Construction dust: Cutting roofing tiles

Using cut-off saws on roofing tiles can produce very high levels of silica containing dust. Effective control is necessary because this work is high risk. This page tells you how to control the risk and why.  You also need to be aware of the general information on construction dust.

What you must do

Follow the Assess, Control and Review model. Pay particular attention to the following things:

Assess

Identify and assess: Using cut-off saws on roofing tiles can produce very high levels of silica containing dust. Anyone breathing in this dust cloud will be affected. Those using or very close to the cut-off saw will be particularly at risk. Follow the control steps below.

Control

Prevent: Think about limiting the amount of dust you could make before work starts by:

• allowing for ½ or 1½ size tiles during design. Also consider using dry valleys
• natural slate and fibre cement slates do not need cutting with power tools. Use the correct hammers and cutters instead. Use these also to cut concrete and clay tiles where possible – eg at the rake of the hip where the two faces meet
• correctly set out the tiles so that those immediately below the ridge do not need cutting
• plan for using a cut-off saw. Space is needed for a dedicated cutting area(s) on the scaffolding. Ensure a supply of spare water is in easy reach. Think about controlling the slurry and limiting the number of people near the work.

Control: Even if you minimise some of the dust this way, you may still need to use a cut-off saw. Control the risk by:

• Equipment – use a hand-held cut-off saw with a water suppression attachment. Connect this to a pressurised water container. Wear respiratory protective equipment (RPE) with an assigned protection factor of 20 (eg FFP3 disposable mask or half mask with a P3 filter). Fit testing is needed for tight fitting masks. Use water resistant markers if needed.
• Cutting area – carry out cutting work in an area set aside on the scaffolding for this. It is vital to protect the scaffold boards from being cut while doing this. Use a suitable piece of sacrificial material between the tile and scaffold board.
• Verge tiles – these will need cutting to a standard size. Mark this on the tiles needed and cut on the set aside area using the equipment above.
• Ridge tiles – only a small number should need cutting. Again, mark and cut on the cutting area using the equipment above.
• Hip and associated tiles – use hand tools where possible. Otherwise size each tile on the roof and cut on the cutting area using the equipment above.
• Valley tiles – methods will vary depending on roof pitch and fixing specification. In general, tiles should be set back from the valley and marked using the covering width of one or more tiles. This establishes the cutting line.  Take these down and cut on the cutting area using the equipment above. A certain number of roof tiles will need to be re-laid to ensure the fixing specification is followed. Minimise this by staggering the tiles or cutting them individually instead of in sets.

Review

• Supervise: Ensure controls are properly used and RPE is worn correctly. Anyone using tight fitting masks also needs to be clean-shaven and face-fit tested.
• Maintain: Check water jets on the saw are clean and water containers well maintained. Replace seals and worn cutting discs when needed. Properly store, and maintain non-disposable RPE. Change filters as recommended by the supplier.
• Monitor: You may need a health surveillance programme unless you are sure exposure to silica dust is well below the recommended exposure limit.

What you should know

This work involves a number of quick cuts done outside. That does not mean it is low risk. Dry cutting quickly produces very high peak exposure levels of silica dust. Breathing this dust causes serious lung diseases like cancer and silicosis. These diseases cause permanent disability and early death. Use the controls above every time you do this work to limit the amount of dust you breathe in. This will stop any damage to the lungs building up over time.