10/9/2012

1

Performance Issues Related

to Energy Retrofitting

Old Brownstone Buildings

Stanley D. Gatland II

CertainTeed Corporation

7777thththth Annual North American Passive House ConferenceAnnual North American Passive House ConferenceAnnual North American Passive House ConferenceAnnual North American Passive House ConferenceSeptember 27September 27September 27September 27----30, 2012 Denver CO30, 2012 Denver CO30, 2012 Denver CO30, 2012 Denver CO

Session Learning Objectives:

• Identify issues related to energy retrofits of old

masonry buildings

• Understand how to effectively manage air flow

• Understand the impact of energy retrofits on

indoor air quality

• Understand the concept of hygrothermal analysis

through several examples in Chicago, Illinois

7777thththth Annual North American Passive House ConferenceAnnual North American Passive House ConferenceAnnual North American Passive House ConferenceAnnual North American Passive House ConferenceSeptember 27September 27September 27September 27----30, 2012 Denver CO30, 2012 Denver CO30, 2012 Denver CO30, 2012 Denver CO

10/9/2012

2

Climate

Insulation

Air Tightness

Vapor Control

Cladding Design

Cladding

Substrate

Less Risk

Dry

Less

Less

Dynamic

Drain & Vent

Non-Absorptive

Non-Absorptive

More Risk

Wet

More

More

Restrictive

Face Sealed

Absorptive

Absorptive

Moisture Balance Risk Analysis

for Low-Energy Wall Designs

Original concept presented by Mark Williamswith Williams Building Diagnostics, Ltd

Traditional Residential Wall Assembly

• Single or double wythe masonry facades

• Masonry provides building structure

• A lot of air leakage

• Little to no insulation

• Energy retrofits are limited to the inside of the building – exterior façade is the a desired feature

10/9/2012

3

Visible Moisture Damage

• Condensation

and staining

• Mold, mildew and decay

• Freeze-thaw damage

• Corrosion of metals

• Visual appearance, i.e.

buckling of wood siding, efflorescence of brick and mortar, paint failure

Efflorescence of Brick Surface Due

to the Migration of Mortar Salts

Ice Damming due to Air Exfiltration

10/9/2012

4

Managing Air Flow

Three Types of Pressure Differentials

Mechanical Pressure

Wind Pressure

Stack Pressure

10/9/2012

5

Wind Effect

• Wind pressure has a significant effect on buildings and creates a high, positive pressure on the upwind side and a low, negative pressure on the downwind side

• Wind greatly influences the impact of rain on building surfaces

Wind Direction & Speed Vary with Geographic Location and Season

10/9/2012

6

Rain Load Changes with Geographic Location and Building Envelope Orientation

Weather File Analyzer Software Available

• Software is available through the U.S. Department of Energy to evaluate the impact of wind driven precipitation in many localities throughout North America

• For Weather File Analyzer software contact Oak Ridge National Laboratory

www.ornl.gov/sci/roofs+walls

10/9/2012

7

Stack Effect

Stack effect damage of brick façade at top of building

• Stack pressure occurs when atmospheric pressure differences exist between the top and bottom of a building due to temperature differences

• The stack effect causes infiltration at the bottom and exfiltration at the top of buildings during the heating season

• In warm southern climates the stack effect is lessened due to the short heating season

30 Quarts30 Quarts

100X More Moisture by Air Transport than by Diffusion100X More Moisture by Air Transport than by Diffusion

Vapor DiffusionVapor Diffusion

4 x 8 Sheet ofGypsum Board

1/3 Quart1/3 Quart

Air Transport Air Transport

1 in2 Hole

Moisture is Largest Indoor Air Contaminant!

10/9/2012

8

Mechanical Effect

• Mechanical pressure is

caused by HVAC system

pressurization

• Many systems are

designed to create a

slight positive pressure in

the building to reduce the

potential for air infiltration

Ventilation Effect

• Negative pressures due to mechanical and natural

ventilation

10/9/2012

9

Air Barrier Systems

All joints, seams and penetrations

Site-built windows, doors and skylights

Openings between windows and doors

Utility penetrations

Dropped ceilings or chases

Knee walls

Walls and ceilings separating a garage from conditioned spaces

Behind tubs and showers on exterior walls

Common walls between dwelling units

Attic access openings

Rim joist junction

Other sources of infiltration

Specific requirements for fireplaces, fenestrations & recessed lighting

2012 IECC Air Sealing Requirements

10/9/2012

10

Compartmentalize to Control Air Flow

• Isolate connecting spaces to minimize the stack effect impact

• Disconnect building spaces between:

– Foundation and occupied spaces

– Roof and occupied spaces

– Floors– Rooms– Connecting corridors

• Isolate continuous vertical paths between floors

Stairwell

Utility Shaft

Moisture Sources

10/9/2012

11

Construction and Ground Moisture

• Concrete requires large

amounts of water

• Concrete assemblies dry

out over years

• Use vapor barriers under

concrete slabs

• Install proper footing drainage at perimeter

• Direct rainwater run off away from the building

Residential Moisture Generation

0

20

40

60

80

100

120

Soil Wood

Storage

Unvented

Furnace

Gas

Water

Heater

Four

People

Clothes

Drying

Cooking

Cleaning

Bathing House

Plants (5)

• Pints per day

• Pints per 1000 cubic feet

• Pints per load, meal or shower

10/9/2012

12

Dangers of Moisture Storage Claddings

and Air Conditioning

• Inward vapor drive due to solar

exposure is 400x greater with

moisture storage claddings

than non-storage systems

• Air conditioning creates cold

surfaces in building cavities

with temperatures below the

dew point

• Condensation will occur on the

back side of low permeance

vapor retarders, like

polyethylene and FSK facings

Hygrothermal Analysis Examples

10/9/2012

13

• Hygrothermal analysis predicts the impact of transient heat and moisture transfer on building envelopes over time

• Used on planned construction projects and existing buildings with moisture problems

• Specialized software helps the user visualize:– Surface condensation and mold growth potential

– Wetting and drying potential of the building envelope

– Moisture content of building components

• Helps building designers evaluate potential pre-construction moisture risks

• Post-construction, helps analyze and solve moisture problems

• ANSI/ASHRAE Standard 160-2009, “Criteria for Moisture-Control Design Analysis in Buildings

Hygrothermal Analysis of Building Envelopes

Water FilmWater Film

Capillary suction, caused by water

surface tension, draws water into

porous material and tiny cracks

Create capillary breaks to

protect building materials from

absorbing moisture

CavityCavity

Water FilmWater Film

Break Capillary Flow of Moisture

10/9/2012

14

Water vapor will move from areas of high vapor pressure to areas of low vapor pressure through building materials

Water Vapor Diffusion

• Test method for determining the

water vapor permeance of

building materials

• Building codes evaluate materials

using the standard dry cup

method, aka Method A or the

Desiccant Method

• Some exterior building materials

are evaluated using the standard

wet cup method, aka Method B or

the Water Method

ASTM E 96 Water Vapor Diffusion Testing

10/9/2012

15

Water Vapor Permeanceof Common Interior Wall Materials

0.01

0.1

1

10

100

0 10 20 30 40 50 60 70 80 90 100

Mean Relative Humidity (%)

Wate

r V

ap

or

Perm

ean

ce (

perm

)

Plain Gypsum Board

Primed Gypsum Board

Painted Gypsum Board

2 mil Nylon Film

Asphalt Coated Kraft Paper

6 mil Polyethylene Film

Mean Relative Humidity (%)

Wate

r vap

or

Perm

ean

ce

(Perm

s)

0

10

20

30

40

0 20 40 60 80 100

50

60

Glass Mat Gypsum Substrate

Gypsum Sheathing BoardExterior Cement Board

Recycled Paper Board

Oriented Strand Board

15 # Felt

Brick, 5/8”

70

80

Source: Oak Ridge National Laboratory (Wilkes)

Water Vapor Permeance

of Common Exterior Wall Materials

10/9/2012

16

Vapor Retarder Requirements

• Vapor retarder should be placed at the interior

• Avoid low permeance vapor retarders, such as polyethylene film or aluminum foil in:– Climates with high summer

moisture loads– Walls with moisture storage

claddings– Walls with low permeability

exterior sheathings

• IECC requires Class I or II vapor retarder in Climate Zones 4C, 5, 6, 7 and 8

• SVR works in all North American climate zones

Vapor Retarder Categories

PermPerm

Latex Primed and Painted Gyp. Bd. – 1 & 2 Coats (3 - 35)

Latex Primed Gypsum Board - 1 Coat (22 - 66)

Plain Gypsum Board (45 - 85)

6 mil Polyethylene (0.05 - 0.06)

Asphalt Coated Kraft Paper (0.3 - 3)

2 mil polyamide film (0.8 - 36)

11

Vapor Retarder

(Class II)

Vapor Retarder

(Class II)

Vapor Barrier

(Class I )

Vapor Barrier

(Class I )

0.10.10.010.01 1010

Semi-permeable

(Class III)

Semi-permeable

(Class III) PermeablePermeable100100PermPerm

Latex Primed and Painted Gyp. Bd. – 1 & 2 Coats (3 - 35)

Latex Primed Gypsum Board - 1 Coat (22 - 66)

Plain Gypsum Board (45 - 85)

6 mil Polyethylene (0.05 - 0.06)

Asphalt Coated Kraft Paper (0.3 - 3)

2 mil polyamide film (0.8 - 36)

11

Vapor Retarder

(Class II)

Vapor Retarder

(Class II)

Vapor Barrier

(Class I )

Vapor Barrier

(Class I )

0.10.10.010.01 1010

Semi-permeable

(Class III)

Semi-permeable

(Class III) PermeablePermeable100100

Traditionally vapor retarders are defined by building codes as having a standard dry cup water vapor permeance of 1 perm or less

10/9/2012

17

ASHRAE Isothermal Planes Method

==U =U =11

RT

RT

11

11.6111.61= 0.09 Btu/hr ft2 °F= 0.09 Btu/hr ft2 °F

Thermal Resistances R

Outside Air Film 0.17

4” Brick 0.98

4” Concrete Block 0.63

2” Fiber Glass Insulation 8.70

½” Gypsum Board 0.45

Inside Air Film 0.68

Total Resistance (RT) 11.61

Thermal Resistances R

Outside Air Film 0.17

4” Brick 0.98

4” Concrete Block 0.63

2” Fiber Glass Insulation 8.70

½” Gypsum Board 0.45

Inside Air Film 0.68

Total Resistance (RT) 11.61

Outside Air Film4” Brick

4” Concrete

Block

2” Fiber Glass

Insulation

Gypsum

Board

Inside Air

Film

Double Wythe Brick Wall

with Interior Insulation Layer

10/9/2012

18

Marine 4C

Pacific NW

Marine 4C

Pacific NW

Cold & Dry

5B, 6B

Cold & Dry

5B, 6B

Mixed & Humid

3A, 4A

Mixed & Humid

3A, 4A

Hot & Humid 1A, 2A, 3AHot & Humid 1A, 2A, 3A

Cold & Humid

5A, 6A

Cold & Humid

5A, 6A

Extreme

Cold & Humid 7A

Extreme

Cold & Humid 7A

Mixed & Dry

3B, 4B

Mixed & Dry

3B, 4B

Hot & Dry 2B, 3BHot & Dry 2B, 3B

Cold & Dry

5B, 6B

Cold & Dry

5B, 6B

Extreme

Cold & Humid 7A

Extreme

Cold & Humid 7A

Original concept was developed through funding by the US Dept. of Energy’s Building America Program

Continental US Climate Zone Descriptionswith 2012 IECC Climate Zone Designations

Chicago, Illinois – Cold & Humid CZ 5A

High Density Fiberglass Board

Seasonal Wetting & Drying

Interior Brick SurfaceRelative Humidity

FiberglassBoard

Double-Wythe Brick WallChicago, Illinois

10/9/2012

19

Extruded Polystyrene

Seasonal Wetting – Limited Drying

Interior Brick SurfaceRelative Humidity

XPSBoard

Double-Wythe Brick WallChicago, Illinois

Fiberglass Board with SVR

Controlled Seasonal Wetting & Drying

Interior Brick SurfaceRelative Humidity

FiberglassBoard

Double-Wythe Brick WallChicago, Illinois

10/9/2012

20

Simple Cool Roof Analysis

Cool Roofs do the following:

• Reflect more of the sun’s energy back into the atmosphere using high solar reflectance coatings or pigments (SR > 0.70)

• Release more absorbed heat back into the atmosphere using high thermal emittance coatings or pigments (TE > 0.75)

• Keep building’s cooler by reducing roof surface temperature

• Colder surfaces mean a greater potential for surface condensation and moisture accumulation

10/9/2012

21

Cold-Humid ClimateChicago, IL

Roof Surface Comparison

• Black roof surfaces can reach peak temperatures of 190ºF on a hot, sunny summer day

• Highly reflective white surfaces can reduce peak temperatures by as much as 70ºF

White Reflective Roof

Black Roof

10/9/2012

22

Simple Cool Roof AnalysisChicago, IL

• Simple roof without an insulation layer

• White roof–SR = 0.70

–TE = 0.75

• Black roof

–SR = 0.10

–TE = 0.90

Plywood Decking Moisture Content

0

5

10

15

20

25

30

35

10/1/0

0

2/1/

01

6/1/

01

10/1

/01

2/1/

02

6/1/

02

10/1/0

2

2/1/

03

6/1/

03

10/1/0

3

Date (m/d/y)M

ois

ture

Co

nte

nt

(%)

White

Black

Simple Cool Roof AnalysisChicago, IL

• Black roof’s plywood decking moisture content peaks at 20%

• White roof’s plywood decking moisture content peaks at 30%

• Both stable wetting and drying cycles

• Very important to create air tight insulated assemblies with cool roofs

Plywood Decking Moisture Content

0

5

10

15

20

25

30

35

10/1/0

0

2/1/

01

6/1/

01

10/1

/01

2/1/

02

6/1/

02

10/1/0

2

2/1/

03

6/1/

03

10/1/0

3

Date (m/d/y)

Mo

istu

re C

on

ten

t (%

)

White

Black

10/9/2012

23

Good References

• Straube & Schumacher - Interior Insulation Retrofits of Load Bearing Masonry Walls in Cold Climates, Building Science Digest 114, Building Science Corporation, 2007

• Goldberg, Huelman & Gatland II, Universal Building Envelope Hygrothermal Performance Standard for Successful Net-Zero Energy Building Design, Buildings XI Conference, 2010

Question & Answer Session

Thank you for your attention!