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International Wallcovering Manufacturers Association

Mold and Mildew Presentation

Gerald M. RussoRoman Decorating Products

15 October, 2004

Mold and Mildew- How bad can it be?

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Interior and back wall-away from the window

© Wallcoverings Association, 2004

What Mold Needs to GrowWhat Mold Needs to Grow

??Source of moldSource of moldsporesspores

??A nutrient sourceA nutrient source

??AppropriateAppropriatetemperaturetemperature

??MoistureMoisture

Mildew Square*

Spores

Food

Mo

istu

re

Warmth

* Mold and Mildew in Hotel and MotelGuestrooms in Hot and Humid Climates,The Hospitality Lodging & Travel ResearchFoundation, 1991

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Mold and Mildew

?Mold spores are everywhere?Mold grows at the same temperature we live?Building materials act as a food source?Mold must have water to live

How does moisture enter a room?

?Roof, window, and exterior wall leaks?Leaking pipes and plumbing?Negatively pressured building?Open doors and windows?Leaks around doors and windows?Leaks through the wall openings - plumbing

and electrical?Through open doors and windows

How is moisture generated in a room?

?People - perspiration and breathing?Cooking - water and ventless gas appliances?Pipes leaking or condensing? Improperly functioning or inappropriate

sized HVAC system

Two Types of Room Interior Moisture? Open doors and

windows- Condenses onto metal,

bed clothing, walls, and furniture

- Solution: constantly running HVAC should eliminate and control

? Infiltrating air-through the wall- Condenses onto cool

surfaces in the wall cavity, such as: metal stud, nails, screws, etc.

- Solution: control negative pressure and temperature

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What usually happens?

?Vinyl wallcovering is impermeable and acts as a vapor barrier on the wall

? If the wall cavity is dry then there is usually no danger of mold starting to grow

? If moisture gets into the wall cavity, it must be eliminated, or mold will grow

How to control moisture?

?Proper design of the building?Proper construction techniques?Positively pressured building?Appropriate wallcovering selection

Will breathable/perforated wallcovering eliminate mold?

? If moisture is extensive, mold will always be a problem, even with paint finishes

?Steps must be taken to eliminate moisture flowing into a building

?Permeable wallcoverings will reduce the potential for growth of mold and mildew

How is wallcovering breathability regulated today?? In the US, HUD has the only recognized

standard and it is for modular housing?The standard is 5 perms for the wallboard,

primer, adhesive and the wallcovering?Test method specified is the E-96?E-96 has several versions - wet and dry cup;

film and composite

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ASTM E-96 Permeability Test

?Water cup method - determines how much moisture evaporates from the testing cup

?Dry cup method - determines how much moisture enters the testing cup

?Both methods can measure permeability of either the film of wallcovering or as a composite of the ‘wall sandwich’

Film Method

?Wallcovering film is mounted in holder?Either water or desiccant is added to the cup?Top is closed and weight is measured.?Total weight gain/loss is measured over 10

days?Calculations are made to determine perm

rating

E-96 Testing Apparatus

? Left - assembled cup? Right is unassembled

cup

Composite Testing

?Half inch drywall is coated with primer and allowed to dry

?Adhesive and wallcovering added and allowed to dry

?The additional steps are the same as the film method

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What about the results?

?None of the tests correlate well to each other

?Neither method is considered better?All comparisons must be compared utilizing

the same test method and using the same measuring units

How do the numbers compare from the different E-96 testing methods?

A comparison of a highly breathable wallcovering

?Film and wet cup - 60 perms?Film and dry cup - 50 perms?Composite and wet cup - 18 perms?Composite and dry cup - 10 perms

Permeability of various wallcoverings - film/water cup

?Type I - non-perforated: 2 perms or less ?Type II - non-perforated: 1 perm or less ?Type I – perforated: 12 - 18 perms?Type II – perforated: 7 - 15 perms?Highly breathable: 40 – 90 perms

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Permeability using- dry cup/composite testing

?Type I - non-perforated: less than 1 perm?Type II - non-perforated: less than 1 perm?Type I – perforated: 3 - 5 perms?Type II – perforated: 2 - 5 perms?Highly breathable: 8 - 15 perms

Installation of perforated or highly breathable wallcoverings

?Preferred method is dry hanging - to limit adhesive migrating through the wallcovering

?Both products can be installed using a roller pick-up type pasting machine

What else is being done?

? Primers - more breathable primers are being developed that have the same features and benefits

? Adhesives -formulated to better transmit moisture and enhanced mildewcides

? Wallboard - less permeable to keep moisture from entering the room as well as wallboard with the surface being made of fiberglass versus paper