Scaffolding in summer: heat, UV, thunderstorms and long standing times
Summer is peak season for scaffolding. Facades are painted, roofs recovered, windows replaced, and many scaffolds stand against the same wall from May to September. The weather seems ideal: dry, bright and long days. Yet the warm months bring their own risks, for the people on the scaffold, for material standing in the sun for weeks and for the scaffold as a whole, which is altered bit by bit over a long season.
Heat on the scaffold
On a sunny day a facade scaffold is noticeably hotter than the street below. The wall stores heat and radiates it back, steel decks and frames heat up, and air stagnates in front of a south-facing wall. Add sheeting or dense netting and even the breeze disappears. Working on the top lift of a south elevation means working in a heat trap.
Metal in direct sun can get hot enough to touch only briefly without gloves. That affects guard rails, ladders and frames during erection. A reflex jerk away from a hot rail is dangerous at height.
Employers generally have to cover heat in their risk assessment, under whatever rules apply in their country. Measures that work in practice:
- Shift working hours: start early and use the midday hours for shaded work or work on the ground.
- Follow the shade: west elevation in the morning, east elevation in the afternoon, where the sequence allows.
- Drinking water: enough of it, within easy reach, not left in a hot van.
- Breaks in the shade: regular, not only once someone feels dizzy.
- Gloves for erection and for gripping rails.
- Watch each other: headache, nausea and confusion are warning signs. An affected person comes down at once, accompanied rather than alone on the ladder.
Erection and dismantling are heavy work in summer. A steel frame weighs around 20 kg, a 3 m steel deck about the same. Passing several hundred parts up by hand at 32 °C (90 °F) exhausts a crew within hours, and mistakes rise with fatigue. A material hoist, shorter sections and an early start make the difference. If you are choosing material anyway, weight is worth considering: see aluminium or steel scaffolding.
UV: protecting skin and eyes
On a scaffold you are closer to the sun and often without any shade, and pale facades and fresh paint reflect even more light. Long, light clothing, a hat or helmet with neck protection, high-factor sunscreen and sunglasses belong to the summer kit. Where it suits the job, netting on the scaffold provides shade, which helps the workers and many coatings that dry too fast in direct sun. A net changes the wind load, though, and may only be fitted if the tie pattern is designed for it. How nets are used for paint work is covered in facade painting.
What the sun does to the material
Steel and aluminium are unaffected by sunshine. Other parts of a scaffold are less robust:
| Component | Effect of sun and heat | What to check |
|---|---|---|
| Nets and sheeting | UV makes the fabric brittle; tear strength drops | Tears, torn eyelets and brittle areas before reuse |
| Cable ties and single-use ties | Harden and snap under load | Fixings during long standing times; use UV-stable ties |
| Timber boards and decks | Dry out, split, warp | Longitudinal cracks, warping, loose end bands |
| Plastic parts, castor wheels | Can become brittle or deform | Wheels and brakes on mobile towers |
| Scaffold tags and signs | Fade and become illegible | Replace during long jobs |
Thermal expansion of steel hardly matters. A continuous 40 m run grows by about 12 mm with a 25 °C temperature rise, spread over many bays and joints that take it up easily. Far more important is a critical look at nets and sheeting after a season, before they go back on a facade. Timber boards deserve the same look.
Ground conditions in summer
Asphalt softens on hot days, and a base plate standing directly on it can slowly press in under load, especially on dark surfaces in full sun. Placing a wide sole board beneath each jack spreads the load, prevents this and protects driveways and footways at the same time.
Clay soils dry out and crack in summer. They often carry well, but not evenly. The danger comes when heavy rain falls after weeks of drought: water runs off the surface, washes material out from under sole boards or softens the ground suddenly. Check the base points after every downpour, particularly where downpipes discharge onto the ground or water runs off paving.
A scaffold on a lawn leaves the grass underneath soft and damp while the area around it dries out. Do not lift the sole boards to save the lawn. Any change to the base of a standing scaffold interferes with how loads are carried and belongs in the hands of whoever erected it. Plan wide boards from the start instead.
Summer thunderstorms
Summer storms often build out of a clear sky. Clouds tower in the afternoon, and within half an hour downbursts sweep across the site at speeds otherwise known from autumn gales. Preparation has to be faster than in winter, when storms are forecast days ahead.
- Check thunderstorm risk and warnings for your area every morning.
- On storm-risk days, take only as much material up as will be used by midday.
- Fix covering sheets for windows or material firmly, or remove them after use.
- At the first thunder, stop work and leave the scaffold.
- Afterwards check base points, cladding and decks before anyone goes up again.
Wind loads, cladding and storm preparation are covered in detail in wind and storms.
Long standing times: how defects creep in
A scaffold that has stood against a facade for four months is rarely the one handed over on day one. The plasterer removes a tie to work the area behind it. The painter removes a rail to pass up buckets. The window fitter pushes decks aside. Each change is quick, but not every one is put back.
So besides the daily visual check, fixed inspection dates make sense, plus an inspection after every alteration, after severe weather and after breaks, such as a two-week site shutdown in the holidays. For long jobs in Britain, the Work at Height Regulations 2005 set a maximum gap of 7 days between inspections; US scaffolds covered by OSHA rules (29 CFR 1926, Subpart L) are checked by a competent person before every shift. Where neither applies, your own country's rules set the rhythm. Points that typically change during a season:
- Are all ties shown on the tie plan present, and are the eye bolts still tight?
- Are guard rails and toe boards complete on every lift and at every end?
- Are all decks in place, with no foreign boards used as substitutes?
- Has insulation or render changed the gap to the wall?
- Are nets and sheeting still complete and taut?
- Is the tag at each access still legible and current?
Example: on an apartment block with an 18 m elevation and 13 m height, insulation, render and paint follow one another. The ideal wall gap changes with each trade: before insulation there must be room for the boards, afterwards the deck may be too far from the new surface. Plan inside brackets and a scheduled alteration rather than letting each trade adjust the scaffold. See scaffolding for external wall insulation.
Plants, insects, birds and empty houses
- Plants: hedges, climbers and branches grow into the scaffold, press on nets, hide defects and help intruders climb. Cut them back.
- Wasps: they nest in open tube ends, under sheeting and in bracket hollows. A sting in an awkward position on a ladder can cause a fall. Check tube ends and have nests removed by professionals.
- Nesting birds and bats: facades are habitats, especially under eaves. In many countries active nests and bat roosts are legally protected; contact the nature conservation authority, ideally before work begins.
- Holidays: many houses stand empty and evenings stay light. Remove the bottom ladder at night, lock the access and close reachable windows; see protecting scaffolding against theft.
Planning your own scaffold for the season? Ready-made scaffolding packages and a first estimate in the scaffolding calculator are a good starting point.