Bush hammered vs flamed: what is different
Bush hammered is machine-pounded: even dimples, a regular pattern. Flamed is burnt: random texture, finer relief. Flamed grips slightly better, bush hammered feels more even underfoot. Steps usually take bush hammered; plazas take either.
How do the two processes differ?
Bush hammering drives a row of hammer heads across the slab at speed, each impact with the same force, leaving an even field of dimples. Flaming passes a flame over the surface and lets the crystals fracture at random, leaving irregular roughness. One is mechanical impact, the other thermal shock, and the hand feel is entirely different.
How do they look?
Bush hammered has uniform granule size and reflects light evenly, reading like coarse sandpaper from a distance. Flamed varies in depth and granule size, looks more natural and coarser. On the same block, flamed is usually half a step lighter than bush hammered.
Which grips better?
Flamed, marginally: the relief is finer and the edges sharper. Both are far better than polished. For ramps and step nosings either works; what matters more is getting the drainage fall right, because standing water is more dangerous than surface texture.
Which holds dirt longer?
Bush hammered has regular dimples that trap mud, most visibly on dark stone. Flamed relief is irregular, so washing carries debris off more readily. Both need periodic pressure washing; the difference is how often.
Do the colours differ?
Yes. From the same block, flamed is lighter and more matte than bush hammered. When both are used on one facade, make a physical sample first. Do not judge from a photograph: the direction of the colour shift in print often does not match the real thing.