Winter 2023-24 marks Alpine SnowGuards 5th year of snow guard performance testing. Winter prep began last July for us when we retrofit two roofs with materials provided by composite tile pioneers DaVinci Roofscapes.

State-of-the-Art Tiles & Modern Snow Guard Choices

DaVinci’s roof tiles have the authentic look of hand-split natural shake and slate with the ability to endure any climate. They are constructed of a composite material made of virgin resins, UV and thermal stabilizers as well as a highly-specialized fire retardant. These engineered polymers make composite tiles slippier and prone to snow slides which gives Alpine the opportunity to innovate products geared toward this market.

DaVinci Multi-Width Shake with Fusion-Guard Snow Retention

 

 

 

 

 

Fusion-Guard was developed by Alpine in 2019 specifically for modern, composite tiles. It possesses a minimalist aesthetic that appeals to homeowners who are averse to pipe-style snow retention, yet want the benefits it provides. While we’ve included the optional rods in testing years prior, this year’s layout does not include rods. Advantages include:

• Pad design includes stiffening ribs on front that add rigidity and strength
• 18” strap can be custom cut and tucks securely under roof tile; easy to install on retrofit roofs, too
• 3″ snow guard head height is ideal for use in high snow load areas and with synthetic tiles with greater than 3/8” tile thickness
• Allowable snow load 300lbs per snow guard
• Extensively performance tested at our in-house facility

DaVinci Single-Width Slate with PD40 Snow Retention

 

 

 

 

 

PD40 is the ideal size for most asphalt shingle applications and is recommended for composite tiles that are <=⅜” thick. Testing will determine whether the PD40 can be recommended for DaVinci’s ⅝” thick roof tiles on lower slopes. Advantages include:

• Riveted “fish head” design for optimum strength with no risk of unfolding
• Can be mechanically attached through composite tile and fastens securely to structural roof decking
• 1 ½” high, cupped low-profile head; 6 ½” strap length
• Allowable snow load 250lbs per snow guard

Snow Retention Testing Goals

Alpine’s goals for testing snow retention systems for DaVinci’s composite tiles are two-fold: first, testing is an important factor of our recommended snow guard layouts; secondly, testing will help to determine which products perform best under a set of distinct variables. This knowledge will allow us to expertly advise customers on which systems will perform best for their application.

Importance of Following Manufacturer’s Recommended Layouts

Snow guards are safety devices and it’s important to follow a manufacturer’s recommended layouts to achieve maximum snow guard performance. To emphasize this, there are no reported failures of Alpine SnowGuards snow retention systems when they are properly installed. We provide free recommended layouts that benefit all parties involved.

Solutions to Stop Snow From “Slip Sliding Away”

“When a roof is covered in a smooth, ‘frictionless’ material like composite slate or shake roofs, the weight of the ice and snow becomes of much greater concern to the homeowner,” explains Alpine’s technical sales manager Kris Michaud. He goes on to say in DaVinci’s blog, How Much Snow and Ice Weight Can a Roof Hold, “This concern is not due to what the weight of the snow and ice will do to the roof structurally. Instead, the concern is what the force and weight of 6 tons of snow and ice will do when it avalanches off a roof.”

Snow Slide on Composite Tile Without Snow Retention

Without added snow guard protection, roofs will shed any snow accumulation once the temperature rises. When that happens, a meltwater layer is created between the roof surface and the snowpack, causing snow to predictably avalanche. To illustrate, here is snow sliding off a DaVinci Bellaforte Tile roof at our testing facility December 21, 2021 before snow guards were installed. We conservatively estimate 1,926 pounds of snow slid off based upon snow height, density and square footage in this video.

2023-24 Performance Testing
DaVinci’s Composite Tiles With Snow Guard Protection

DaVinci Multi-Width Shake and Fusion-Guard Snow Events & Performance

DaVinci Single-Width Slate and PD40 Snow Events & Performance

Temperatures are in Degrees Fahrenheit

SNOW EVENTS: Nov. 9-10, 2023

• Snowfall: 5:30 to 7 a.m. on Nov. 9
• Temperature: Temps rose from 28° to 32° by 12 p.m., Nov. 9 and stayed above freezing until 11 p.m., when temps spiked to about 40°. Some fluctuations throughout morning hours of Nov. 10, but temps rose over 40° and remained there after 7:00 a.m. until full melt occurred by 2 p.m.
• Humidity & Wind: 86%-88% with still wind (<5mph average)
• Total snow accumulation: less than the height of the roof separation joints, or less than 3”

PERFORMANCE: DaVinci Multi-Width Shake & Fusion-Guard 12:12 PITCH

• • Snow fell in a consistent blanket
  • Small portion of snow released at 8 a.m., another at 8:30 a.m. and by 8:45 a.m. most of the roof above the three-row snow guard pattern had cleared in a controlled manner. Remaining snow stayed in place through a full melt-out.

PERFORMANCE: DaVinci Single-Width Slate & PD40 7:12 PITCH

• • Snow fell in a consistent blanket and remained in place until full melt had occurred. No movement was witnessed on this roof.

SNOW EVENTS: Nov. 26-Dec. 6, 2023

• Snowfall: 10 p.m. on Nov. 26 to 7 a.m. on Nov. 27
• Temperature: Nov. 27 hovered at 32°-33° and began rising at 9 a.m., hitting a peak of 39° in the afternoon
• Wind: averaging ~10 mph
• Total snow accumulation: 3” on the roof
• Snowfall: 3:30 p.m. on Nov. 28 to 3:30 a.m. on Nov. 29
• Temperature:
  Nov. 28: 28°
  Nov. 29: 28° an overnight low of 21°
  Nov. 30: 32° at 10 a.m., 41° at 3 p.m. and an evening low of 30° saw some re-freezing occur before temps rose quickly over freezing
  Dec. 1-6: rose quickly above freezing by 5:30 p.m., reached a high of 45 by 2 a.m. on Dec. 2, at or above freezing until 2 p.m. Dec. 4, and below freezing through Dec. 6
• Wind: averaging 5-8 mph caused drifting snow on 12:12 PITCH and reduced
  accumulation on 7:12 PITCH
• Total Snow Accumulation: 3” on the roof; little appreciable movement of the snow other than densification with Nov. 29th’s overnight low; additional snowfall of approximately 1-1/2” fell the evening of Dec. 3 into the overnight hours

PERFORMANCE: DaVinci Multi-Width Shake & Fusion-Guard 12:12 PITCH

• • Snow built-up on the roof in a consistent blanket
  • Snow consistently released in small portions over time and the size of the release was consistent with the nature of the wet snow which lacked the structural capability to resist tearing. In other words, the snowpack was weak and susceptible to breaking apart.
  • As temps rose, meltwater reduced the friction bond between the snowpack and the roof
  • The weight load of the snow increased against the friction points of the snow guards until the snow tore itself apart around the snow guards
  • The three-row pattern worked well to hold up snow near the eave
  • Snow above and in the lower-density pattern worked free and slid down the slope, causing some snow around the three-row pattern to release as well
  • When temps remained below freezing and the snowpack had more integrity, the snow guards held all of the snow on the roof
    Additional snow guards upslope closer to the peak may increase the snow blanket’s ability to hold together by adding more friction points within the snow blanket

PERFORMANCE: DaVinci Single-Width Slate & PD40 7:12 PITCH

• • Throughout all 3 events, ideal snow management was achieved with snow gradually moving down the roof slowly and either melting out or falling in small pieces

SNOW EVENTS: Dec. 10-12, 2023

• Snowfall: Rain began Dec. 10 around 6 p.m. and turned to accumulating snow at 11:45 p.m. when the air temperature on our weather station read 33°. Snow continued off and on throughout Dec. 11 and ended about 6 a.m. Dec. 12.
• Temperature: Temps hovered around the 32° freezing point until about 5 p.m. on Dec. 11, before dropping to a low of 18° at 5:15 a.m. on Dec. 12, and rose to a high of 36° during the day.
• Total Snow Accumulation: Approximately 5-6″, Dec. 10-11.

SNOW EVENTS: Dec. 13-14, 2023

• Snowfall: Rain fell before turning into slushy ice/snow and snow accumulations.
• Temperature: Temps hit a low of 15° at 8:15 a.m. on Dec. 14, a high of 30° at 3 p.m. and an overnight low of 16°. Temps rose quickly heading into Dec. 15 with an afternoon high of 46°, stayed in the 30’s throughout the afternoon and rose back into the 40’s on Dec. 16.
• Total Snow Accumulation: Additional 1-2″, Dec. 13-14.

PERFORMANCE: DaVinci Multi-Width Shake & Fusion-Guard 12:12 PITCH

• • Snow built up on this roof in a smooth blanket
  • During the course of the snow fall, due to the wet nature of the snow and the steep slope, snow could not maintain its shape and began to slump downward against the snow guards
  • Snow solidified during sub-freezing temperatures the night of Dec. 11 into Dec. 12
  • More snow fell on Dec. 13 with no more slumping occurring
  • Snow stayed in place until small pieces fell during total melt-out
  • Performance: Excellent

PERFORMANCE: DaVinci Single-Width Slate & PD40 7:12 PITCH

• • Ideal performance again from this product.
  • Snow fell in a consistent blanket and was held in place on the roof area where the snow guards were located
  • The snow cap hanging over the ridge added a tensile strength to the snow pack, hanging onto the pitch transition at the ridge
  • Once snow separated from the ridge, the snow mass condensed and moved slowly down the slope into the area with snow guards over several hours
  • Meanwhile, snow slid off the metal separation barrier between the DaVinci roof and the asphalt shingle roof beside it continuously
  • Performance: Excellent

SNOW EVENTS: Jan. 6-24, 2024

• Snowfall: Jan. 6-8; calm, gentle breezes caused some wind drifting
• Temperature: Mid-20s falling to low-mid teens, rising to mid-high 20s
• Total snow accumulation: 6”-8”
• Snowfall: Jan. 9-10
• Temperature: High 20s to a high of 44°
• Total Snow Accumulation: 5”
• Snowfall: Jan. 11
• Temperature: Mid-20s to 31°
• Total snow accumulation: Less than 1”
• Snowfall: Jan. 13, calm winds to gentle breeze
• Temperature: Low 30s to low 40s
• Total Snow Accumulation: Less than 1”
• Snowfall: Jan. 14, light winds to gentle breeze
• Temperature: High 20s to 31°
• Total Snow Accumulation: 2”
• Snowfall: Jan. 16, calm winds to gentle breeze
• Temperature: 7° to 18
• Total Snow Accumulation: 3”-4”
• Snowfall: Jan. 17-22, calm to moderate wind
• Temperature: -2°-18°
• Total Snow Accumulation: 4” with slight additional accumulations
• Snowfall: Jan. 24, calm winds to light breeze
• Temperature: 21°-32°
• Total Snow Accumulation: Less than 1″
• Snowfall: Jan. 25-29
• Temperature: High 20s to low 30s, hovering around 31-32°, followed by low to high 20s 1/30-31
• Total Snow Accumulation: 5.5″-6″

PERFORMANCE: DaVinci Multi-Width Shake & Fusion-Guard 12:12 PITCH

• • A dry snow fell through the morning and into the day of Jan. 6, leaving a dusting of flaky snow on the shingle surface. 
  • A more substantial accumulation of 6” of dry, fluffy snow fell the evening of Jan. 6 into the day, Jan. 7
  • Due to the dry nature of the snow through Jan. 6, the snow pack lacked cohesiveness: it separated and a portion of the roof cleared, followed by another portion; however, the top of the roof snow held on
  • Additional snow accumulated over the course of the next couple of days along with settling of the snow and melt and re-freeze behavior. Snow began falling again in earnest on Jan. 10. The upper area that had the accumulated snow then released off the roof while the new fallen snow stayed in place until melt-out occurred the same day.
  • New snow January 14-15 fully melted out by end of day on Jan. 15 with no snow movement
  • Another snow event occurred Jan. 16 with 3-4” falling. The snow slumped and condensed but otherwise remained in place with additional accumulation Jan. 19-20.
  • Late in the day Jan. 20, the winds picked up and scoured the ridges, creating a drift on this roof. Slumping continued with snow beginning to move away from the ridge and around the snow guards through Jan. 23-24 when an additional dusting of snow accumulated
  • Persistent temperatures around 32° eventually saw the snow slide off the roof in one mass event at 9:20:20 on Jan. 24. The mass of the snow pack was simply too much for the viscosity of the snow. The snow tore off in chunks around the snow guards as the snow pack moved down the roof surface

• PERFORMANCE: DaVinci Single-Width Slate & PD40 7:12 PITCH

• • Snow built up starting Jan. 5 and remained in place as of midday, Jan. 31
  • No snow movement, though there was occasional wind scouring near the peak
  • Performance: Peak 

SNOW EVENT: February 13-15

• Snowfall: Approximately 4”
• Temperature range, avg: 11°-35°, 24°
• Humidity range, avg: 54%-88%, 72%
• Wind, range, avg: 0-16 mph, 6.5 mph
• Total snow accumulation: ~4”
• Notes: Frost formed and then snow fell the early morning hours of February 14th. Fully melted on February 15th with temperatures peaking at 28 degrees.

SNOW EVENT: February 15-16

• Snowfall: ~4”
• Temperature: 3°-27°, 18°
• Humidity: 43%-87%, 68%
• Wind: 0-12 mph, average of 40
• Total snow accumulation: ~4”
• Notes: Snow began around 8 PM on 2/15 and continued through the night to 7 AM on 2/16

SNOW EVENT: February 18

• Snowfall: ~1”
• Temperature: 13°-28°, 21°
• Humidity: 59%-81%, 69%
• Wind: 0-9 mph, 5 mph
• Total snow accumulation: ~1”

SNOW EVENT: February 26

• Snowfall: ~1”
• Temperature: 25°-41°, 32°
• Humidity: 56%-88%, 78%
• Wind: 0-7 mph, 2.5 mph
• Total snow accumulation: ~1”

PERFORMANCE: DaVinci Multi-Width Shake & Fusion-Guard 12:12 PITCH

• • Snow Event, 2/13-2/15: Several inches of snow built up on the roof behind the snow guards and was retained for 2 days until heavy melting occurred. During heavy melt, on the right-hand side where some drifting snow had accumulated a small section released in a controlled manner. The remainder of the roof melted off without further movement of the snow.
  • Snow Event, 2/15-2/26: ~4 inches of snow accumulated on the roof. In the morning hours ~10 AM the day following the snow event, the snow suddenly released from the roof. There was a significant snow drift at the peak. No frost accumulation was witnessed like it was in the hours prior to the 2/13 storm. The remaining days snow accumulated in small amounts and melted off.
  • Hypothesis: Frost formation on the shingles prior to snow falls seems to provide a seed for snow to bond to the roofing surface and create a higher co-efficient of friction, allowing the snow guards to work more effectively.
  • Performance: Mixed

PERFORMANCE: DaVinci Single Width Slate & PD40 7/12 pitch

• • Snow Event, 2/13-2/19: Snow accumulated on the roof and then was removed by wind and melt action. No sliding snow occurred during February.
  • Performance: Ideal

SNOW EVENTS: March 9-26

PERFORMANCE: DaVinci Multi-Width Shake & Fusion-Guard 12:12 PITCH

• • Snow Event, March 9-10: Several inches of snow built-up behind the snow guards, slumping heavily in the relatively warm, humid conditions during the snow fall event. Snow slumped around the snow guards, creating raised mounds. A small amount broke loose and slid off in a controlled manner. The remainder of the roof held during melt until it refroze going into the March 11-13 event.
  • Snow Event, March 11-13: Additional snow accreted behind and on top of the frozen precipitation that remained from the prior event. This event had more substantial drifting patterns. All snow stayed in place through melt-out, with some substantial slumping but no larger slides.
  • Snow Event, March 19: About 4 inches of snow fell over 8 hours from Midnight to about 8 AM. There was very significant drifting and wind scouring. Temperatures rose into the mid-20’s by 10 AM, continuing to the 30’s in the mid-afternoon. When the snow separated from the ridge cap on the left side of the roof, it overwhelmed the snow guards and slid off in a large mass. The remainder fully melted by mid-afternoon.
  • Snow Event, March 23-26: ~10 inches of snow accumulation. After about 7” of accumulation half of the roof lets go and about 10 minutes later the other half slides off. Snow re-builds up to about ~4 inches in depth, with significant drifting at the peak. Snow begins to migrate downward through pressure and melting until a large section of the snow pack breaks free. The remaining snow melts off.
  • Performance: Mixed

PERFORMANCE: DaVinci Single-Width Slate & PD40 7:12 PITCH

• • Snow Event, March 9-13: ~3” of snow built-up on the roof surface. The snow slumped in the relatively warm and humid conditions until melting completely on March 13.
  • Snow Event, March 19: ~4” of snow fell in a quick event. It melted out quickly with minor slumping and no snow slides.
  • Snow Event, March 23-26: About 10” of accumulated snow. Major wind scouring reduced the snow load in the upper 1/3rd. No snow slides.
  • Performance: Ideal

SNOW EVENT: April 3-April 8

• Snowfall: ~12 inches
• Temperature: 26° F -60° F, 36° F average
• Humidity: 25%-92%, 78% average
• Wind: 0 mph – 11 mph, 3 mph average
• Total snow accumulation: ~12 inches
• Notes: Snow fall was wet and appeared very heavy throughout the night of 4/3 and all day on 4/4 and into the early hours of 4/5.

PERFORMANCE: DaVinci Multi-Width Shake & Fusion-Guard 12:12 PITCH

• • Snow Event: April 3-April 8: ~12 inches of snow built up on the roof, slumping some during early snow fall and then building a fairly homogenous blanket of snow. The snow pack crept down the roof as it melted with no snow slides through complete melt-out.
  • Performance: Ideal

PERFORMANCE: DaVinci Single-Width Slate & PD40 7:12 PITCH

• • Snow Event: April 3-April 8: ~12 inches of snow built up in an even blanket then began to creep down the roof as it melted. No slides occurred through full melt-out.

Snow Retention Findings & Best Practices

After careful data analysis, we’ll share snow retention test findings here to shape future recommendations specific to our products. Please bookmark this blog to help inform your team on best practices as they relate to Alpine SnowGuards’ products paired with DaVinci Roofscapes.

Extensive Data Collection

Alpine collects extensive data 24-7 all across our 80 psf ground snow load performance facility in Morrisville, VT with a Weather Davis Station, 16 cameras on 12 roof types, and also conducts structural tests in-house.

For more information, check out:
“Alpine SnowGuards Installs New DaVinci Shake and Slate for 5th Year of Performance Testing”
“Performance Testing Alpine’s Snow Guards, Winter 2023-24”

We keep snow in its place

www.alpinesnowguards.com

info@alpinesnowguards.com 

888.766.4273

    

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Alpine SnowGuards designs, engineers, and manufactures snow management systems from our facilities in Morrisville, VT. We work closely with leading roofing contractors, engineering firms, developers, and roofing manufacturers to ensure we deliver quality products that do what we say they’ll do. Alpine SnowGuards can help a building qualify for LEED® credits.