How To Air Seal Ceiling To Wall Connections In Attics

Consider swapping out or upgrading any duct work that is not insulated properly.

How to air seal ceiling to wall connections in attics.

Long piece from a batt of fiberglass insulation and place it at the bottom of a 13 gallon plastic garbage bag. Any ceiling vents need to be foamed and sealed where they meet the ceiling. Heated rooms built into attics often have open cavities in the floor framing under the walls. So we re not going to see the top plate of the framing.

After the drywall hangers get the ceiling done they come back and do the walls. Air sealing the attic perimeter. Fold the bag over and stuff it into the joist space under the wall. Plug all open joist spaces under insulated side walls.

It s usually the hardest place to air seal because the cramped space underneath the eaves where the roof rafters rest on the outer wall makes it hard to move your hands and head. Occasionally they ll put adhesive on the walls but usually they ll glue only the studs not the plates. The best way to shut these huge leaks off is to sheathe over them at the framing stage. In this video series we re going to show you some simple techniques and off the shelf materials that you can use to air seal up most all of the air leaks that you ll find in an average attic.

For a partition wall that runs parallel to the floor joist there s usually going to be some blocking in the ceiling. Ventilate the attic 1 sqft per 300 sqft of attic floor space balance at ridge and soffit areas. Mastic sealant paste is a slightly more effective and durable than hvac foil tape. Sealing the ceiling so the attic insulation can work.

Attics often have other huge openings that many builders don t see as air leaks. When the furnace or air conditioner is on check for air leaks around the duct connections with your hand a lit incense stick or a thing piece of toilet paper. If they d simply run a continuous bead of adhesive on the top plate too they d block the pathway for air to move between attic and walls. So simple a solution.

Air sealing the wall plate around the perimeter of your attic blocks air from escaping around the outer edges of your home. A common one occurs in the ceilings of single story attached garages where they bump up and connect to a larger attic space over the main house or to a two story wall. Air seal all penetrations and possible leakage paths. What we ll do is we ll seal that block to the drywall and that ll get almost all of the air leakage that s going to occur.

Loose connections should be clamped taped and caulked. Use mastic sealant or aluminum foil tape not duct tape to seal all of the duct connections.