Describe Procedures of Insulating and Air/Vapour Sealing in Building Walls and Ceilings

Topic 4 – Describe Procedures of Insulating and Air/Vapour Sealing in Building Walls and Ceilings

Installing Insulation

Batts – Batted insulation is usually “friction fit” in the cavities they fill. The batts are cut slightly larger than the space between framing members and the resulting friction keeps the batts in place. Often the batts must be cut to irregular stud spaces. It is important to cut them to a width that does not require the batts to be overly compressed, as this reduces its R-value.

Roll Insulation – Roll insulation is often manufactured with an attached vapour barrier. The vapour barrier extends past the insulating material and these flaps are used to staple the batts in place.

Loose Fill Insulation – Loose fill insulation is typically blown in place with a machine but can also be placed manually and leveled with screeds. When using loose fill insulation in an attic space, insulation stops must be used and care must be taken ensure it is not filled above them and the insulation does not become compacted.

Rigid Insulation – When being used for exterior applications, rigid insulation must be allowed to breathe to allow any moisture that gets behind to dissipate out. Rigid insulation is attached in a number of ways. Often fasteners are used with large washer heads. Another method is to glue them in place, but special consideration needs to be taken to ensure the glue is compatible with the insulating material. If the insulation is to be used as an air barrier, an approved sealant must be used at the joints.

Spray Foam – In smaller applications, a one-part spray foam is often used. Typically, these are used to insulate and seal around doors and windows. In these applications, a low-expanding foam must be used to prevent the jambs from bowing in under pressure. For larger jobs, a two-part spray foam is often used which also acts as a vapour barrier.

Reflective Insulation – Usually stapled on the inside face of framing, an air space of 19 mm needs to be maintained behind it to allow if to be effective.

Health and Safety Precautions

There are several risks that are associated with different types of insulation. Batted and roll insulation releases small air-borne particles when agitated. These particles are both a respiratory and physical hazard which can irritate the lungs, nasal cavities, and any skin that is exposed to it. When handling or installing batted insulation, a dust mask, goggles, and long sleeved shirt is recommended.

Spray foams release hazardous gasses when applied. When applying spray foam a full face respirator is required as well as long sleeved shirts or coveralls to prevent skin contact from over spraying.