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First, sealing is done to close any cracks that air or water vapor could seep through. Sealants eliminate drafts, provide thermal resistance, and keep out moisture, dust and insects. Sealing also helps in sound control. Some insulation companies will send a specialized crew in advance to apply sealants. Otherwise, this is the first task of the insulation installer. |
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Before sealants can be applied, the surfaces must be clean, dry, and free of oils. Remove any loose material with a putty knife or screwdriver, and sweep up dirt and debris. If the surfaces are damp, allow them to dry. Remove oil and grease with a solvent such as mineral spirits. |
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The sealants you will be using are generally of two types: caulking and urethane foam. Caulking is a paste-like material that cures to a solid state. It is applied with a caulking gun. |
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Any holes between conditioned and unconditioned spaces, or from floor to floor should be sealed. For example, drilled holes in studs that electrical wiring or plumbing runs through, or vent pipes through a ceiling. |
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Seams between walls and floors require sealing. As you apply the caulking, move at a slow, steady pace, forcing caulking into the gap. Smooth excess caulking with your fingertip or a putty knife before it dries. |
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The second type of sealant you may be using is urethane foam. Urethane foams are liquid materials that expand rapidly as they set to a semi-rigid state. The most common type is available in an aerosol can or larger canister. |
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To apply urethane foam, follow the directions on the label. Place the nozzle over one end of the gap, and then squeeze the trigger while dragging the nozzle across the gap. Because this material will expand, do not overfill the gap. |
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Window and door frames will require packing and chinking with scrap insulation, but applying caulk or foam may also be required. The method for applying foam varies with the material the windows and doors are framed with.
You should check the builder’s policy or with your supervisor before using foam around window frames. Sometimes expanding foam is not allowed, due to concerns about bowing aluminum or vinyl frames. Caulk will work well for these situations. |
