Moisture Management with Rainscreen Strategy - Cosella-Dörken Products, Inc.

Ventilated Rainscreens for
Improved Moisture Management

DELTA® Systems
State of the Art
Construction Products

Commercial

Residential


Extensive Experience

Involvement in construction
products since 1892

Market leadership in Europe
with multiple product lines


THINK GLOBALLY -
Act co-operatively
Germany
France
Serving the Belgium
international market Netherlands
offers excellent Luxembourg
opportunities of Switzerland
qualitative and U.S.A.
quantitative growth.
Italy
Hungary
Poland
Czechia
Slovakia
Canada
Mexico


As we belong to the chemical
industry, we feel particularly
committed to preserving and
protecting the environment.

Committed to environmental protection


improved Moisture Management

December 2009


Cosella-Dörken is a Registered Provider with The American Institute of
Architects Continuing Education System. Credits earned on completion of this
program will be reported to CES Records for AIA Members. Certificates of
Completion for non-AIA members are available upon request.

This program is registered with the AIA/CES for continuing professional
education. As such, it does not include content that may be deemed or construed to
be an approval or endorsement by the AIA of any materials of construction or any
method or manner of handling, using, distributing, or dealing in any material or
product. Questions related to specific materials, methods, and services will be
addressed at the conclusion of this presentation.


“Ideal World”
Bulk water does never intrude
behind the water-resistive barrier (WRB)

“Real World”
Bulk water intrudes behind the
water-resistive barrier through
• penetrations
• flashing details
• other imperfections


Why Worry About Moisture?


Durable, Sustainable Designs … Incorporate Drying ….


Wall Wetting Mechanisms are Complex
1. Rain
• Absorption (wicking)
• Penetration
• Splash and drips 3.

2. Water Vapor 2. 1.
• Diffusion
• Convection (air leaks)
3.
3. Built-in Moisture
• Vapor
• Liquid / frozen

4.
4. Ground Moisture
• Capillary
• Diffusion
• Liquid penetration


Moisture in Enclosure Walls
can originate from inside of buildings

• Transpiration from human body
• Evaporation from plants
• Pets
• Cleaning of dwellings
• Personal hygiene
• Laundering, drying
• Cooking, heating water
• Humidification
• Broken water pipes, backed up drainage
• Seasonal absorption
• New construction moisture


Combination of Moisture & Temperature
causes mold spores to germinate

Days to
Growth Rate
Germinate

– 30-day average surface RH > 80%
or
– 7-day average surface RH > 98%
or
– 24 hours at RH 100%
and
– surface temperature
© ORNL
between 50°F and 104°F
© ASHRAE SPC160P


Long ago …
buildings were less sensitive to moisture
• Integral vapor resistance
• Massive moisture storage capacity

Masonry

Plaster


Not too long ago …
Framed buildings had drying capacity

• Little vapor resistance
• Little moisture storage capacity
• Little insulation and air leakage: Caused walls to dry!


More Recently ...
Improved energy efficiency => Enclosures retain moisture

• Began to add insulation & comfort
• Moisture problems in cold climates noted in 1930’s
• Paint peeling of siding


Linkage
moisture flow, heat flow & air flow

Functions of building enclosure:
1. Separate inside and outside of building
2. Protect inside from external elements
3. Conserve energy

Enclosure performance:
• heat flow
• air flow
• & moisture flow are interlinked

Resulting in:
• elevated relative humidity
• condensation
• reduced service life


Water can occur in 3 phases

Building enclosures need to safely manage water, regardless of its phase


Water polarity effects rate of Absorption and Desorption

Water Molecule:
• One large negatively charged oxygen atom
•Two smaller positively charged hydrogen
atoms

Polarity:
• Water molecules glob …. stick to each
other due to atom polarity
• Opposite polarities attract
• Like polarities repel, i.e. magnet
• Adsorptive moisture occurs when
water’s hydrogen atoms bond to
oxygen atoms on hard surfaces.


How Does Water Move?
1) Water moves because of Gravity

• Redirect water
• Shingle to outside


2) Water moves because of Capillary Wicking

Cohesion and Adhesion
The smaller the fissure / crack,
the greater the suction and rise of water


3) Water moves because of Pressure Differentials
(i.e. wind pressure)
- Infiltration
- Exfiltration


How Does Vapor Move?

1) Vapor moves because of Air Flow
(higher to lower air pressure)

- cracks Wind Effect

- gaps
- penetrations

Higher pressure to
lower pressure

Stack Effect

Combustion & Ventilation


How Does Vapor Move?

2) Vapor moves because of Diffusion
higher to lower vapor pressure

3) Vapor moves because of Heat flow
warm to cold

Bi-Directional flow
• Outside to Inside
• Inside to Outside


Water Vapor in Air

• Water vapor exists in all air
• Air has maximum water vapor holding capacity
• This capacity changes dramatically with temperature
• When the maximum holding capacity is exceeded,
condensation occurs
• Water vapor resides in air or building materials
(Relative Humidity)


Water Vapor Pressure

Example: Water Vapor in a Container

Raise Containment Temperature =
• More energy (kinetic energy)
• Higher velocity of water molecules
• Harder collisions with wall

Increase Number of Molecules =
• More collisions with wall (higher pressure)
• Pressure another measure for moisture
content


Air Moisture Content vs. Temperature

Vapor Pressure (Pa)
Temperature
© Buildingscience Consulting


How does
Condensation occur?

1) Adding Moisture


How does
Condensation occur?

2) Reduce Temperature


Temperature Differential can cause Condensation

Drop in temperature along the wall


Condensation caused by Temperature Differential


Pressure Differential causes Air Leakage
pout < pin

Air moves into/through enclosure walls and “drags” moisture with it


Air Leakage and Pressure Differentials can lead to

Condensation

Air leakage moves moist
air (vapor) through the
wall assembly to locations
where it could condense


Penetrations need an Air Barrier


Air Leakage Examples
• Gaps between sheathing boards
• Penetrations


Air Leakage Examples

• Floor drains
• Joints & cracks
• Rim joists, sill plates
• Windows
• Receptacles, switches
• Ceiling light fixtures
• Attic hatch
• Chimney penetrations
• Plumbing stacks
• etc.


Why Does Vapor Diffusion Occur?

Vapor diffusion is driven by
Vapor Pressure Differentials

If moisture content in air is different inside
and outside of a wall, vapor diffusion will
occur until the vapor pressure differential is
eliminated (equal vapor pressure on either
side of the wall)

Resistance to vapor diffusion depends on
water vapor permeance of materials
(perm rating)


Solar Driven Moisture

After a rain-period absorptive
cladding is soaked with water

Solar Energy can
• evaporate moisture
• push vapor inwards!

Vapor may condense inside
the wall cavity!


Solar Driven Moisture
External Wall Temperatures can be warmer than
interior room temperatures
Vapor pressure in cement cladding:
Vapor pressure in cement cladding:
Example: > 16,000 Pa
> 16,000 Pa
Sunny Day in February,
Interior vapor pressure: 1,300 Pa
Interior vapor pressure: 1,300 Pa
Puyallup, WA
Outdoor Temperature: 32 F
Structural Sheathing: 158 F
Temperature measured behind
dark painted cement cladding on
south facing wall
Indoor Temperature:
68 F to 70 F at 50% RH



Water and Vapor get in


What we want ...
• Leak-free buildings
• High R-values
• Airtight, energy efficient walls

The problem:
• Walls still get wet
• Today’s building enclosures have lower moisture storage capacity
and lower drying potential than in old times

Resulting in:
• Moisture accumulation
• Decay


Wall Drying Mechanisms
1.
1.

1. Surface Evaporation
4.
2. Diffusion / Convection
2.
3. Drainage
4. Air Exchange (Ventilation)

3.

1.


Drainage and the Building Code

International Residential Code (IRC):
Section R703.1 was modified in 2006 to require
"a means of draining water that enters the assembly
to the exterior"

The code does not define what constitutes Drainage


Three Cladding Application Methods

1. Direct 2. Vented 3. Ventilated


Remove Threat of Water Suspension
and Vapor Drive

• Capillary break
• Incorporate Effective drainage
• Ventilation behind the cladding system
• Drying energy to remove moisture from the sheathing material

Solution:
Ventilated Rainscreen


Ventilated Rainscreen with 3-D Structure

• Drainage space on both sides of membrane
• Capillary inactive and durable barrier to liquid water
• Vapor impermeable – eliminates solar driven moisture
• Dual ventilated air cavity enables drying of wall
assembly (passive solar energy)
• Tested for Thermal Cycling


Heat, Air & Moisture Flow in dual ventilated cavity

Outer chamber
• deflects and drains bulk
water
• ventilates heat and vapor
Inner chamber
• drains condensate moisture
and possible bulk water
• enables ventilation to dry
sheathing board


Air & Heat Flow speeds Material Drying
Effective combination of drying mechanisms
Comparison of different Drying Techniques on Paper Towel Wetting
Mass of Water (g)

9 x faster

Time (min)
None Fan Heat Heat & Fan
© Dr. J. Straube; Westford Symposium ‘06


Difference between Absorption & Adsorption

Absorption:
Is the capillary
movement of moisture
in hygroscopic/porous
materials, i.e. suction
in capillaries.

Adsorption:
Is the bonding affect
of oxygen atoms on
solid surfaces
attracting hydrogen
atoms of moisture.
This is called
hydrogen bonding.


Wind Drying
3-D Membrane
Weight of Water (g)

# 15 Felt

Time (hours)

Weight of Water (g)
Drying Rate of Wall with 3-D Membrane and Wind

Time (days)

Drying Rate of Wall with Wind


Total Moisture in Wall – Atlanta
Hygrothermal modeling with Moisture-Expert®

Safety

#15 Felt
3-D Membrane

Moisture Management
with Rainscreen Strategy

Denver: Cold
Build America Climate Regions

Cold
A cold climate is generally defined as a
region with approximately 5,400 heating
degree days (65°F basis) or more and fewer
than approximately 9,000 heating degree
days (65°F basis).


Denver Climate Data

Yrs Data Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Normal Precipitation 30 0.51 0.49 1.28 1.93 2.32 1.56 2.16 1.82 1.14 0.99 0.98 0.63 15.81

Lowest Temp. 61 -25 -30 -11 -2 22 30 43 41 17 3 -8 -25 -30

Highest Temp. 61 73 76 84 90 96 104 104 101 97 89 79 75 104

Normal Daily Max Temp. 30 43.2 47.2 53.7 60.9 70.5 82.1 88 86 77.4 66 51.5 44.1 64.2

Normal Daily Min. Temp. 30 15.2 19.1 25.4 34.2 43.8 53 58.7 57.4 47.3 35.9 23.5 16.4 35.8

Normal Daily Mean. T. 30 29.2 33.2 39.6 47.6 57.2 67.6 73.4 71.7 62.4 51 37.5 30.3 50.1

Avg. Wind Data 47 8.6 8.7 9.6 10 9.3 8.8 8.3 8 7.9 7.8 8.2 8.4 8.6

Cooling Degree Days 30 0 0 0 2 23 135 261 217 57 0 0 0 695

Heating Degree Days 30 1 9 136 436 826 1078 1111 892 788 524 267 60 6128

Avg. Solar Index 46 71 69 69 67 64 70 71 71 74 72 64 67 69

Avg. Relative Humidity Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average
M = morning M A M A M A M A M A M A M A M A M A M A M A M A M A
A = Afternoon 35 63 49 67 44 67 40 67 35 70 38 69 35 68 34 69 35 68 34 65 36 68 49 65 52 67 40

mph Gust

Max Wind Speed, mph 30 43 45 45 45 56 41 46 55 49 49 41 38 56 46 83


Denver Climate Data

• High Solar Index
• Moderate AM R/H
• Low PM R/H
• Cold Temps from Oct.
to April
• Low precipitation

Excellent Drying
Potential


Design for Denver, CO Cold Climate Conditions

Eliminate climate/cladding moisture from entering enclosure:
• capillary break cladding from enclosure
• enable drainage
• engage drying

Control formation of Dewpoint in walls:
• manage thermal temperature drop
• reduce thermal breaks
• enable drying to sustain enclosure system if during 50 year term wall
diaphragm movement opens conduit paths develop through
insulation, vapor and air barriers.


s
ng
di
ad
Cl
/
gy
er
En
lar
So
H
R/
p/
em
Flow In

rT
rio
te
Ex
June – Sept.

Int. Temp. R/H

Flow Out
Oct. - May

Wall A Wall B

3-D Dual Chamber Ventilated
Rainscreen Siding

Delta Dry Ventilated Rainscreen
Wall A: Most USA
EPS/XPS Foam
Direct application to wall
• ventilates heat, vapor, WRB “Drainage” Membrane
• drains bulk water,
Sheathing
• optimizes enclosure drying by
Insulation
keeping the WRB Dry.
Interior Gyp Board installed in
“Air Barrier”, sealed to walls
Wall B: Cold Climate / Energy and ceiling.
Efficient.
Ventilated rainscreen application Permeable gypsum sealer

with exterior insulation Permeable latex paint
• improves total insulation wall
value,
• incorporates a thermal break,
• moves dewpoint outboard Drawing expanded for clarity.
assembly during cooler months,
It is the responsibility of the
• ventilates heat, vapor,
architect/designer to calculate
• drains bulk water, % to total insulation
• protects the insulation board. requirement for climate
temperature and R/H moving
dewpoint from interior of
enclosure wall to outboard
structural sheathing.

Ventilated Rainscreen Enclosure Wall Assembly

Siding

• ventilates heat, High Perm WRB Membrane

Sheathing
• ventilates cladding vapor, Insulation

Smart vapor retarder
• drains bulk water, and air barrier

• optimizes enclosure drying by keeping the “Air Barrier”, sealed to walls
and ceiling.
WRB Dry.
Permeable gypsum sealer

• Dual Chamber separates climate and cladding Permeable latex paint
conditions from enclosure wall conditions.

Drawing expanded for clarity.

It is the responsibility of the
architect/designer to calculate
% to total insulation
requirement for climate

Energy Efficient, Ventilated Rainscreen Sustainable Enclosure Wall.

Cold Climate: Siding

Move dewpoint from inside building
enclosure to outboard enclosure. XPS Closed Cell Foam
Reduce enclosure wall thermal breaks.
WRB “Drainage” Membrane
Provide capillary break from cladding to
Sheathing
exterior insulation and wall.
Insulation
Drain and ventilated cladding system.
“Air Barrier”, sealed to walls
Dewpoint Example: and ceiling.

Permeable gypsum sealer
Exterior Temp. 15F
Interior Temp. 70F Permeable latex paint
Interior R/H. 40%
Dewpoint F. 44F

Move Dewpoint Outbound of Inner Face
of Sheathing: Drawing expanded for clarity.
% to total insulation outbound sheathing
to be 55% total wall Insulation R- It is the responsibility of the
Value. architect/designer to calculate
R value of cavity = 8.587 % to total insulation
Total R Value of wall = 22.5 requirement for climate


Purpose of Rainscreen in Cold Climate:

1.Provide capillary break between cladding to enclosure wall, specifically capillary break
between cladding system and thermal insulation located outboard structural enclosure
sheathing. Eliminate snow melt from moving into enclosure wall and exterior insulation.

2.Two chamber rainscreen with full capillary break protects exterior insulation and seam
tape long term, i.e. sustainability through seasonal climate changes. Wetting to
insulation is reduced and incidental wetting is quickly dried.

3.Provides drainage and drying to cladding. Reservoir claddings such as natural stone
and masonry veneer can drain and dry at both interior and exterior surfaces, reducing
and perhaps eliminating efflorescence.

Bend, OR Trip, 2/07/08

Copper Flange
hides presence of
3-D Rainscreen.

Drainage and
ventilation played a
significant role in the
architects cold climate
design to manage bulk
water drainage and
vapor flow at the
exterior of the
enclosure.


More pictures of
ventilation path to
sheathing chamber
under copper flashing.


Copper flashing
covering mortar,
3-D Rainscreen
and drainage
wall kick-out
flashing.


3-D Rainscreen is
ventilated via the 1”
continuous gap
through soffit.


Ventilated Rainscreens
Improve Enclosure Wall Design

• Incorporate drainage spaces to rid the wall assembly of bulk water

• Incorporate air spaces to provide ventilation for enhanced drying
potential of wall assembly

• Separate air-gaps with an impermeable plane: Capillary break

• Eliminate solar driven moisture from absorptive claddings


Field Performance Testing
ORNL Natural Exposure Test Facility, Charleston, SC


Test Wall Setup
Sensors: Moisture Content, RH, Temperature, Heatflux


Instrumentation of Test Walls Assembly

R/H Sensors:
RH1 is attached to the inner
most part of Stucco
RH2 is attached to the
exterior of Delta Dry
RH3 is bored into the exterior
sheathing board (placed in the
middle of stud cavity).
RH4 is attached to the interior
top middle of stud cavity).
RH5 is attached to the interior
bottom middle of stud cavity).
RH6 is attahced to the
exterior sheathing board.

Charleston was both hot and humid.


Extreme Humidity:
Mildew & Moss growing
on vinyl test wall


7:00 am condensation forming on Delta Dry, prior to stucco application.
Condensation evaporated in approximately 20 minutes.


Field Verification with Different Claddings
Sensor RH 3
OSB (out)
100
RH or T % (Exterior Sheathing)-

90
80
70
Stucco SBPO
60 Brick SBPO
Nov

50 Brick Delta-Dry
3-D RS
3-D

RHout
40 Tout
30
20
10
0
1
31
61
91
121
151
181
211
241
271
301
331
361
391
421
451
481
511
541
571
601
631
661
691
Time (hr) 721


Field Verification with Different Claddings
Sensor RH 3
OSB (out)
100
RH or T % (Exterior Sheathing)-

90
80
70
Stucco SBPO
60 Brick SBPO
Nov

50 DELTA-DRY
3-D Memb.
Brick Delta-Dry
RHout
40 Tout

30
20
10
0
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
Time (hr)

Moisture Management

Hourly Heat Fluxes - Winter - Summer
1-year field test, ORNL NET Facility in Charleston, SC


Adhered Manufactured Veneer
Highly absorptive cladding
Moisture sensitive
substrate
Elevated RH and MC

Vapor permeable
WRB

Condensation in
summer

Highly absorptive
cladding


Issues and Problems
with highly absorptive claddings

1) Poor Drainage (Leaks)
• Solution: small gaps or drainage layer
• ‘Creped’ WRB, two layers of building paper

2) Inward Vapor Drive
• Stucco & Adhered Veneers = very high moisture storage
• Wet cladding + undrained & absorptive water + solar heating = rising
vapor pressure
Direction of Vapor Drive is inward!



Grooved Dimple Sheet:
Ventilated, vapor impermeable Rainscreen mat


Field performance testing at testhut in Waterloo, ON
Dr. John Straube, Building Science Corporation


Framing Moisture Content
Framing Moisture Content (%)

unsafe
Summer time inward vapor drives

safe
DELTA-DRY WALL

STANDARD WALL


Relative Humidity in Cavity space (mid)
RH > 80% for more than 5 months

unsafe
Relative Humidity (%)

safe
DELTA-DRY WALL

STANDARD WALL


How to Ventilate - Open Top and Bottom


Questions ?

This concludes the
American Institute of Architects
Continuing Education Program


Natural Climate Testing

CLADDING SYSTEM Performance Testing:
Stucco
Brick
Masonry Veneer – Interior Water Leak.
Masonry Veneer – 85% Ventilation Closure.

DETAILS:

THERMAL AGING
Differential Scanning Calorimetry

Factors Influencing Drying


www.deltadry.com


Evaluation of Stucco Cladding Assembly
3 Coat
South-East Stucco
Assembly
9 11 12 13

Ventilated
Wall Sheathing WRB Rainscreen WRB Wire Lath Stucco
SBPO SuperJumbo 3 coat
# 9 OSB White Delta Dry Tex 60 Wire Lath stucco North West
# 11 OSB
SBPO
White
No
Rainscreen
SuperJumbo
Tex 60 Wire Lath
3 coat
stucco
16
SuperJumbo SuperJumbo 3 coat
# 12 OSB Tex 60 Delta Dry Tex 60 Wire Lath stucco
SuperJumbo 3 coat
# 13 OSB No WRB Delta Dry Tex 60 Wire Lath stucco
SuperJumbo 3 coat

Moisture Management


February

40 - 50% R/H Interior Vapor Pressure

68 - 72% R/H Exterior Vapor Pressure



February 2008 3 Coat Stucco – R/H All Walls

80 RH-3

75

70

65

60 Wall11-RH3
Wall13-RH3
R/H 55 Wall9-RH3
Wall12-RH3
50
Wall16-RH3
45

40

35

30
1 31 61 91 121 151 181 211 241 271 301 331 361
Time
# 9 OSB White Delta Dry Tex 60 Wire Lath stucco
SBPO No SuperJumbo 3 coat
# 11 OSB White Rainscreen Tex 60 Wire Lath stucco
SuperJumbo 3 coat
SuperJumbo 3 coat
# 16 OSB No WRB Delta Dry Tex 60 Wire Lath stucco North Facing Wall: Non Solar Exposure


February 2008 3 Coat Stucco – Walls 11 & 13

RH-3

R/H

Time

Ventilated
Wall Sheathing WRB Rainscreen WRB Wire Lath Stucco
SuperJumbo 3 coat

Moisture Management


April

64 - 74% R/H Exterior Vapor Pressure

48 - 52% R/H Interior Vapor Pressure



April 2008 3 Coat Stucco - All Walls
90

80 RH-3

70
WALL11-RH3
WALL13-RH3
R/H 60 WALL9-RH3
WALL12-RH3
WALL16-RH3
50

40

30
1 22 43 64 85 106 127 148 169 190 211 232 253 274 295 316 337 358
Time
SuperJumbo 3 coat
SuperJumbo 3 coat
North Facing Wall: Non Solar Exposure

Moisture Management


June

76-80% R/H` Exterior Vapor Pressure

38 to 42% R/H
``
Interior Vapor Pressure

77 °F


June 2008 3 Coat Stucco - All Walls

RH-3

R/H

Time
SuperJumbo 3 coat
SuperJumbo 3 coat
# 16 OSB No WRB Delta Dry Tex 60 Wire Lath stucco North Facing Wall: Non Solar Exposure


Stucco Walls Slide Summary
Months: February, April & June
Walls with least dwell time from R/H accumulation: Delta Dry

Lowest Avg. R/H Wall Assembly (no walls failed due to high M/C or R/H)

Feb. *1) Delta Dry
2) Delta Dry & SBPO
3) SBPO & no rainscreen Greater resistance to outbound moisture
flow resulted in higher moisture dwell time
3) Delta Dry & 60 minute building paper in sheathing compared to case 1 & 2.
April *1) Delta Dry & 60 minute building paper WRB Paper added buffer to inward
moisture vapor flow.
2) Delta Dry
3) Delta Dry & SBPO Warmer temperatures … increased moisture vapor
uptake in evening resulted in higher R/H in sheathing
4) SBPO & no rainscreen than with building paper and ventilated rainscreen.
June *1) Delta Dry
Paper added buffer to inward
2) Delta Dry & 60 minute building paper
moisture flow.
3) Delta Dry & SBPO Warmer temperatures … increased moisture vapor
uptake in evening resulted in higher R/H in sheathing Back
3) SBPO & no rainscreen than with building paper and ventilated rainscreen.
End

*1) Lowest R/H wall assembly


Evaluation of Brick Cladding Assembly

Instrumentation of
Test Walls.

17 thermal sensors
5 R/H sensors
8 M/C sensors
1 H/F, heat flux
sensor


Charleston Natural Exposure Test Facility:
R/H in Wall
Sheathing - Delta Dry - Brick

Charleston Natural Exposure Test Facility: Moisture Content in Wall
Brick Cladding

Result: Low moisture content in wall.

Moisture Management

DELTA®-DRY optimizes 4.

Wall Drainage & Drying Performance
1. 1.

1. Surface Evaporation
2.

2. Diffusion / Convection
2.
3. Drainage
4. Ventilation
3.

3.

1.

Back
End


Masonry Veneer Test Panel Wall Construction

Walls design to be perfect w/ no expectation of
water penetration.

Each wall panel is sealed to be isolated from
heat and moisture affects of testing facility.


Masonry Veneer Bottom
Edge Detail

Starter piece of wood used as straight edge to
help support stone veneer until mortar is set
(standard practice).


Sensors

Moisture Content Wafer

Moisture Content Pins

Relative Humidity Sensor w/ Temperature Sensor


Wall Leak: Potential:
Wall Drying
AtAt the end of 1 year testing,
the end of 1 year testing,
intentional wall wetting at the wall
intentional wall wetting at the wall
interior was conducted.
interior was conducted.
“A“A total of 12 oz. was injected over
total of 12 oz. was injected
overperiod of fourfour days to
a a period of days to simulate a
small but steady leak from, for
simulate a small but steady leak
example, a window.”
from, for example, a window.”


Sensor Locations in
Enclosure Assembly


Onset of
Wall 9: Building Kraft Paper and Masonry Veneer, Standard Wall
interior wall
Wall 10: Delta-Dry, Ventilated Rainscreen Wall wetting.
16% M/C correlates to a surrounding R/H of 80%


Onset of
Wall 7: Delta Dry interior wall
wetting.
Wall 8: Standard Wall


Ventilation Closure Testing:
85% of Bottom & Top Venting Sealed.


85% Delta Dry Ventilation Closed

Wall R/H with ventilation 85% closed Onset of
Delta Dry South & North
slightly higher to previous year and time Ventilation
Walls
frame with ventilation 100% open. Closure.



Wall M/C with ventilation 85% closed Onset of
Delta Dry South Wall Ventilation
remained parallel to previous year and time



Back
End

Wall M/C with ventilation 85% closed Onset of
Delta Dry North Walls Ventilation
remained parallel to previous year and time


Intentional
Wall Wetting:

North Face Walls:
• Delta Dry dries from 33% M/C to 22% within 2 weeks.
• Standard Wall dries from 33% M/C to approximately 26% M/C in 4 weeks.

South Face Walls:
• Delta Dry dries from 25% M/C to 13% M/C within 1.5 weeks and continues to 9% M/C Back
within 4 weeks.
End
• Standard wall dries from 25% M/D to 20% in 1.5 weeks and fluctuates +/- 2% during the
remainder of the month.


Differential Scanning Calorimetry

DSC used with polymers
serves to determine
thermal effects and
materials data:
• Melting - crystallization
• Glass transitions
• Thermo-stability
• Onset of Oxidation
Energy

Chart 1: Oxidation
Induction Time
In a nitrogen chamber add
energy to raise polymers
slightly above melt point.
Flush out nitrogen and add Chart 1

oxygen. If polymers oxidize
they react to oxygen with an
exothermic reaction …. they
release energy. Back
Oxidation Resistance of DELTA®-DRY is at least 60 times
End
higher than mesh monofilament products.


Application Details Available

Back
End

www.deltadry.com

Molds can germinate and grow
quickly in the presence of high R/H.

Days to
Growth Rate
Germinate

ORNL

Wetting and Drying characteristics
of porous materials
Sorption/Suction Isotherm (Baumberger Stone)

ORNL

Capillary Tube Size affects absorption,
Tube Size and Adsorption affects Desorption

ORNL

Dwell Time in porous materials for Bound Water is greater
Free Water is held
than Free Water
in cell cavities.

Bound water is
held within cell
walls by hydrogen
bonding to the
cellulose of the
wood walls.

More specific:
water binds to
-hydroxyl groups
-Hemicellulose
-Lignin molecules

WRB’s
act as a barrier
to air flow ……
Increasing
drying time
and dwell time
of moisture in
materials we
wish to dry.

WR
B

Back
End


Heat & Moisture Transport Characteristics of Wood Frame
Wall Systems with 3 Cladding Application Methods tested
in Pacific Northwest Marine Climate

2003 - 2004
2005 - 2006
Washington State
University
Oak Ridge National
Laboratory

Test Hut Facility

Direct Cladding Application:
Annual Rainfall 25” Annual Rainfall 36”
Year ‘03-’04 Year ‘05-’06

Wall Assembly:
• Latex Paint
• ½” Drywall
• Poly
• R-21
• OSB
• 1 x 60 min.
• 7/8” Cement Stucco

safe unsafe
R/H
safe unsafe

Interior Temp. 68 to 69.8 F.
Interior R/H 50 to 55%

Vented Cladding Application:
Annual Rainfall 25” Annual Rainfall 36”
Year ‘03-’04 Year ‘05-’06

Wall Assembly:
• Latex Paint
• ½” Drywall
• Poly
• R-21
• OSB
• 1 x 60 min.

safe unsafe
safe unsafe
R/H


Ventilated Cladding
Application: Annual Rainfall 25” Annual Rainfall 36”
Year ‘03-’04 Year ‘05-’06

Wall Assembly:
• Latex Paint
• ½” Drywall
• Poly
• R-21
• OSB
• 1 x 60 min.
• ¾” Ventilated

safe unsafe
safe unsafe
R/H



Portland Climate Data

Exterior Temperature
Enclosure Wall
Diffusion Dewpoint

Interior Temp. 70 F.

D/P Interior @50% R/H


Department of Energy Zebra Project


Zebra Project
Outdoor Air Temperature: North Facing Roof Assembly
Month Air Temp. change ranges from 8F Metal Roof: DELTA®-Trela
Heat Flux
to 60 F, represented by blue line.
Up spike in temp. occurs during day
hours.
Down spike in temp. represents night.

Outdoor Air R/H:
R/H represented by pink line.
A down-spike in R/H represents
drying during day by solar radiation.
An up-spike in R/H represents elevated
humidity in air due to absence of solar
energy - night.

Summary: Day from night provides
solar energy with temp. swings ranging
from 15 to 35 degrees.
Heat flux in underside of OSB deck
varies 2 to 3 degrees daily, and 5
degrees for month, ranging from 65F to
70F.
Deck temp. variance compared to
outdoor air temp. variance demonstrates
Trela air space evacuates heat.


Zebra Project
South Facing Roof Assembly
Metal Roof: DELTA®-Trela
Outdoor Air Temperature: Heat Flux

Month Air Temp. change ranges from
8F to 60F, represented by blue line.
Up spike in temp. occurs during day
hours.
A down spike in temp. represents night.

Outdoor Air R/H:
R/H represented by pink line.
A down-spike in R/H represents
drying during day due to solar radiation.
An up-spike in R/H represents elevated
humidity in air due to absence of solar
energy - night.

Summary: Day from night provides
solar energy with temp. swings ranging
from 15 to 35 degrees.
Heat flux in underside of OSB deck
varies approx. 2 to 3 daily and 6
degrees through month, 64F to 70F.
Deck temp. variance compared to
outdoor air temp. demonstrates Trela
air space evacuates heat.


Dörken is parent company to Cosella-Dörken and located in Herdecke Germany.

Moisture Management with Rainscreen Strategy - Cosella-Dörken Products, Inc.

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