BASC Search

Air Sealed, Insulated Basements

Guide

Guide describing how to insulate a basement to improve the overall thermal performance of the building and provide more dry, usable conditioned space for home occupants and HVAC equipment.

Air seal the attic access panel with weatherstripping.

Image

Air-seal the attic kneewall door opening with weatherstripping.

Image

Air seal attic access panels and drop-down stairs to minimize air leakage.

Image

Right – The knee wall is properly insulated and air sealed.

Image

Air seal and insulate drawer and closet boxes in attic kneewalls

Image

Right – The backing on this knee wall was air sealed prior to insulation.

Image

Air seal the attic access pull-down stairs opening with weatherstripping.

Image

Wrong – The backing on this knee wall was not air sealed prior to adding insulation.

Image

Wrong – The batt insulation on this knee wall is not properly supported and there is no air sealed rigid backing to provide a solid air barrier.

Image

Spray foam insulation is installed in open wall cavities to air seal and insulate

Image

Wrong – If the insulated sheathing will serve as an air barrier and drainage plane, any cuts and seams must be taped or sealed.

Image

Infrared thermography during depressurization testing reveals air leakage at corner of spray foam-insulated room where wood-to-wood seams in framing were not air sealed

Image

Right-- IR photo shows how effectively spray foam insulated/air sealed attic kneewall and the floor cavities under kneewall

Image

Rigid insulation and air-sealing can be used to thermally isolate garages from interior occupied space in multifamily row houses/townhouses.

Image

Right – Structural insulated sheathing can provide racking strength (lateral load resistance), and serve as an air barrier and thermal barrier if installed according to manufacturer’s specifications with taped, sealed seams

Image

Why Seal and Insulate?

Reference

Introductory guide to air sealing the envelope of a home to reduce wasted energy and save on energy costs.

Air leaking through the home's envelope wastes a lot of energy and increases energy costs.

Image

Technology Solutions Case Study: Complete and Fully Aligned Air Barrier

Case Study

Case study describing the elimination of excessive humidity in the attic of a multi-floor, single-family home that was causing condensation and water damage along the roof and eaves.

Right – This attic knee wall and the floor joist cavity openings beneath it are being sealed and insulated with spray foam.

Image

The attic kneewall and the open floor cavities under kneewall are both sealed and insulated in one step with spray foam insulation

Image

This kneewall has no top plate and the resulting gap provides a wide-open pathway for air and vapor to travel between the living space and the attic

Image

Right - New flashing has been installed to complete the air and water control layers at the window openings of this wall retrofit that includes insulating the wall cavities with spray foam

Image

Certified Insulated Siding: Quality, Comfort and Energy Performance

Presentation

This presentation will help you define insulated siding, understand R-value testing of insulated siding, describe proper installation of insulated siding, comply with energy codes and understand building energy performance program and software recognition.

Air Sealed, Insulated Basements

Air seal the attic access panel with weatherstripping.

Air-seal the attic kneewall door opening with weatherstripping.

Air seal attic access panels and drop-down stairs to minimize air leakage.

Right – The knee wall is properly insulated and air sealed.

Air seal and insulate drawer and closet boxes in attic kneewalls

Right – The backing on this knee wall was air sealed prior to insulation.

Air seal the attic access pull-down stairs opening with weatherstripping.

Wrong – The backing on this knee wall was not air sealed prior to adding insulation.

Wrong – The batt insulation on this knee wall is not properly supported and there is no air sealed rigid backing to provide a solid air barrier.

Spray foam insulation is installed in open wall cavities to air seal and insulate

Wrong – If the insulated sheathing will serve as an air barrier and drainage plane, any cuts and seams must be taped or sealed.

Infrared thermography during depressurization testing reveals air leakage at corner of spray foam-insulated room where wood-to-wood seams in framing were not air sealed

Right-- IR photo shows how effectively spray foam insulated/air sealed attic kneewall and the floor cavities under kneewall

Rigid insulation and air-sealing can be used to thermally isolate garages from interior occupied space in multifamily row houses/townhouses.

Right – Structural insulated sheathing can provide racking strength (lateral load resistance), and serve as an air barrier and thermal barrier if installed according to manufacturer’s specifications with taped, sealed seams

Why Seal and Insulate?

Air leaking through the home's envelope wastes a lot of energy and increases energy costs.

Technology Solutions Case Study: Complete and Fully Aligned Air Barrier

Right – This attic knee wall and the floor joist cavity openings beneath it are being sealed and insulated with spray foam.

The attic kneewall and the open floor cavities under kneewall are both sealed and insulated in one step with spray foam insulation

This kneewall has no top plate and the resulting gap provides a wide-open pathway for air and vapor to travel between the living space and the attic

Right - New flashing has been installed to complete the air and water control layers at the window openings of this wall retrofit that includes insulating the wall cavities with spray foam

Certified Insulated Siding: Quality, Comfort and Energy Performance

Attic Knee Walls

Mastic Home Exteriors Installation Guide

Blown Insulation for Existing Vented Attic

Batt Insulation for Existing Vented Attics

Home Performance Assessment

Skylight Shaft Walls