Struggling with the last inch of concrete on an egress window project?

That 1-inch bridge in the middle is exactly what's keeping the wall structurally sound enugh to resist a sledgehammer. You're fighting the compressive strength of the concrete, and a sledgehammer usually just bounces off a 10-inch wall because the mass absorbs all the energy before it reaches the center. Since you've allready cut it into four sections, the most effective move is to rent a **demolition hammer** like a Hilti TE 2000. It’ll cost way less than a new saw and it’ll turn that last inch of concrete into rubble in no time. You also need to check if you're hitting rebar. If there's horizontal steel running trough that middle inch, you can swing that sledge untill your arms fall off and nothing will happen. If you see any sparks or feel a metallic 'ring' when you hit it, you've found the culprit. You'll have to chip away enough concrete around the bar to get a reciprocating saw or an angle grinder in there with a metal-cutting blade to snap the steel.

If you're absolutely avoiding a rental, go back with your 4.5-inch saw and do more cuts to create a **checkerboard pattern**. Smaller chunks are much easier to break loose than those big four-foot sections. Use a heavy masonry chisel and a 3-lb hammer to work the relief cuts you've already made. But honestly, the rental breaker is the way to go. It saves you hours of vibrating your joints loose for the price of a decent dinner out.

I'm following this beacuse I'm looking at doing somthing similar next year. If you do manage to break those four big sections loose, how are you guys planning to actually move them out of the basement? A 10-inch slab that big has to be incredibly heavy. I’m worried about my back just thinking about it. Also, does using a demolition hammer create a massive dust cloud inside, or is it manageable if you keep the area wet? I've seen those hydraulic splitters online too, but those look pretty expensive for a one-time project.

Make sure you've got a plan for those blocks once they're loose. At 10 inches thick, concrete is about 150 lbs per cubic foot. If those sections are even two feet wide, you’re looking at several hundred pounds apiece. You'll need a heavy-duty dolly or some round PVC pipes to roll them out of the hole. If you won't rent a breaker, grab a hammer drill and 'stitch drill' the center of your cut lines. Drill a hole every two inches all the way through that bridge. It ruins the structural integrity enought that the sledgehammer acutally stands a chance. For the dust, just keep a shop vac nozzle right at the impact point.