Dense Packing a wall, ceiling or floor provide a superior insulation performance. The density helps eliminate leaks and better controls the loss of heat and cool.
Dense Packing Walls
Dense packing existing walls is a traditional, time-proven technique to increasing thermal performance. Retrofitting does not always involve removing the interior drywall/plaster. Drilling a hole in the exterior or interior and sending a tube into the cavity is the best way to minimize retrofit costs.
In recent years, it has become popular to dense pack walls in new construction. Before the drywall is placed, insulation contractors have an option to pack the exposed cavities by using a material like InsulWeb. This material is applied to the wall by stapling it every inch. This provides a strong barrier to receive the dense packing of 3.5 psi. The contractor has a very good view of the cavity and how it is filled. Some manufacturers have created certifications to install their products. We do not advocate one material company over another. However, there are no necessary qualifications necessary to install cellulose or fiberglass in this manner.
Dense Packing Ceilings
This is a difficult area. Ceilings must be ventilated. If you are not able to ventilate a ceiling area, then do not dense pack it. It will create mold and rot the roof. If the roof is covered with foam, then dense packing is fine since the foam creates a thermal barrier where moisture cannot penetrate.
Dense Packing Floors
Contractors want insulation in floors for one of two reasons: 1) The floor is exposed above non-air conditioned space. 2) The floor is between two living spaces and there is a desire to eliminate sound.
Floor above non-air conditioned space
- If the floor is above a crawl space, think twice about dense packing the floor. Consider insulating the stem walls with a fire-rated vinyl covered insulation material. The ground temperature will seldom rise above 54 degrees in a properly insulated crawl space.
- If the floor is exposed (e.g., a house on stilts or cantilevered), then dense packing is an excellent way to insulate a floor system.
Sound control between living spaces
Before you insulate between living spaces to control sound, keep the following in mind:
- When you insulate a floor, you prevent the upper floor from radiant heat. This means each floor must have its own zone and control temperature.
- Dense packing with cellulose and rockwool are great ways to control sound.
- Watch out for light fixtures that protrude into the floor system. These must be treated in the same way a light in the attic is treated.