Do I need snow guards on a metal roof? The short answer is that guards address one specific risk: snow and ice sliding off a sloped roof. Whether your roof needs them depends on its layout and the snow it must carry, and that call belongs to a qualified professional.
Snow guards are attachments that stop snow from sliding off a sloped roof. A 1997 IIBEC paper says sliding snow and ice can damage property, kill people, and overload lower roofs. Whether your metal roof needs guards depends on its layout and snow load, so a qualified professional should make that decision.
What Sliding Snow Does on a Metal Roof
Sliding snow can damage more than the roof itself, according to a 1997 IIBEC paper by Tobiasson, Buska, and Greatorex. The paper says sliding snow and ice can damage property, kill people, and overload lower roofs. It describes snow guards as obstructions attached to the roof that prevent snow from sliding.
The same paper reports that plumbing stacks and other roof penetrations have been displaced or sheared off by sliding snow. Those are the kinds of parts a roof plan should account for when snow can reach them.
Figure 1 shows the sequence in four steps. Snow builds on the slope, slides down the panels, reaches the eave, and lands on the lower roof or the ground below.
This article covers need and risk. For a guard count, the snow guard count calculator does the arithmetic. The worked example later in this article shows the same steps by hand.
Why a 1997 Paper and a 2025 Blog Differ
The two sources agree that sliding snow is a risk, but they differ in age, source type, and tone. Read the older paper for the risk itself. Read the newer blog as a product maker’s view.
When you compare the two, check the date first and the purpose second. A 1997 technical paper and a 2025 product blog serve different readers, so the same claim can carry different weight in each.
The IIBEC paper is old: it dates from January 1997. It calls for improved design guidelines, standards, and performance criteria for snow guards on metal roofs. No newer standard was verified for this article, so treat the paper as background, not as current design rules.
The Rocky Mountain Snow Guards blog, dated 7 July 2025, is a commercial source written by a snow guard manufacturer. It argues that without guards, snow and ice can slide off sloped roofs suddenly. This article does not use its injury or damage claims.
| Attribute | IIBEC paper (1997) | Manufacturer blog (2025) |
|---|---|---|
| Source type | Technical paper | Commercial, from a snow guard maker |
| Age at this update | Nearly 30 years old | About 16 months old |
| View of guards | Guards prevent sliding; better standards are needed | Without guards, snow can suddenly slide off |
| Use in this article | Used for the sliding snow risk and the call for standards | Used for its stated position only; injury and damage claims not used |
Read the two together. The paper asks for better standards, and the manufacturer treats guards as the fix for sudden slides. Neither source gives a verified rule for your roof, so the decision needs your own roof and snow load in mind.
The Three Snow Guard Categories
Snow guard products fall into three categories: pad-style units, pipe or rail systems, and fence-style guards. These names come from the calculator’s own product descriptions. They are category labels, not a standard. Two products in one category can still differ, so read the actual product data sheet before you compare them.
A category name does not tell you whether a product fits your roof, panel profile, or snow load. Ask the manufacturer which category and model it recommends for your roof type, and ask for that recommendation in writing.
What Snow Guards Do and Do Not Do
Guards hold snow on the roof so it melts or releases slowly, but they do not melt snow or prevent snow load. Keep that difference in mind when you read any product claim.
Held snow still bears on the roof. The roof structure and its attachments must carry that retained load. That is a design question for a qualified professional, not a question a catalog page can answer.
What is not verified. This article did not verify any building code or ASCE 7 requirement for guards. It did not verify roof-pitch thresholds, guard spacing values beyond the calculator’s example, trade association guidance text, or whether guards may be fastened into purlins. No injury or damage statistics were verified either.
Treat those gaps as a reason to ask questions, not as permission to guess. A figure with no source behind it is not a verified rule, however confident it sounds.
A simple test helps when you read any guard claim. A statement about sliding snow describes the hazard. A statement about a number of guards describes a layout, and that layout still needs a check against your own roof.
When to Ask a Professional and What to Bring
Ask a qualified roofing or design professional before you choose a guard layout for a specific roof. The layout depends on facts about your building, so bring those facts to the meeting. These questions are a good place to start.
- What snow load is the roof designed to carry?
- Do the roof structure and attachments carry the snow that a guard holds back?
- Which guard category and model does the manufacturer recommend for this panel profile?
- Where will sliding snow land, and what sits below the eave, such as a lower roof or a walkway?
- Does the layout drawing show rows, spacing, and offset, and where do those figures come from?
Before the meeting, write down what you already know. Note where snow tends to collect, which walkways or entries sit under the roof edge, and where any penetrations are. The professional can then check those facts against the layout drawing.
Bring your roof plan, panel type, eave length, and any snow history you have for the site. For other roof and framing tools, browse the framing calculators hub.
Estimating Guard Count: A Worked Example
For a 40 ft eave with two staggered rows at 18 in spacing and 5% extra, the calculator’s example gives 56 guards. These are example figures, not a manufacturer recommendation. The spacing and the offset are planning assumptions.
Here is the arithmetic, so you can check it by hand.
- Convert spacing: 18 in is 1.5 ft.
- Count one full row: 40 ft / 1.5 ft = 26.67, rounded up to 27 guards.
- Count the offset row: the planning assumption is one fewer than a full row, so 27 – 1 = 26 guards.
- Add the rows: 27 + 26 = 53 guards.
- Add 5% extra: 53 x 1.05 = 55.65, rounded up to 56 guards.
The example uses one eave. A roof with several eaves, or a different spacing, needs its own count, so run each edge separately.
Your own eave, spacing, and layout will change the count. Check the layout with a professional before you order, and treat the 18 in spacing as an example, not a rule. For more reading, see the GeniesMag guides library.
Run your figures in the Snow Guard Calculator, then have a qualified professional confirm the layout.
FAQs About Snow Guards on Metal Roofs
Do I need snow guards on every metal roof?
No single rule covers every roof. The sources here describe the risk of sliding snow but give no verified rule for which roofs need guards. A qualified professional should judge your roof.
What is the main risk snow guards address?
Sliding snow and ice. A 1997 IIBEC paper says it can damage property, kill people, and overload lower roofs. Guards are attachments meant to stop snow from sliding off the roof.
Do snow guards take the weight of snow off the roof?
No. Guards hold snow so it melts or releases slowly. They do not prevent snow load, so the roof structure and its attachments must carry the snow that stays on.
How many snow guards does a 40 ft eave need?
The calculator’s example gives 56 guards for a 40 ft eave with two staggered rows, 18 in spacing and 5% extra. The spacing and offset are planning assumptions, not verified manufacturer values.
Are the 1997 snow guard guidelines still current?
Not verified as current. The 1997 IIBEC paper is old. It calls for improved design guidelines, standards, and performance criteria for snow guards on metal roofs. No newer standard was verified for this article.
Is the Rocky Mountain Snow Guards blog a neutral source?
No. It is a snow guard manufacturer’s blog, so read it as a seller’s view. This article does not use its injury or damage claims.
What should I ask a roofer before buying snow guards?
Ask what snow load the roof is designed to carry, whether the roof and attachments carry the retained snow, and which guard category the manufacturer recommends. Get the answers in writing.
Sources and Further Reading
References Used in This Article
This article covers need and risk and uses no verified code or load values. The layout for a specific roof must come from the guard manufacturer and a qualified roofing or design professional. Reviewed for accuracy by Prof. Dr. Khalil Mudassar, PhD. Last updated 2026-11-07.
Shakeel Muzaffar is the Founder and Editor-in-Chief, with over 15 years of experience in digital publishing and online tool development. He oversees editorial quality and formula verification to ensure accurate, practical, and easy-to-use calculators.