National Tribal Forum on Air Quality Co-Sponsored by: Institute for Tribal Environmental Professionals & National Tribal Air Association

New Construction Methods & Mold Prevention Steve Klossner

New Construction Methods & Mold Prevention What are we building? – Healthy/Durable/Efficient Useful life of our buildings Moisture management Maintenance requirements and responsibilities First costs driven construction methods No performance requirements

Oversight requirements Innovative and durable design takes additional resources during construction – From the design team – From the builder – From all subcontractors – From the building owners A process for making sound decisions on site

Wall cavity insulation Why do we insulate wall cavities? What happened when we added insulation?

Winter relative humidity Can be maintained with flow thru humidifier – MUST HAVE OUTSIDE RESET Current practice (fear of winter RH) generally precludes these from being installed

Summer relative humidity Can only be controlled with air conditioning system or dehumidification – Dehumidifiers cost as much as air conditioning to operate – Dehumidifiers add heat to the home Most basements and crawl spaces are at or below the dew point for the RH in summer – Guarantees mold growth

Rank Order Pen/Asp From all Minnesota Tribal Houses

First up is moisture management When you dig a hole and the whole fills with water you have? A. A swimming pool B. A well or cistern C. Wet foundations D. A crawl space or basement

Wet Foundations

13 Moisture Source

If it is not a boat, it won’t float!

Water proofing

Basement Insulation

Above Grade Construction Considerations Are we building our houses too tight? Are we putting too much insulation in our walls and ceilings? Are our air handlers tight enough to not generate interstitial pressure problems?

Air Flow Management Unfiltered air leaking through a typical 2,000 square foot house due to wind, stack effect, leaky ducts, and unbalanced air distribution systems. – 900 CFM during very cold windy weather. – 300 CFM average during the year. – 30 CFM during mild weather and low wind.

House Wrap Proper as Specified

House Wrap Application as installed

A different approach Vapor Retarder Drainage Plane

R-10 Rigid Insulation (Outperforms R-19 cavity insulation)

Drainage behind siding

Heat and Energy Recovery Ventilation With high fuel costs would seem appropriate – Energy recovery rates from 60-90% Increases the temperature of inlet air – Significant for occupant comfort Has significant maintenance requirements – Or becomes exhaust only or worse no ventilation

Outside exhaust hoods (Installation)

Outside air inlets (maintenance)

When hoods get blocked... (maintenance)

Outside exhaust hoods (maintenance)

Outside air inlets (maintenance)

HRV (Maintenance)

HRV Filter (maintenance)

Ventilation Controls

Ventilation Maintenance Not just for HRV’s

So for ventilation... Simple is best HRV’s only if we are willing and able to complete maintenance requirements – Monthly for filters – Quarterly for air inlets – Bi-yearly for core ERV’s with above maintenance AND – Capillary breaks – Water proofing

Filtration Primarily for IAQ we need to be concerned with smaller particles Most low cost furnace filters will not capture these MERV rating of 10 or greater is appropriate for IAQ To filter the air, the air handler has to be in operation – Same requirements as ventilation distribution

Particle Settling Velocities Particle Size (microns)Settling Velocity feet per minute feet per minute inches per minute 15.1 inches per minute inches per hour inches per day <0.1negligible Source: AAF

Filtration & Air Handler Operation Care must be taken when choosing high efficient filtration – 1” filters tend to have high static pressure Number 1 cause of compressor failure Will cause short cycling in heating season (efficiency) – Maintenance requirements for 1” filter are higher Four inch filter with pressure sensor is the sliced bread of residential filtration

How to Move Forward Measurable, quantifiable, specifications seems to be one of the ways we should be moving. – Interior relative humidity – Shell tightness (whole building) – Ventilation Measured flows Distribution Operating costs and system efficiencies Maintenance issues and costs

Closing Thoughts We need to spend more time evaluating what works and what does not work in housing ($) If we understand what is “broke”, we can fix it and design it out of the next project. – If we don’t we will simply perpetuate the problem or spend monies on inappropriate fixes The solutions are out there, we simply need to find and adopt them!

Thanks! Questions or Discussions?