Are you trying to choose between open vs closed roof valley systems for your home? This decision affects both your roof’s appearance and how well it protects your house from water damage. Understanding the differences between open vs closed roof valley systems helps you make the best choice for your specific needs and budget.
What Are Roof Valley Systems?
Roof valley systems form where two roof slopes meet, creating a V-shaped area that channels water off your roof. These valleys are critical parts of your roofing system because they handle large amounts of water during storms. When comparing open vs closed roof valley systems, the type of valley you choose affects how well your roof prevents water damage and how long it lasts.
There are two main types of roof valleys when considering open vs closed roof valley systems:
- Open roof valley systems that show the metal flashing
- Closed roof valley systems that hide the valley under shingles
Understanding Open Roof Valley Systems
Open roof valley systems expose the valley lining, which is usually made of metal flashing. Here’s how roofers install an open valley:
- Install underlayment: Roofers start with self-adhering underlayment for extra protection
- Add metal flashing: They install metal lining like galvanized steel, aluminum, or copper
- Place shingles: Shingles go next to the metal lining but don’t cover it
- Create water channel: This leaves a visible channel that directs water flow
Benefits of Open Roof Valley
Open valley roofing offers several advantages:
- Better water flow: The exposed metal channel moves water quickly off your roof
- Less debris buildup: Leaves and debris wash away more easily
- Easier maintenance: You can see and clean the valley more easily
- Longer lifespan: Metal flashing lasts longer than shingles
- Better leak prevention: Less chance of water getting under shingles
Open Valley Materials
The flashing material you choose affects both cost and performance:
Galvanized Steel Flashing:
- Most affordable option
- Good durability for most climates
- May rust over time in wet areas
Aluminum Flashing:
- Lightweight and rust-resistant
- Good for most homes
- More expensive than steel but less than copper
Copper Flashing:
- Premium choice with excellent longevity
- Develops attractive patina over time
- Most expensive but can last 50+ years
Understanding Closed Roof Valley Systems
Closed roof valley systems hide the valley completely under shingles. This creates a smooth, uniform look across your entire roof. Here’s how closed valley systems work:
- Thick underlayment: Roofers use extra-thick self-adhering underlayment
- Shingle installation: Asphalt shingles extend across the valley
- Seamless appearance: The valley blends with the rest of your roof
- Water protection: The underlayment provides the main water barrier
Types of Closed Valley Systems
There are two main types of closed valley systems:
Woven Valleys:
- Shingles from both roof slopes weave together over the valley
- Creates the most seamless look
- Requires skilled installation to prevent leaks
Cut Valleys:
- Shingles from one side extend past the valley center
- Shingles from the other side are cut to fit
- Easier to install than woven valleys
Benefits of Closed Valley Roof
Closed valley roof systems offer these advantages:
- Clean appearance: Creates a smooth, uniform roof look
- Lower material costs: No metal flashing material needed
- Traditional style: Works well with most home styles
- Good performance: When properly installed, provides excellent protection
Comparing Open vs Closed Roof Valley Systems Performance
When evaluating open vs closed roof valley systems, performance differences become clear in several key areas.
Water Management
Open Roof Valley:
- Water flows faster through the exposed metal channel
- Less likely to back up during heavy rains
- Debris washes away more easily
- Better for areas with heavy rainfall or snow
Closed Roof Valley:
- Water must flow over and through shingles
- May collect debris more easily
- Requires proper installation to prevent water backup
- Works well in moderate climate conditions
Durability and Lifespan
Open Valley Lifespan:
- Metal flashing can last 30-50+ years depending on material
- Copper flashing may last 50-100 years
- Less likely to develop leaks over time
- Easier to inspect for problems
Closed Valley Lifespan:
- Depends on shingle quality and installation
- May need replacement when roof is replaced
- Harder to inspect for underlayment problems
- More vulnerable to installation errors
Maintenance Requirements
Open Valley Maintenance:
- Easy to inspect and clean
- Visible problems are easier to spot
- Simple to repair individual components
- Less frequent maintenance needed
Closed Valley Maintenance:
- Harder to inspect for problems
- May require removing shingles for repairs
- Problems may not be visible until damage occurs
- Regular inspection important to prevent issues
Cost Comparison: Open vs Closed Valley Systems
Understanding the cost differences between open vs closed roof valley systems helps you budget effectively for your roofing project.
Initial Installation Costs
Open Valley Costs:
- Metal flashing materials: $3-8 per linear foot
- Installation labor: $5-12 per linear foot
- Premium metals (copper) can cost $15+ per linear foot
- Total: $8-20+ per linear foot
Closed Valley Costs:
- Extra underlayment: $1-3 per linear foot
- Additional shingles: $2-5 per linear foot
- Installation labor: $4-8 per linear foot
- Total: $7-16 per linear foot
Long-term Cost Considerations
Open Valley Long-term Costs:
- Lower maintenance costs
- Longer replacement intervals
- Easier repairs when needed
- Better value over 20-30 years
Closed Valley Long-term Costs:
- May need more frequent maintenance
- Replacement needed with roof replacement
- More expensive repairs if problems develop
- Potentially higher long-term costs
According to the National Roofing Contractors Association, proper valley installation is critical for preventing water damage, regardless of which type you choose.
Aesthetic Appeal: Choosing the Right Look
Open Valley Appearance
Open roof valley systems create a distinctive look:
- Metal flashing adds visual interest
- Can complement modern or traditional styles
- Copper develops beautiful patina over time
- Creates defined roof lines and sections
Closed Valley Appearance
Closed valley roof systems offer:
- Smooth, continuous roof appearance
- Traditional residential look
- Blends seamlessly with roof surface
- Works well with most architectural styles
Climate Considerations for Valley Choice
Hot, Sunny Climates
In areas like Southern California:
- Open valleys with reflective metals can reduce heat absorption
- Metal flashing handles thermal expansion better
- Less UV damage to valley area
- Copper or aluminum work well
Cold, Snowy Climates
In northern regions:
- Open valleys shed snow and ice more effectively
- Less ice dam formation in valley areas
- Metal flashing handles freeze-thaw cycles better
- Important for preventing winter damage
Wet, Rainy Climates
In high-rainfall areas:
- Open valleys handle heavy water flow better
- Less debris collection and clogging
- Easier to maintain and clean
- Reduces risk of water backup
According to the International Code Council, proper valley design becomes even more critical in areas with severe weather conditions.
Installation Quality Matters
Professional Installation Requirements
Both open and closed roof valley systems require skilled installation:
- Proper underlayment application
- Correct flashing material sizing and placement
- Attention to shingle cutting and fitting details
- Understanding of local building codes
Common Installation Mistakes
Open Valley Problems:
- Improper flashing width or placement
- Poor shingle cutting along valley edges
- Inadequate underlayment overlap
- Wrong fastener types or placement
Closed Valley Problems:
- Insufficient underlayment thickness
- Poor shingle weaving or cutting
- Inadequate water testing during installation
- Rushing installation without proper attention to detail
Choosing the Right Roofing Contractor
When selecting a contractor for valley installation:
- Look for experience with your chosen valley type
- Ask for examples of previous valley work
- Verify proper licensing and insurance
- Check references and online reviews
- Get detailed written estimates
The Better Business Bureau recommends getting at least three quotes and checking contractor credentials before making your decision.
Making Your Decision: Open vs Closed Valley Systems
When choosing between open vs closed roof valley systems, consider these factors when making your final decision:
Choose Open Valley Systems If:
- You live in an area with heavy rainfall or snow
- You prefer distinctive, defined roof lines
- Long-term durability is your top priority
- You want easier maintenance and inspection
- Your budget allows for premium materials
Choose Closed Valley Systems If:
- You prefer a smooth, uniform roof appearance
- Initial cost is a primary concern
- Your roof has moderate water flow requirements
- You want a traditional residential look
- You have a skilled contractor experienced with closed valleys
Conclusion
Both open vs closed roof valley systems can provide excellent protection when properly installed. When comparing open vs closed roof valley systems, open roof valley systems typically offer better water management and longer-term durability, while closed valley systems provide a cleaner appearance at a lower initial cost.
The best choice between open vs closed roof valley systems depends on your climate, budget, aesthetic preferences, and long-term maintenance goals. Working with an experienced roofing contractor helps ensure whichever roof valley system you choose will protect your home effectively for many years.
At Horizon Roofing in Anaheim, CA, we have extensive experience with both open and closed roof valley systems. As certified Owens Corning Preferred Installers and GACO Silicone Installers, we build roofs that exceed industry standards. Our leak-free guarantee and 5-year warranty on repairs ensure your roof valley system will protect your home year after year.
Need help choosing the right valley system for your roof? Contact Horizon Roofing at (714) 328-1967 for expert advice and professional installation services.