Quick Answer

Cut a door opening in a concrete wall with a wall saw (track saw) using a 500–800mm laser-welded blade, cutting the perimeter in 20–30mm increments until cut through. Support the wall above the opening with a lintel or props before cutting, and handle rebar separately with metal cutting discs or a rebar blade.

Before You Cut

• Engineer approval — load-bearing walls need a structural plan and lintel design.
• Props and lintel — install temporary props and prepare the lintel to carry the load above.
• Locate services — scan the wall for conduit, pipe and rebar.
• Mark the opening — door openings are typically 900x2100mm or as designed.

Cutting the Opening

• Wall saw — a track-mounted saw with a 500–800mm blade cuts through 200–300mm walls cleanly.
• Incremental passes — 20–30mm per pass; full-depth plunge in one go overheats the blade and risks kickback.
• Cut the top first — then the sides, then the bottom (or leave the bottom for last with core holes).
• Rebar — cut steel with a metal disc or rebar blade once the concrete is out of the way.

A Laser Welded Concrete Saw Blade in wall saw sizes handles the concrete; keep a HF-welded blade for lighter block walls.

Safety and Support

• Never cut a load-bearing wall without temporary shoring.
• Cut wet to control silica dust, or use a vacuum system.
• Remove the cut block with a breaker, not by prying against the blade.
• Install the lintel before removing the full opening block.

Frequently Asked Questions

Q: Can I cut a door opening with an angle grinder?

Only for thin non-load-bearing walls (under 100mm) and short sections. For full wall openings, use a wall saw — grinder cuts wander and overheat.

Q: What size blade do I need for a 200mm wall?

A 500mm+ blade is needed to reach through a 200mm wall with incremental passes. Smaller blades require cutting from both sides.

Q: Do I need a lintel for every door opening?

In load-bearing walls, yes — the opening removes support that must be replaced by a lintel. Non-load-bearing partitions may only need edge support. Confirm with an engineer.

Conclusion

Door openings in concrete walls are a wall-saw job: props and lintel first, incremental perimeter cuts, rebar handled separately, then the block removed. Plan the support before the first cut. JOY TECH supplies laser-welded blades for wall saws up to 800mm.