Block work walls, otherwise known as breeze blocks, are a cheap concrete masonry unit. This type of cinder block is made from coal ashes. The blocks are good for garden walls, garages, and patio screens.
For commercial building construction, they are used for stairwells, balcony screenings, and curtain wall sun-shading to large windows. The blocks are popular in hot climates as they allow a breeze through, which is how they got their name.