Home insulation: How to re-insulate walls without tearing them down

One primary reason everyday people bear with drafty homes stems from construction costs. Old houses and those with failing exterior wall insulation seem to require costly demolition. The idea that drywall or select wood wall materials require removal and replacement often causes property owners to take a deep breath and think about something else.

The good news is homeowners enjoy increased access to quality insulation materials which may not require wall demolition.

What insulation materials are available?

The two leading materials that generally do not require wall removal are loose-fill cellulose and spray foam. These products task installers with drilling small holes — between ½ and two inches — in strategic locations. Specialized equipment then funnels the material into the exterior walls between the framing studs.

The idea is to pack the vacant spaces with material that deters air penetrations. These are differences to consider between loose cellulose and spray foam materials.

• Loose Cellulose: Properly installed and packed loose cellulose can deliver a higher R-value rating than a good deal of fiberglass batt products. This material may be best suited for older homes with little or no exterior wall insulation, which is largely because it may not push aside impediments such as outdated insulation behind walls. Another criticism of loose cellulose involves "settling." When not tightly packed, gaps can emerge at the top of exterior walls.
• Spray Foam: Injecting spray foam ranks among the viable solutions to reduce or eliminate drafts. This seemingly wet material floods the space between exterior wall studs and can form a firm barrier against air penetrations. Although spray foam also outpaces many fiberglass insulators, it does present a risk. Excessive spray foam funneled into walls can expand, resulting in cracks and bowed walls.

Not every handy DIY homeowner possesses the equipment or experience to effectively install insulation without removing walls, which is why it's essential to work with an experienced professional installer.

How to choose an exterior wall insulation material

Consult with an experienced insulation contractor that uses both materials. Their assessment of the house could prove invaluable in terms of selecting the best option. And, don't hesitate to field multiple quotes before writing a check because installation costs can differ significantly.