The "double blow'' method, with two open- ings, is commonly used for sidewalls. Some stud sections may require three or more open- ings because of construction features.

Openings should be made into the stud area for each 4-to-5 foot height. This is essential to ensure that the stud space is completely full. Never try to blow more than 4 feet down or 12 inches up. Blowing through a single opening in an 8-foot wall could leave some of the stud space with no insulation.

Many homes have eaves which are below the level of the wall plate. Frequently, access to stud spaces can be gained by removing the eave panels.

Plumb bob all stud cavities to determine the depth that can be filled through that opening. A plumb bob should be of sufficient size to readily reveal obstructions which could stop the flow of insulation.

Areas above and below windows and below firestops and bracing must be opened to determine exact location of obstructions and assure that the cavity is completely filled.

When removing the nozzle be sure to fill the space which it had occupied.

Some installers use the insert tube method, which consists of cutting one hole either at mid-height or near the top of each stud cavity. Insulation is blown into each cavity through a tube inserted to the bottom of the cavity and slowly withdrawn as the cavity is filled. The procedure is then repeated with the tube inserted in an upward direction.