attached bolted durability durable firm frame gray grey roofing see-through steel steel roofing frame strength support trusses angles background backgrounds blue sky colors colours contrast orange roofing angles roofs rooftiles rooves shapes sky. blue textures tiles coated imitation rough sheets texture tiled appearance church cross red roofing tiles roof wall white covered mossy old red tile building lines moss rows architecture buildings house sky blow housetop slate brick shingle shingles top urban close-up grains granules grit pebbles