1.   A half-dozen anonymous workers scout ahead to check possible hive locations in hollow trees or wall cavities.

2.   Also, if you expose such pipes, insulate them before installing insulation in the wall cavity.

3.   Another way to protect pipes in a wall cavity is to put a vent in the wall where the pipes go up.

4.   As the toggle passes through the drywall, a pivot bar opens out in the wall cavity.

5.   Bees rarely enter houses and even more rarely build hives in wall cavities, although it has happened.

6.   Blown-in insulation without a vapor barrier does not cause decay problems, nor does it settle in the wall cavities, when done right.

7.   Determining that mold exists in interior wall cavities, however, requires more work.

8.   Eventually the box will break free and fall back into the wall cavity.

9.   Generally, Ms. Benedict said, cellulose insulation is injected into the wall cavity through holes cut in the spaces between the studs.

10.   If the wall cavity is wet, it must be dried out before proceeding.