In this final installment about insulation we’ll take a look at the family of rigid boardstock materials. Unlike fiberous or spray-foam insulation that is installed in wall or ceiling cavities between the studs, rafters, or joists, boardstock insulation is applied either on the interior or exterior surface, spanning across the framing.

三种最常见的刚性板材绝缘材料是塑料泡沫：挤出聚苯乙烯，膨胀的聚苯乙烯和多异氰脲酸酯。挤出的聚苯乙烯（XPS），包括熟悉的轻蓝色聚苯乙烯泡沫塑料和Owens Corning的粉红色泡沫，是这三个最耐湿度，通常用于低于级，以绝缘基础壁的外部和基底板块。XPS提供每英寸R-5的绝缘值。Unfortunately, XPS (in this country) is still made with ozone-depleting HCFC blowing agents, which manufacturers are required to eliminate by 2010. Manufacturers of blowing agents, refrigerants, and other compounds have made great progress in eliminating substances that destroy the Earth’s protective ozone layer in the stratosphere since the hole in the ozone layer above Antarctica was discovered in the 1980s. XPS is the only insulation material still made with ozone-depleting blowing agents.

膨胀的聚苯乙烯（EPS），也称为泳板，由小公司局部制造，而不是XPS，可以在更广泛的尺寸，厚度和密度范围内购买。最常见的EPS，密度为每立方英尺的密度约为1磅，低于级别，但它可以在较高的密度下订购，这些应用在这种应用中更好。对于低于地使用，我建议每立方英尺至少1.5磅。两磅EPS更好，性能更接近XPS。最常见的低密度EPS是每英寸约R-4的含量。它用戊烷制造为发泡剂，不会损害臭氧。EPS是用于生产结构绝缘板的最常见的绝缘材料，例如由冬季面板公司和FIARD面板局部制作的那些。

Polyisocyanurate is the highest-insulating boardstock option, providing R-6.0 to R-6.5 per inch. A special low-conductivity gas fills cells in the insulation, and foil facing slows down the loss of this gas or entry of air—a process that, unfortunately, reduces the R-value somewhat over time. This gas fill or “blowing agent” used to be an ozone-depleting compound, but manufacturers have shifted to ozone-safe blowing agents, usually pentane.

Polyisocyanurate is most commonly used for roofs and walls, but almost never below ground because it can absorb moisture.

In addition to these three rigid-foam boardstock materials, there are also rigid fiberglass and mineral wool boardstock insulation products. These are excellent in the right applications, but they are usually only available for commercial construction; they are not carried by most building supply centers serving residential builders and homeowners.

No matter what the type, boardstock insulation opens up some great opportunities for creating highly insulated—or superinsulated—walls. With new construction, I have long been a proponent of going well beyond a typical 2×6 wall insulated with cavity-fill fiberglass or cellulose. I believe that a reasonable R-value target for walls is R-35, and if I were building a new house I’d probably aim even higher. The easiest way to achieve such a high insulation level with wood-frame construction is a 2×6 wall with cellulose cavity-fill insulation and then an exterior layer of 3” of polyisocyanurate boardstock. However, that wall system, providing about R-35, will entail some extra effort with detailing:

首先，较厚的墙壁将需要覆盖窗户和门周围。其次，您可能需要将两层板式绝缘（1“层和2层）相结合，以实现推荐的三英寸。第三，除了板钢绝缘外，还需要提供架子强度（以握住墙壁方形），所以还需要置入金属支撑或胶合板或OSB护套。

Lastly, to install siding, you’ll need strapping with extra-long screws to secure it to the wall studs. (An added benefit is that the air space behind the siding that this strapping creates—called a rainscreen detail—improves the life of the siding and reduces the frequency of repainting.)

通过在外部提供这种厚的箔面板层绝缘层，在2×6壁腔内几乎没有水分冷凝的可能性;腔填充纤维素绝缘将被完全保护。在本栏中的未来几个月将覆盖在结构墙外悬挂在结构墙外悬挂的SuperInged Houses的其他方法，包括SIP施工，双螺柱墙和特殊的非结构壁桁架。