above angles appearance building capping cover covered covering edge exhaust-pipes exterior external grooved grooves height high roof roof-area roof-capping roof-whirlybird roofing rooftop shapes sky sunlight sunshine textures tiles tiling turbine-ventilator vent ventilation ventilation-exhaust-pipes ventilation-system ventilator vents whirlybird whirlybirds wind-turbine cleaning danger dangers ear protection high-pressure improvement maintenance pressure pressure-cleaning renovating renovation repairs restoration restoring risks risky safety skies spray tools tough water wet work workman architectural construction dark dirty discolored discoloured elements gap hole lines missing old out of alignment perspectives protection protective rows Somber sombre surface surfaces uneven