Wall Sawing for New Doors and Windows in Block and Poured Walls

A wall saw is a motor and large diamond blade that ride on a track bolted to the wall. The operator sets the track along the line and the saw makes pass after pass, going a bit deeper each time, until it cuts right through. Water runs to the blade the whole time to cool it and keep dust down.

Because the saw follows a fixed track, the cut is straight and consistent from top to bottom.

Poured walls are solid and often reinforced. The saw cuts concrete and rebar together. Once the outline is cut, the section is divided into blocks that can be lifted out safely, since a single full-height piece can weigh far more than a crew can handle. The edges come out smooth and square, ready for a lintel and a buck or frame.

Concrete block walls have hollow cores, some of which may be filled with grout and rebar. That changes the design more than the cutting. The engineer may call for filling cores beside the opening or adding a bond beam. The saw still gives clean edges, but the exposed cores need to be filled or capped as part of the finishing.

For a door or window, a clean cut pays off in a few ways:

New or enlarged openings in a foundation or exterior wall are structural changes, so in Mississauga you'll usually need a building permit with a lintel design. Temporary support may be needed during the cut. That part isn't optional, and a good contractor will ask to see the approved drawings before setting up.

When the last block comes out, you're left with four flat faces and square corners. The corners are usually finished with a core or handheld saw so the main cuts don't run past them, which keeps the wall around the opening from being weakened by overcuts. The opening is washed down, slurry is vacuumed up and the space is ready for the lintel, a pressure-treated buck or a steel frame. Compared with a broken-out opening, there's far less patching and parging to do before the door or window can go in.

It's also easier to check. The inspector and the installer can both measure the opening against the drawings and see straight away that it matches.

Wall saws aren't a weekend rental for most people. They're heavy, need water and power, and cutting a load-bearing wall wrong can have serious consequences. For anything like this, bring in a crew that does concrete cutting regularly and can coordinate with any structural work happening inside.

Whether your wall is poured or block, wall sawing gives you a clean, accurate opening with less damage around it. CoreCut Demolition Mississauga cuts door, window and walkout openings to the approved plan and hauls the concrete away. Get a free estimate if you're adding an opening.