Snow shovelling on roofs
The shovelling of snow must be planned and carried out in order to prevent snow and ice from falling from the roof and injuring people or damaging property, and preventing the roof, roof structure or its roof safety equipment being damaged due to overloading.
Always do a risk analysis concerning snow and ice falling and carry out the work of roof shovelling.
Create a roof shovelling plan and make sure that it is followed.
Snow shovelling zones
Avoid diagonal loads on the roof constructions and breakdowns by working with snow shovelling zones.
Establish the show shovelling zones in consultation with a craftsman. These are zones on the roof that must be shovelled in a suitable order for load reasons.
Use soft tools and leave a layer of snow
Do not use hard tools, such as axes, sledge hammers, steel shovels and plastic hammers that do not cause damage or leaks in the roofing material/waterproofing membrane.
Do not shovel away all the snow/ice, but rather leave about 100 mm on the roof.
Monitoring of snow loads
It is possible to monitor snow loads and begin roof shovelling in advance of any problems arising
Plan methods to measure snow depth and density (snow quantity in kg/m2). Install snow depth pennants to facilitate measuring.
Find out what the rated load on the roof and snow fence is.
For example, begin the shovelling (figures can differ depending on where in the country the roof is located):
- if on 1 March there is an amount of snow that corresponds to 70% of the rated load on the roof or snow fence etc.
Snow shovelling must be planned so that it can be done without risking injury to persons or damage to property outside of the roof..
Cordon off a sufficient amount of area below the roof shovelling
Always have one person, a guard, who makes sure that people below are warned when snow and ice are falling.
Personal fall protection
Snow shovelling must be planned so that it can be done without risking injury to persons falling on the roof or down from the roof.
Inspect well in advance of the snowy season that the roof and roof safety equipment are in good condition.
Make sure that there are ample signage and documentation at the access point as to what roof safety equipment is present on the roof, about particular hazards, for example, what is inside the rails surrounding weak areas etc.
Make sure that everyone present on the roof is trained in the use of personal fall protection, and check well in advance to see that the equipment is OK.
Set up a rescue plan for persons hanging off the roof and persons who are injured up on the roof.
Snow shovelling must be planned so that it can be done within an acceptable level of ergonomic problems.
As necessary, install so-called drop-down ladders in order to allow you to go down and up when working down at the roof foot on sloping roofs.
Requirements when shovelling snow on roofs
The roof may need to be shovelled of snow and ice for three basic reasons
- There is a risk of overload on the roof or of the equipment/devices on the roof
- There is a risk of water penetrating in under the roofing material/waterproofing membrane in connection with thawing.
- There is a risk of snow and ice falling down and injuring people or damaging property below the roof
Falling icicles can fly off far when they hit the ground. Place the barriers at a suitable distance away from the façade.
Use stable, dense and heavy barriers on the ground so that people cannot get through them. Have controlled openings at gates.
Snow fences can be used as anchors for personal fall protection. However, you should primarily use the walkway or the snow fence located above as the anchor point for personal fall protection equipment. Given the highest allowable amount of snow, a snow fence can be deformed somewhat during use. Try to relieve heavily loaded snow fences before subjecting them to the pressure of a person´s foot when using as a foot support.
Always be extra anchored when present at the outer corners or the roof, in order to reduce the risk of swinging.
The density (weight) of the snow can vary on roofs. Driven snow has a higher density than snow that has fallen straight down. The density increases the longer it lies, especially in late winter.