Hail and Wind Mitigation Strategies

Colorado’s frequent hailstorms impact roofing systems, windows, and rooftop mechanical systems in multifamily developments. The IBHS FORTIFIED™ standard provides a robust framework to mitigate risk from hail and wind damage.

Roof Design and Materials

• Class 4 Impact-Resistant Shingles: Incorporating Class 4 impact-resistant shingles rated as "good" or "excellent" by IBHS enhances durability.

• Roof Slope Design: Steeper roof slopes help minimize the force of hail impact and improve drainage. In contrast, flat or low-slope roofs are prone to pooling water and impact damage. To address this, elastomeric coatings and reinforced membranes can be applied to flat or low-slope roofing systems for added resilience. Features like parapet walls and overhangs add more protection.

• Durable Roofing Options: When budgets allow, durable materials such as metal or composite roofing are ideal for long-term resilience.

Windows and Skylights

• Impact-Resistant Glass: Laminated or tempered glass rated for impact resistance reduces vulnerabilities.

• Window Films: Durable window films help prevent shattering.

• Roll-Down Shutters: For larger openings, roll-down shutters provide an additional layer of security during extreme weather events.

Mechanical Systems

• Protect Rooftop Equipment: Metal cages or louvered screens shield these systems from hail damage without compromising airflow.

• Specify Hail Resistance Components: Hail-resistant condenser coils, reinforced fins, or highly durable protective fins extend the lifespan of HVAC equipment. Similarly, hail-resistant solar panels with tempered glass and sturdy mounting systems positioned at optimized angles can prevent direct impacts and protect nearby infrastructure.

Retrofit Opportunities

Retrofitting existing structures offers a cost-effective way to enhance resilience. Upgrading older roofs to Class 4 impact-rated materials and installing protective membranes on flat roofs reduces vulnerability to hail. Adding window films, hail guards for HVAC units, and more durable siding materials strengthens building envelopes against future storms.

Wildfire Mitigation Strategies

In wildfire-prone regions, multifamily housing faces significant risks from embers, radiant heat, and combustible materials. Implementing the following strategies can reduce ignition risks, enhance resident safety, and support compliance with Wildland Urban Interface (WUI) codes. The FORTIFIED Wildfire™ program, while oriented to single family homes, also provides a useful mitigation framework.

Non-Combustible Materials and Building Design

• Non-Combustible Materials: Utilize materials such as fiber cement siding, stucco, and Class A fire-rated roofing to improve fire resistance and reduce ignition risks.

• Ember-Resistant Vents: Fine mesh screens or baffles prevent embers from infiltrating attics and crawl spaces, while sealing soffits, eaves, and roofing edges with non-combustible materials eliminates potential entry points.

Ventilation and Air Quality

• Air Sealing: Maintaining a tight building envelope through high-performance weather stripping and caulking minimizes air leaks and smoke infiltration.

• Energy Recovery Ventilators (ERVs): Positive indoor air pressure, supported by energy recovery ventilators and MERV 13+ filters, protects indoor air quality during wildfire events. This envelope and ventilation system approach also synergizes well with an all-electric design, helping to reduce utility operating costs.

Landscaping and Defensible Space

• Defensible Zone: Landscaping plays a critical role in fire mitigation. Establishing defensible zones around buildings, such as a five-foot buffer with non-flammable materials, reduces the likelihood of fire spread. Incorporating fire-resistant vegetation and landscape designs compliant with local codes enhances this protection.

• Engaging Local Fire Departments: Collaborating with local fire departments during development ensures emergency access and compliance with defensible space requirements.

Emergency Systems and Pathways

• Emergency Systems and Egress Pathways: Fire-rated doors and clear, unobstructed stairwells facilitate safe evacuation. Equipping units with fire extinguishers, alarms, carbon monoxide detectors, and emergency kits—complete with N95 masks and smoke hoods—prepares residents for wildfire scenarios.

Renewable Energy Systems

• Renewable Energy Systems: Solar panels with fire-resistant tempered glass and non-combustible mounting systems minimize fire risks while providing backup power during outages.

• Battery Storage Systems: Backup storage ensures critical HVAC functions and indoor air quality remain operational when grid power is compromised.

Retrofitting Existing Structures

For existing structures, replacing combustible materials with alternatives like fiber cement siding and metal roofs strengthens a building's resilience to embers and radiant heat. Sealing vents, soffits, and windows, and reinforcing decks, balconies, and fences with fire-resistant materials, further protects against wildfire hazards.

Flood Mitigation Strategies

Flooding poses significant risks to building foundations, lower-level units, and shared mechanical systems. The following strategies focus on design, materials, and systems to reduce these risks.

Site Design and Grading

• Site design: Consider grading that slopes away from building foundations, channeling water toward storm drains or natural drainage areas. Features such as berms and swales can also direct runoff safely away from structures.

• Building Elevation: Elevating buildings above the base flood elevation (BFE) using stilts, raised foundations, or platforms protects structures and ensures critical systems like utility meters, HVAC units, and electrical panels remain above flood levels.

Water Runoff Management

• Permeable Materials: Permeable surfaces such as porous pavement for parking lots and pathways enhance infiltration, while green infrastructure like rain gardens and bioswales absorbs and filters stormwater.

• Reinforced Foundations: Foundations built with concrete or masonry withstand hydrostatic pressure, and foundation vents allow controlled water flow to reduce pressure during floods.

• Retention Basins and Detention Ponds: Retention basins temporarily hold stormwater for gradual release, while detention ponds slow runoff to reduce peak discharge rates.

Flood-Resistant Materials

• Flood-Resistant Materials: Selecting durable materials such as concrete, tile, and closed-cell foam insulation for lower levels enhances a building’s ability to withstand water exposure and minimize long-term damage. In flood-prone areas, replacing traditional drywall with moisture-resistant gypsum board helps prevent mold growth and structural deterioration, improving overall building longevity and safety.

• Sealing and Waterproofing: Sealing building exteriors with waterproof coatings and membranes prevents water penetration, while watertight shields and panels protect openings during flood events. In some cases, designing lower levels to allow controlled water entry reduces structural pressure and simplifies cleanup, especially when paired with removable flooring and modular furniture.

Utility System Protection

• Relocating Utility Systems: Relocating electrical panels, water heaters, and HVAC equipment to higher levels reduces vulnerability. Waterproof cabinets offer further protection for critical systems.

Retrofitting Existing Structures

For existing structures, raising electrical outlets and switches above predicted flood levels, reinforcing walls with flood-resistant materials, and applying waterproof coatings to foundations can significantly reduce damage. Temporary flood barriers around building perimeters offer additional defense during storm events.

Drought Mitigation Strategies

Drought resilience strategies not only address water scarcity in Colorado’s arid climate but also lower water and sewer operating costs, contributing to long-term affordability. These measures integrate resource-efficient approaches in landscaping, irrigation, and water use to support sustainability without compromising functionality or aesthetics.

Water-Wise (Low Water/Water Efficient) Landscaping and Non-Functional Turf

In accordance with the CHFA Housing Tax Credit Allocation Plan, new construction projects shall meet design codes and apply “Water-Wise” landscaping techniques that limit irrigated turf to promote quality of life and climate resilience. This includes water- and plant-management practices that:

• Are designed with shrubs, perennials and warm-season grasses with an annual irrigation water requirement of less than 15” (9.345 gallons per square foot);

• Are intended to be functional and attractive;

• Emphasize the use of plants that require lower supplemental water, such as native and drought- tolerant plants; and

Prioritize the following key principles:

• Planning and design for water conservation, beauty, and utility;

• Improving soil;

• Applying efficient irrigation;

• Limiting turf to high traffic, essential areas;

• Selecting plants that have low water demand;

• Applying mulch; and

• Maintaining the landscape.

Efficient Irrigation Systems

• Advanced Irrigation Systems: Responsive irrigation systems make watering more efficient by adjusting to real-time needs. Weather-based controllers schedule watering based on current weather and soil moisture levels. Timers and sensors prevent overwatering during rainfall, and adjustable emitters ensure plants with varying needs receive appropriate amounts of water.

• Drip Irrigation Systems: Drip systems deliver water directly to plant roots, minimizing evaporation and runoff.

Water-Efficient Fixtures

• Water-Efficient Fixtures: Inside buildings, water-efficient fixtures further reduce water use. EPA WaterSense-labeled faucets, toilets, and showerheads lower consumption without sacrificing performance, reducing utility costs and supporting conservation goals.

Extreme Temperature Mitigation Strategies

Colorado’s extreme heat and cold events place significant demands on building systems, elevate energy costs, and can pose risks to resident safety. While extreme cold can pose a challenge to the performance of all-electric building designs, integrating high-performance thermal envelope assemblies, appropriately-sized advanced HVAC systems, and on-site renewable energy solutions can create housing that withstands temperature extremes while maintaining indoor comfort and energy efficiency.

High-Performance Thermal Envelope

• High-Performance Insulation: High R-value insulation in walls, roofs, and floors minimizes heat transfer, ensuring consistent indoor comfort.

• Reducing Thermal Bridging: Continuous insulation and thermal breaks can be used to eliminate thermal bridging.

• Glazing and Thermal Breaks: Low-E, double-glazed windows reduce heat transfer and solar gain while preserving natural light, and thermally broken frames enhance overall insulation.

• Air-Sealing and Blow Door Testing: Air-sealing the building envelope with high-quality membranes, tapes, and gaskets reduces drafts and outdoor pollutant infiltration. Blower door testing ensures compliance with airtightness standards, optimizing energy efficiency.

Shading Systems

• Shading Systems: Fixed or adjustable shading features like overhangs or exterior blinds adapt to seasonal variations and help manage solar heat gain, while deciduous shade trees planted near southern and western exposures block summer heat and allow winter sunlight to warm the building.

Green Roofs

• Reducing Heat Transfer via Green Roofs: Green roofs feature layers of vegetation installed atop building roofs, incorporating a growing medium, drainage system, and waterproof membrane. These systems provide natural insulation, reducing heat transfer into buildings during summer and minimizing heat loss during winter.

• Reducing Runoff and Air Pollutants via Green Roofs: In addition to improving thermal performance, green roofs filter pollutants, absorb carbon dioxide, and enhance air quality. They also alleviate stress on urban drainage systems by absorbing rainfall and reducing runoff.

Cool Roofs and Pavement

• Cool Roofs and Pavement: Cool roofs and pavement mitigate extreme temperatures by reflecting sunlight and reducing heat absorption. Both systems use light colored and reflective materials to lower indoor temperatures, decrease air conditioning needs, and reduce energy costs.

Efficient HVAC Systems

• Cold Climate Heat Pumps: HVAC systems should be thoughtfully designed for extreme conditions. Cold-climate heat pumps with appropriately designed envelopes and auxiliary heat can efficiently provide heating and cooling, even during sub-zero temperatures.

• Energy Recovery Ventilation (ERV) or Heat Recovery Ventilation (HRV): ERVs and HRVs can reduce the heating loads associated with building ventilation while maintaining high indoor air quality and lowering energy costs.

• Renewable Energy Systems: All-electric design in outage prone areas can benefit from integrating on-site solar photovoltaics with battery storage, offering backup power during outages and supporting uninterrupted HVAC operation. These systems can also smooth out electric demand peaks to reduce utility costs.