Healthy and Affordable Housing Training
Practical Recommendations for Building, Renovating and Maintaining Housing
December 2001
Sponsored by the Asthma Regional Council of New England, U.S. Department of Housing and Urban Development, and U.S. Department of Energy

[Download printable PDF version]

Course Objective
Upon completion of this course participants will be able to:

• Describe the housing-based conditions that can trigger asthma attacks and other respiratory problems.
• Implement cost-effective design and building practices that can help minimize dust, mold, pests and poor indoor air quality which all contribute to respiratory illnesses.
  

Participants will also participate in a design clinic to obtain technical assistance on specific project design and construction issues.

Target Audience
The course is geared to those using public funds to construct, rehabilitate and/or maintain affordable housing. The information and techniques discussed in this course apply to work performed by architects, housing developers, project managers, housing financiers, insurers, and contractors. The course may also be of interest to health and environmental professionals.

Course Materials
The following materials are used when presenting this training.

• Presentation slides describing the connection between building conditions and asthma.
• Three technical pamphlets (distributed to students):
  > Recommended practices for design, rehabilitation, and construction of units
  > Recommended practices for maintenance & management of units, and for unit turnover
  > Recommended practices for resident education and operation of units.
• Supplies for exercises/activities (e.g., paper towel tubes and coffee stir sticks).
• Design drawings and project specifications provided by students.
  

Course Structure
The course is structured in three parts and is delivered over one and a half days.

Part 1: Introduction And Background On Asthma And Housing
The introduction provides an overview of the course structure. The background provides information on asthma and the linkage between asthma and building conditions. A PowerPoint presentation is available for this part.

Part 2: Building Housing That Minimizes Asthma Triggers – Technical Modules
These modules provide technical information on design and construction practices that can help minimize conditions triggering asthma and respiratory problems. The recommendations also help create durable structures. A series of pamphlets are available to provide more detail for this section and for use as student handouts.

• Module 1: Control Water and Minimize Moisture
• Module 2: Create and Maintain Effective Air Flow
• Module 3: Minimize Pests and Creatures
• Module 4: Minimize Dust
• Module 5: Control Combustion Gases
  

Part 3: Open Design Clinic
Trainers provide participants an opportunity to obtain technical assistance on specific project designs and issues. Participants are encouraged to bring in current drawings and project specifications.

The course is designed to allocate six hours of delivery time to Day #1 and requires approximately 8 hours total time for Day #1 with breaks and a one-hour lunch. The remaining 3 hours of delivery time is allocated to Day #2, with additional time for breaks. For classes with less technical background in construction and building components, the instructor may want to spend additional time covering the topics in Part 2 and shorten the design clinic.

Part 1: Introduction and Background on Asthma and Housing
(105 Minutes)

Introduction

• Introduce the course and sponsoring agencies.
• Introduce trainers.
• Provide an overview of the course schedule.
  

What Is Asthma?

• Asthma is a chronic disease of the medium and small airways of the lung.
• These airways are hypersensitive to certain “triggers” in the environment.
• Asthma can’t be cured, but we can control symptoms by minimizing environmental triggers and proper use of medication.
• Asthma attacks are allergic reactions to triggers or harmful exposures.
• Airways swell and fill with mucus, the muscles around the airways contract.
• Airways can collapse from excess swelling and spasm, causing shortness of breath and even death.
  
  

The Magnitude And Nature Of The Asthma Problem

• The number of Americans diagnosed with asthma has grown dramatically (13.7 million in 1993 and 17 million in 1998).
• The number of children diagnosed with asthma has nearly doubled in the past 12 years (2.8 million in 1983 to 5.3 million in 1995).
• We experience 3 million lost workdays and 10 million lost school days each year due to asthma.
• The number of deaths from asthma has increased over 50% in the past 20 years and over 75% in children under 19.
• Asthma is now the leading cause of hospitalizations for children after birth.
  

The Severity And Distribution Of Asthma Rates In New England

• In 1995, the Northeast experienced higher asthma rates than the South and West; both among the entire population and persons aged 5-34 years.
• Asthma disproportionately affects poor and minority children living in inner cities.
  * 11-12% of African American children have asthma compared to 8-9% of white children.
  * One public housing development in Boston found that 40% of adults and 56% of children surveyed reported asthma. A second study in Boston public housing found 26% of all residents reported experiencing asthma.
  * Many inner city neighborhoods report high rates of asthma hospitalization (Roxbury 19/1000 children) compared to a state average of 4/1000.
  * Hartford elementary schools reported 20-30% of children have asthma.
  

Asthma Causes and Triggers

• Dust and its components can cause asthma according to a recent medical review.
• Dust, molds, cockroaches, rats, mice, cats, and dogs are all factors that exacerbate asthma (‘triggers” for asthma attacks).
  

Dust Triggers Asthma

• Dust is the most common trigger for asthma in the US.
• Dust comes from dust mites, microscopic insects that shed their skin.
• Dust can also be tracked into homes or blown in through windows/doors.
• Dust is found in carpet, drapes, overstuffed furniture, and bedding.
  

Mold Triggers Asthma

• Molds are common irritants for asthma and other respiratory illnesses.
• Molds are frequently found around leaking plumbing, roofs, and water-damaged areas.
• Poor ventilation in bathrooms and kitchens can encourage mold growth.
• Basements without proper drainage or moisture control can cause mold growth.
  

Pests/Pets Triggers Asthma

• Pests and pests can spur allergic reactions and trigger asthma (cockroaches, mice, rats, cats, dogs).
• Even after pets are gone, their skin, hair and feces can remain and cause allergies.
• Asthmatic children allergic to cockroaches were more than 3 times as likely to be hospitalized if they were exposed to roaches in their home.
  

back to top

Part 2: Building Housing to Minimize Asthma Triggers - Technical Modules

Module 1: Control Water and Minimize Moisture
(2 hours)

Control Rain Water By Shedding Water Out From The Building

• Shed water from rain by layering materials to direct water down and out from building.
• Prevent leaky window and door systems. Install pan flashing under window and door gutters to direct water away from wall assemblies.
• Drain rain from roofs and exterior surfaces. Use gutters and overhangs.
• Minimize areas where water can collect. Ensure exterior claddings (clapboard, stucco, etc.) have drainage planes. Install cladding over furring strips. Back prime all painted surfaces to prevent absorption of moisture. Back vent brick veneers and install them over foam sheathings to disconnect the brick veneer moisture from the building. Install stucco over two layers of building paper or over an appropriate capillary break.
  

Control Groundwater Outside The House

• Concrete and masonry are water sponges, they wick water due to capillary action. Install capillary breaks on top of new concrete footings and the perimeter foundation wall (e.g., damp-proof the top of the footing or install a membrane).
• Use interior finishes that control moisture. Install semi-permeable rigid foam insulation on the interior assembly to protect interior finishes and to release the capillary water to the interior at a rate that does not produce mold.
• Slope ground away from buildings.
• Install exterior drainage systems. Top to bottom:
  * impermeable top layer of backfill;
  * free draining backfill or drainage board along foundation under top layer;
  * fabric filter below fill;
  * coarse gravel under fabric filter; and
  * perforated pipe under floor slab level piped to sump or daylight.
  

Minimize Plumbing Leaks

• Avoid putting plumbing in exterior walls. It is easier to detect and fix leaks in interior walls. Leaking plumbing in exterior walls (particularly insulated) can become a source of mold and water damage. Mold and structural damage is worse when leaks are not detected.
• Avoid using insulation products in bathrooms that when wet encourage mold growth. Plan for leaks, since leaks will inevitably occur in bathrooms (particularly wet areas behind tubs and showers). Paper faced gypsum board products and “green board” adsorb moisture. If such products are used keep them up off the floors at baseboard locations to minimize any water penetration upwards.
• Reinforce hose connections on clothes washers. Whenever possible, install washers in rooms with a drain and floor covering that is not water-sensitive.
• Install hot water heaters in rooms with a drain and floor covering that is not water sensitive. Heaters leak, particularly when they get old.
• Install shut off valves for clothes washers and hot water heaters to isolate them if they do leak. Valves should be accessible and visible.
  

Allow The Structure To Dry

• Construct walls using materials and techniques that let the wall dry to both the exterior and interior.
• Avoid using polyethylene as a vapor barrier because it does not allow any moisture in the vapor form to pass through. This traps moisture and can promote mold growth. Paper-faced cavity insulation can be used instead of plastic barriers. Cellulose cavity insulation is also effective in conjunction with gypsum board painted with two coats of interior latex paint. Interior polyethylene may make sense as a vapor barrier in severely cold climates (8,000 heating degree days or greater). Plastic vapor barriers used in below-grade wall assemblies in any climate prevent drying to the inside.
• Ventilate roofs to facilitate drying.
  

   

  back to top

Module 2: Create and Maintain Effective Air Flow
(1 hour)

Avoid Big Holes

• Big holes make it impossible to control air flows between indoor and outdoors and can promote condensation.
• Design and construct basements to be dry and not serve as a hole to the outside. Insulate basements at the perimeter, not only between floors.
• Seal air flows near bathtubs and shower enclosures with rigid materials (e.g., sheathing or gypsum board). Cavity insulation is not sufficient to stop airflows.
• Avoid putting leaky duct work and air handlers in attics that are vented to the outside. Whenever possible, avoid placing dust work etc. in attics or exterior walls since they can cause ice-damming problems.
  

Eliminate Cold Surfaces To Avoid Condensation

• A key strategy to eliminating condensation is to minimize cold surfaces.
• Make windows warm. Install double glazed windows with non-thermally conductive frames (no metal windows). Avoid aluminum extrusion windows. Ideal frames are wood, vinyl, or fiberglass. Severe climates should use low E windows.
• Minimize the use of metal studs. They are prone to condensation. Metal studs pose particular problems in exterior walls with cavity insulation as the moisture/condensation on studs can promote mold growth within the insulation. If metal studs are used, limit them to interior walls or the interior of rigid wall assemblies (on interior side of rigid insulation on exterior wall). Metal studs pose severe problems below grade unless they are separated from slabs with thermal breaks and from foundation perimeters with rigid insulation.
• Use insulation in basements that is not water-sensitive and prevents warm interior air from contacting cold basement surfaces. Foam-based and semi-permeable materials are effective at allowing wall assemblies to dry to the inside.
• If basement spaces are designed for occupation, install continuous rigid insulation under concrete floors to raise the temperature of the floor covering. Rigid insulation could also be installed above the concrete floor slabs with a floating floor.
  

Maintain Appropriate Indoor Humidity And Minimize Airborne Contaminants

• Control indoor humidity to avoid excessive moisture that promotes molds and ventilate unhealthy airborne gases.
• Spot ventilation exhausts specific sources of contamination and humidity (kitchen and bathrooms).
• Dilution ventilation addresses low level contamination throughout the home.
• Install fans that exhaust to the outside in kitchens and bathrooms. Kitchen fans exhaust moisture, odors, and other contaminants (e.g., gas stoves).
• Fans should be durable and quiet (less than 3 sones).
• Ideal humidity is 30%-60%. You can measure humidity with an inexpensive hygrometer.
  

back to top

Module 3: Minimize Pests and Creatures
(1 hour)

Keep Pests Out Of The Home

• Block pest entries and passages.
• Seal utility openings and joints between materials. Use corrosion-proof materials such as copper or stainless steel mesh. Rodents can move through many materials and squeeze through tiny openings.
• Keep bushes and trees away from foundations. Bushes and trees near a home can provide food, living space, and sheltered passage for rats, mice, birds, roaches and ants.
  

Limit Food And Water

• Make sure food storage areas are dry and ventilated.
• Make trash storage areas dry and well ventilated.
• Minimize moisture that attracts creatures (see moisture section).
• Wash bedding, stuffed animals, and upholstered furniture to kill dust mites and wash away allergens. Bedding, stuffed animals, and small items can be cleaned in hot water with soap (greater than 130 degrees Fahrenheit). Hot water extraction systems can be used on furniture provided extra care is taken to remove water that might promote mold growth.
  

Use Integrated Pest Management (IPM) Strategies If Needed

• Dusting with boric acid in inaccessible locations can control roaches.
• Apply any pesticides directed to the surfaces requiring treatment, avoid spraying pesticides.
  

back to top

Module 4: Minimize Dust
(30 minutes)

Control Dust At The Entry

• Over two-thirds of dust in homes originates outside and is tracked inside on feet.
• Stop dust at the door. Vacuum and filter remaining dust. Make surfaces smooth and cleanable.
• Design entryways with:
  * Permeable, rugged, outdoor mats to collect gritty materials or a grate over a collection hole;
  * Rugged indoor mats that collect grit and water; and
  * A hard, smooth surface that is cleanable (vacuumed and mopped to collect fine particles).
  

Create Cleanable Surfaces

• Avoid using carpets in wet or humid areas (e.g., entryways, bathrooms, kitchens).
• Use window treatments that can be vacuumed and washed (e.g., blinds).

Use Filtering Strategies

• Construct a tight building enclosure to keep out dust and provide filtration.
• Filter should be MERV 6-8 (35 percent or better ASHRAE dust spot efficiency).
  

back to top

Module 5: Control Combustion Gases
(30 minutes)

Vent Combustion Appliances

• Gas cook tops and gas ovens create products of incomplete combustion. Use exhaust ventilations systems (to the outside) with gas cooking appliances.
• Whenever possible, use sealed combustion power vented devices (gas furnaces, gas boilers, and gas water heaters).
  

Vent Garages

• If garages are attached to homes, vent to the exterior with a passive vent stack.
• Do not locate air-handling devices (furnaces, air conditioners) in garages.
• Use weather-stripping on the door between the garage and home to minimize air flow.
  

Part 3: Open Design Clinic
(2 hours)

Instructors should collect questions, drawings, and specifications from students at the end of Day #1. During this part of the course, the instructor answers student questions (referring to the student-provided drawing and specifications as necessary) for the entire class so that all students can learn from the examples.

back to top