Cutting Cement Board Siding

One way to eliminate cutting or at least keep it to a minimum would be to remove the entire piece above the window flash the window and then replace the siding.

Cutting cement board siding.

The cleanest way to cut fiber cement siding is by using siding shears. If any cutting needs to be done to allow for the added flashing than it can be done on the workbench with a pair of siding shears zero dust. I recommend the turboshear tsf1a fiber cement pnuematic if you re looking to buy a pneumatic siding shear. Use your eyeware and ear protection.

The advantage of using the circular saw is that you can cut more than one board at a time. Typically siding shears use air pressure to power them and they shear or cut the siding like a pair of scissors. Use a specialized blade used with the saw such as mikita hardiblade or dewalts filber cement blade. For a slow but virtually dustless way to cut siding use power.

These are specialized to reduce the dust caused from cutting these planks.