How Gaza Engineers Are Rebuilding With Rubble-Based Interlocking Blocks

Suleiman Abu Hassanin leads the Green Rock project in Gaza, where engineers are transforming destroyed building materials into Lego-like interlocking bricks for reconstruction. The workshop processes the massive debris left by conflict into standardized building blocks that can be assembled without mortar.

The project addresses two urgent problems at once. Two-thirds of Gaza's buildings have been damaged or destroyed, creating a debris field of roughly 42 million tonnes. At the same time, traditional construction materials remain scarce because the Israeli and Egyptian blockade has restricted the flow of supplies—particularly cement—for years.

How the Process Works

The Green Rock workshop crushes concrete, brick fragments, and other construction debris into blocks that lock together like Lego pieces. Because they interlock, these blocks don't need mortar to hold them in place, which speeds up assembly and uses less additional material. The interlocking design also distributes weight more evenly across the structure than traditional brick-and-mortar walls would.

This approach isn't entirely new in Gaza. In the past, Palestinians have rebuilt using smuggled cement smuggled through tunnels from Egypt, until Israel eased some restrictions in 2010. Local builders have repeatedly found ways to reuse rubble from previous conflicts. But the current scale is unprecedented.

The UN estimates it would take up to 15 years and half a billion dollars to clear around 40 million tons of rubble, with just the removal itself costing an estimated $18 million. Full reconstruction would require 1.5 million tons of new concrete. Even so, 71,000 structures have already been rebuilt according to the UN agency UNRWA.

A Parallel Technology: Mobile Block Factories

The Gaza initiative is happening alongside similar innovation elsewhere. Mobile Crisis Construction, a company founded in 2019, has developed portable block-making units that cost roughly $80,000 each and can produce up to 8,000 bricks per day. One week's output from these machines can provide enough blocks to build one school, one medical center, three large houses, or ten smaller joined houses.

Over three decades of covering technology and disaster response, I have observed this pattern repeatedly: when materials run short or time is critical, engineers and builders find practical alternatives using what's available. We saw this with prefab housing after the 2004 tsunami, and with modular building systems designed to withstand earthquakes. The same principle applies here.

The Technical Details

Processing war rubble into usable blocks requires sorting out metal, plastic, and other materials tangled in the debris. Workers in Gaza have been observed manually straightening old metal rods salvaged from destroyed buildings before using the remaining concrete to make new bricks. It is labor-intensive work.

The quality of blocks made from recycled rubble depends on how uniform the input material is and how the blocks are compressed. Blocks made from reclaimed concrete have already been reused to reinforce Gaza's beaches against erosion, which shows that recycled concrete can be structurally sound for load-bearing applications. Two teenage sisters from Gaza have been recognized for their work developing methods to turn rubble into reusable bricks, showing that the technical knowledge has spread beyond formal engineering circles.

Economics and What Comes Next

The blockade that restricts conventional materials has created a closed-loop economy where rubble becomes the main source of raw material for rebuilding. This constraint has spurred innovation in local manufacturing while also highlighting the broader challenge of resource scarcity in conflict zones.

In different parts of Gaza, communities are taking different approaches. Workers in Beit Lahiya in the northern Gaza Strip, for example, have been making clay bricks to rebuild a destroyed police station, based on what materials they have on hand locally.

The broader significance of what Gaza's engineers are doing extends beyond the immediate crisis. The technical innovations developed under extreme constraints—the processing methods, the interlocking designs, the local manufacturing capabilities—could be useful in other parts of the world where rapid construction using local materials is needed. Rather than treating rubble as waste to be hauled away at great expense, these projects treat it as raw material. This approach reduces disposal costs and transforms destruction into the foundation for rebuilding, which creates economic value from loss.

Whether these innovations spread and prove lasting will depend on whether the political situation stabilizes and material restrictions are eased. But the knowledge developed under constraint will outlast the immediate crisis.