|
|
Type of Material |
R-value per inch |
Other Characteristics |
|
Fiberglass, mineral wool |
|
Inexpensive. R-value eroded by air currents, compression. If flooded, must replace. Noncombustible. |
|
- batts, rolls (low-high density) |
2.9 - 4.3 |
Kraft paper good seasonal vapor retarder. Suitable for do-it-yourselfer. |
|
- loose fill, “Blown In Blanket” |
2.3 – 3.1 |
Good coverage (BIB for walls, roof). |
|
Cellulose |
|
Less air movement & erosion of R-value. Sound absorbing. Increases moisture buffer capacity of wall. Borate fire retardant, may deter insects, fungi. If flooded, must replace. |
|
- loose fill |
3.4 - 3.7 |
Good coverage. Can settle & lose R-value. |
|
- damp spray |
3.5 – 3.8 |
Good coverage, performance. Doesn’t settle. Let dry before installing drywall. |
|
Rigid foam boards |
|
As sheathing, good seasonal vapor retarder and reduces thermal bridging. If sealed, can provide exterior air barrier. Preferred for steel framing, masonry construction. Can withstand flooding. |
|
- expanded polystyrene (EPS, “beadboard”) |
4.0 |
Semi-permeable without skin. Least expesive type of rigid foam. Available foil-faced (for radiant barrier). |
|
- extruded polystyrene (XPS) |
5.0 |
Stronger than others. Low permeability; impermeable with skin. |
|
- polyisocyanurate (ISO board) |
5.6 – 6.5 |
More R-value in less space. Typcially foil-faced; provides vapor barrier & radiant barrier (good for brick veneer). |
|
Spray foam |
|
Excellent air barrier, seals penetrations. Uniquely well suited for insulating unvented attics, band joists, gaps in thermal/air barrier envelopes. |
|
- closed cell, high density (urethanes) |
5.6 – 6.3 |
New types have no CFCs. Cures to semi-rigid, adds strength, floodproof. Semi-permeable. Can withstand flooding. |
|
- open cell, low density (polyicynene) |
3.6 |
Stays flexible. Permeable. Can absorb water but dry quickly. |
|
Radiant barriers |
varies with use |
Requires min. ¾” min. air space. Most effective under roof deck. Other insulation still needed; blocks only radiant heat, not conduction. |
|
Autoclaved aerated concrete (AAC) |
1.1 – 1.4 |
Provides structure & thermal mass benefit. Noncombustible. |