Snow retention is more of a science than an art, factoring in physics laws to hold back thousands of pounds of snow and ice.
If done incorrectly, it can result in damaged property, injuries, and even loss of life. And getting it right entails factoring in the following:
- The snow load
- The roof’s slope
- The type of roofing material (asphalt, tile, metal)
- The fastening method used
- Sheathing type
- The load (weight of snow and ice) at a given space
Unfortunately, improperly installed snow retention bars fail every year, resulting in avalanches that cause property damage estimated in the millions.
In this article, we discuss some common snow retention bar installation mistakes to avoid.
1. Incorrect Layout
The layout of snow retention bars is a vital element in proper installation. In fact, The layout is the backbone of a snow retention system.
Often, caution is required because contractors will quote a few snow guards just so that they can win your interest with a low bid. The result is a poor layout that is sure to fail and, worse, the building owner facing liability.
A frequent layout mistake is placing a single row of bar near the eaves of the roof when multiple rows are required. Doing this gives the sliding snow and ice plenty of room to build up velocity, damaging the retention bars. It also allows for a lot of weight on the lower roof section near the eaves, causing an unbalanced structural load.
Another layout mistake is mounting a few retention bars in isolated areas such as the doors, entrances, and air vent stacks. Isolated placement of snow retention product has a high rate of failure.
The snow bars should be placed adequately all over the roof according to the manufacturer's recommended layout.
Obtaining a layout from the architect is another snow retention bar installation mistake. An architect’s drawings typically don’t factor in the building’s snow retention needs.
Therefore, rather than trying to get a layout from the architect, work with a snow retention systems manufacturer from the start to avoid snow retention bar installation mistakes. They will provide a more accurate drawing that includes what the building needs.
- Inquire about a warranty and only buy from someone who will stand by their model and will warranty the performance of the system.
- Remember, when it comes to layout, what your uncle, friend, or neighbor did on their roof doesn't count. You need a layout designed specifically for your roof and load factors to avoid snow retention bar installation mistakes.
2. Seam Skipping The Clamps
Another cause of failure is seam skipping. Clamps are the most expensive part of any bar system. Some manufacturers attempt to win bids by only providing clamps for every other seam. This results in weaker system strengths and increases the likelihood of failures in the future. It is easy to accept the lowest cost bid, but the reality is that you are actually buying alot less equipment and zero performance warranty. The greater the distance between clamps the more likely a bar will bend under load or a clamp will fail.
The most dependable systems supply clamps for every seam and also back the system by performance warranties to guarantee their long term success.
3. Poor Snow Retention Bar Design
Properly designed snow bar systems are strong and reliable, distributing the load equally across the whole roof. But due to budget concerns or ignorance, people often cut corners, resulting in the bar system failure.
One design mistake is having too few rows of bars resulting in force loads that are too high for the bars. This is often a result of failure to follow the suggested bar layout.
Remember, moving snow is much like a vehicle speeding downhill. And a few random bars placed with little or no consideration for the snow load, sheathing thickness, slope, or attachment pull-out rate can only hold the snow's weight for a while before coming apart.
Some roofs only require one row while others may require multiple rows spaced evenly up the slope. Manufacturers collect project data and run seam loading calculations to determine the best layout.
- Again, only work with a reputable manufacturer that offers a complete layout and warranty on the parts and performance.
- Opt for square bars and ensure you clamp them at every seam. Round bars tend to let the snow and ice to pass through.
4. Poor Product Quality
There's a wide variety of snow retention bar designs available in the market, and choosing one can get confusing.
A common mistake is to buy cheap imports and imitations with no regard for quality control, testing, layout, and warranty.
A good snow retention bar is made of quality materials such as extruded aluminum, stainless steel or galvanized steel, and has published independent test results to support it. Why the fuss about test results? Test results are vital for determining the rods' strength and the number of rows needed to control the snow load.
- To avoid having to reinstall snow retention bars, invest in a quality product from a reputable company.
- Ensure you ask for the test results and a warranty.
Now you have a better understanding of the snow retention bar installation mistakes you should avoid. We hope you find this information helpful in installing a robust and efficient bar system that outlasts your roof.