RIGHTS, INCLUDING BUT NOT LIMITED TO PATENTS, TRADEMARKS OR COPYRIGHTS. FURTHERMORE, THE INFORMATION, STATEMENTS, REPRESENTATIONS, GRAPHS AND DATA PRESENTED IN THIS REPORT ARE PROVIDED BY PG&E AS A SERVICE TO OUR CUSTOMERS. PG&E DOES NOT ENDORSE PRODUCTS OR MANUFACTURERS. MENTION OF ANY PARTICULAR PRODUCT OR MANUFACTURER IN THIS COURSE MATERIAL SHOULD NOT BE CONSTRUED AS AN IMPLIED ENDORSEMENT. Design

Learn Retrofit

Data Measure THE PERFORMANCE DETAILS

1. Determine if the space is dry enough to seal and insulate 2. Determine air barrier location: crawl space floor or walls and grade? 3. Determine what grade of ground cover you’re going to install. 4. Survey mechanical, electrical and plumbing for opportunities. 5. Determine appropriate insulation for the surfaces considered.

4 DEFINE GOALS FIRST

• PROTECT THE STRUCTURE (LONG-TERM DURABILITY). • REDUCE ENERGY CONSUMPTION: PROVIDE CONDITIONED OR BUFFERED SPACE FOR OPTIMIZATION OF VENTILATION, PLUMBING, & HEATING DISTRIBUTION SYSTEMS. • IMPROVE INDOOR AIR QUALITY: REDUCE PARTICULATE MATTER, POTENTIAL SOIL GASES AND OUTDOOR AIR POLLUTANTS. • DETERMINE WHETHER THE SPACE WILL BE VENTED, UNVENTED, MINIMALLY VENTED, OR MECHANICALLY VENTED. THE GEOMETRY OF CRAWLSPACES

Daylight Shallow Hillside basement & crawl crawl crawl

Basement with crawl to 2 or more sides Full below grade basement

6 TEST TOOLS: DATA LOGGERS

7 What is the RH... AT THE SURFACE?

@ 64°F... RH over 100% @ 70°F... RH = 85%

@ 84°F... RH = 53%

@ 77°F... RH = 68% 65°F Dew Point @ 77°F... RH = 68%

8 When the dew point is higher than the surface temp...

9 Monitoring surface RH - 2nd floor ceiling Surface RH sensor location

Air RH sensor location

10 Air RH vs. Surface RH - Early July - Ft. Lauderdale, FL

Air RH Surface RH

11 MANAGE MOISTURE: ALL CRAWL SPACES ARE WET, SOME ARE MORE WET Bulk Water

Liquid water

Condensation

Liquid water Capillary Liquid water

Evaporation Water vapor MANAGE MOISTURE: BULK LIQUID

SOURCE=PLUMBING LEAKS MANAGE MOISTURE: BULK LIQUID

SOURCE=IRRIGATION MANAGE MOISTURE: BULK LIQUID

SOURCE=GUTTERS MANAGE MOISTURE: BULK LIQUID

SOURCE= INEFFECTIVE CLADDING/WRB USING A SLAB AS A CATCH BASIN

EXPOSED PORCH DECK OVER CRAWL SPACE 19 MANAGE MOISTURE: CAUTION NO WRB AND NO CAPILLARY BREAK MANAGE MOISTURE: BULK LIQUID

SOURCE=GROUND WATER MANAGE MOISTURE: ASSESS THE GRADE AROUND THE BUILDING MANAGE MOISTURE: GRADING TO SLOPE AWAY FROM THE BUILDING MANAGE MOISTURE: TRAPPED GRADING MANAGE MOISTURE: DRAINS TO DAYLIGHT AWAY FROM THE BUILDING

25 MANAGE MOISTURE: BULK LIQUID

PERIMETER FRENCH DRAIN MANAGE MOISTURE: BULK LIQUID

Through the foundation Sidewalks may need to be cut or tunneled under

Gravity drains must daylight at an elevation lower than the lowest portion of the trench in the crawlspace, ideally 10 feet away from the building. 27 INTERIOR GRAVITY DRAIN

28 INTERIOR GRAVITY DRAIN

29 SUMP PUMP FOR FLAT LOTS

30 SUMP PUMP FOR FLAT LOTS

31 MANAGE MOISTURE: CONDENSATION

Temperatures and Dew Points

63 Dinning Temp, °F

58 Dinning DewPt, °F

Master Temp, °F 53 Master DewPt, °F

48 Window Pan Temp, °F

38 3:00 PM 3:00 PM 3:03 PM 3:06 PM 3:09 PM 3:12 PM 3:15 PM 3:18 PM 3:21 PM 3:24 PM 3:27 PM 3:30 PM 3:33 PM 3:36 PM 3:39 PM 3:42 PM 3:45 PM 3:48 PM 3:51 PM 3:54 PM 3:57 PM 4:00 PM 4:03 PM 4:06 PM 4:09 PM 4:12 PM 4:15 PM 4:18 PM 4:21 PM 4:24 PM 4:27 PM 4:30 PM 4:33 SURFACE TEMPERATURE BELOW DEW POINT MANAGE MOISTURE: CAPILLARITY

MOISTURE MOVING THROUGH POROUS BUILDING MATERIALS MANAGE MOISTURE: CAPILLARY BREAK

Capillary break and air barrier gasket

34 MANAGE MOISTURE: HYDROSTATIC

HIGH WATER PRESSURE ON ONE SIDE OF AN ASSEMBLY MANAGE MOISTURE: EVAPORATION

(WATER VAPOR) DRYER TERMINATIONS DEHUMIDIFIER: POOR SOLUTION FOR DRY CLIMATES. PREPARING THE SPACE: REMOVE ALL DEBRIS PREPARING THE SPACE: GRADING AND ROCK REMOVAL/RELOCATION

39 STRUCTURAL REPAIRS BEFORE INSULATION DEFERRED MAINTENANCE CAN LEAD TO FAILURE

41 STRUCTURAL REPAIRS BEFORE INSULATION ESTABLISH WORKING ACCESS ESTABLISH WORKING ACCESS ESTABLISH WORKING ACCESS SOLUTION: GROUND SOURCE VAPOR BARRIER SOLUTION: GROUND SOURCE VAPOR BARRIER SOLUTION: GROUND SOURCE VAPOR BARRIER SOLUTION: GROUND SOURCE VAPOR BARRIER SOLUTION: GROUND SOURCE VAPOR BARRIER SOLUTION: GROUND SOURCE VAPOR BARRIER SOLUTION: SOIL GAS BARRIER SOLUTION: SOIL GAS BARRIER SOLUTION: DIMPLE DRAIN MAT FOR SOIL GASES SOLUTION: DIMPLE DRAIN MAT FOR SOIL GASES

pCi/L 1.2

0.8

0.6

0.4

0.2

0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 101 103 105 107 109 111 113 115 117 119 121 123 125 127 129 131 133 135 137 139 141 143 145 SOLUTION: LIQUID APPLIED VAPOR BARRIER LOCATE AIR BARRIER: LOCATE AIR BARRIER: LOCATE THE AIR BARRIER LOCATE THE AIR BARRIER: INTERIOR PARTITIONS LOCATE THE AIR BARRIER: INTERIOR PARTITIONS LOCATE THE AIR BARRIER: STAIRWELL LOCATE THE AIR BARRIER: STAIRWELL ASSESS THE EXISTING THERMAL BARRIER

 If the existing thermal insulation is air permeable, is it installed in contact with the wood frame surfaces on five sides? Can it be made to be?  Thermal barrier aligned with floor assumes the floor is the air barrier, is the air barrier continuously air tight from rim to rim?  Are there any planned upgrades for the structure; plumbing, electric, and/or mechanical that require the existing thermal barrier be removed?  Is the existing thermal insulation providing habitat for rodents or pests? ASSESS THE EXISTING THERMAL BARRIER

65 ASSESS THE EXISTING THERMAL BARRIER ASSESS THE EXISTING THERMAL BARRIER

67 ASSESSING THE EXISTING THERMAL BARRIER

Four foot on center SOLUTION: FOAM BOARD SOLUTION: THERMAL BARRIER ASSESS THE EXISTING THERMAL BARRIER COMBINATION AIR AND THERMAL BARRIER: SUB-FLOOR CAUTION: DEFINE THE WORK SCOPE LOCATE THERMAL BARRIER: RIM JOIST LOCATE THERMAL BARRIER: ON GRADE LOCATE THERMAL BARRIER: ON GRADE

EPS foam board (ICF) below grade XPS foam board on grade crawl foundation walls. space/basement RIGID FOAM BOARD REQUIRES MORE GRADING, BUT RESULTS IN MORE UNIFORM THERMAL CONTINUITY

77 THERMAL BARRIER ON GRADE: VAPOR BARRIER IN DIRECT CONTACT WITH SLAB

78 LOCATE THERMAL BARRIER: ON GRADE

Apply vapor barrier first, than wall Spray applied foam on top of vapor insulation. barrier.

79 CONSIDERATION: TERMITE REVEAL

TERMITE REVEAL 6”

80 LOCATE THERMAL BARRIER: WOOD FRAME STEM WALL

81 LOCATE THERMAL BARRIER: WOOD FRAME EXTERIOR STEM WALL LOCATE THERMAL BARRIER: WOOD FRAME EXTERIOR STEM WALL CONSIDERATION: WHEN THERMAL BARRIER IS AT PERIMETER WALLS ELIMINATE FOUNDATION VENTS. (MUST HAVE GROUND SOURCE VAPOR BARRIER)

84 CONSIDERATION: NO WATER TIGHT CLADDINGS, OR WEATHER RESISTIVE BARRIER

REMOVE CLADDING TO RIM JOIST, INSTALL WEATHER BARRIER 85 EXTERIOR THERMAL BARRIER

86 EXTERIOR THERMAL BARRIER

87 EXTERIOR WEATHER RESISTIVE BARRIER

88 MASONRY STEM WALL :VAPOR AND AIR BARRIER

89 LOCATE THERMAL BARRIER: MASONRY STEM WALL MASONRY ATTACHMENT

91 MASONRY ATTACHMENT

Powder actuated nails and pressure treated lumber

Vapor barrier button MASONRY ATTACHMENT

93 STONE FOUNDATION

94 MECHANICALLY VENTED CRAWL SPACE

95 HOW MUCH CLEARANCE IS REQUIRED?

96 ASSESS SOURCES OF POOR AIR QUALITY: . RODENTS

A majority of existing California homes that we have inspected show evidence of minor to significant rodent or squirrel contamination.

97 ASSESS SOURCES OF POOR. AIR QUALITY

98 SOLUTION: RAT SLAB

99 SOLUTION: RAT SLAB

100 DRAW THE DIFFICULT DETAILS DRAWN PLANS NEW CONSTRUCTION CRAWL SPACE PLAN 104 SOLUTION: REPLACE FOUNDATION

105 SOLUTION: REPLACE FOUNDATION

106 SOLUTION: TERRACING SLOPED CRAWL

107 Optimizing useable space may be a homeowner’s primary motivation. WHEN BUILDING A NEW CRAWL SPACE PLAN FOR ACCESS ASSESS MECHANICAL, ELECTRIC AND PLUMBING SYSTEMS IN THE CRAWL SPACE

109 ASSESS PLUMBING SYSTEMS IN THE CRAWL SPACE ASSESS PLUMBING SYSTEMS IN THE CRAWL SPACE ASSESS MECHANICAL SYSTEMS IN THE CRAWL SPACE ASSESS MECHANICAL SYSTEMS IN THE CRAWL SPACE ASSESS MECHANICAL SYSTEMS IN THE CRAWL SPACE

114 ASSESS MECHANICAL SYSTEMS IN THE CRAWL SPACE ASSESS MECHANICAL SYSTEMS IN THE CRAWL SPACE

116 ASSESS MECHANICAL SYSTEMS IN THE CRAWL SPACE

117 ASSESS MECHANICAL SYSTEMS IN THE CRAWL SPACE MECHANICAL SYSTEMS: CONDITIONED CRAWL SPACES.

119 ASSESS COMBUSTION VENTS IN THE CRAWL SPACE ASSESS COMBUSTION VENTS IN THE CRAWL SPACE

121 ASSESS COMBUSTION VENTS IN THE CRAWL SPACE

122 ASSESS ELECTRICAL SYSTEMS IN THE CRAWL SPACE

123 ASSESS ELECTRICAL SYSTEMS IN THE CRAWL SPACE ASSESS ELECTRICAL SYSTEMS IN THE CRAWL SPACE TEST TOOLS :

126 TEST TOOLS : DATA LOGGERS

127 SLAB ON GRADE IS NOT THE EASY WAY

 Difficult and expensive to thermally isolate  Still requires vapor barrier and maybe soil gas system  Permanently inaccessible infrastructure low in the house (i.e. Plumbing) SUMMARY

• Wet crawl spaces are incompatible with high performance homes. • Performance improvements on the sixth side pay some of the greatest dividends on building durability, indoor air quality & thermal comfort improvements. • It is ill-advised to proceed with other higher value enclosure improvements prior to addressing moisture balance issues. • The value of accessible utility spaces should not be underestimated. • Space constraints will often dictate what is the most feasible insulation system for an existing building’s sixth side. • It is relatively rare that existing crawl spaces (including many that have received crawl space improvements) meet assumed minimum R-values. www.balancepointhp.com 530-477-0695

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