What R-Value is 2 Inches of Spray Foam Insulation?


R-Value measures how effectively insulation blocks heat transfer. If you are building or renovating an existing structure, installing spray foam insulation could be the ideal choice to protect against heat flow and preserve energy efficiency. Learn the best info about open cell vs closed cell foam.

Open-cell spray foam typically provides R-3.6 per inch insulation, while closed-cell options offer up to R-5.5. However, other factors need to be taken into account as well.

What is the R-Value of Spray Foam?

The R-value of spray foam insulation depends on its type and manufacturer; open-cell spray foam offers an R-value between R-3.6 to R-3.9 per inch, while closed-cell foam has an R-value beginning at R-5 per inch.

Note that spray foam insulation will gradually lose its R-value over time due to moisture permeability and air leakage through its microscopic pores. So, choosing top-quality foam from a reliable spray foam insulation contractor is always wise.

Some companies will claim that spray foam has a higher R-value than fiberglass. However, these claims can be misleading. When comparing products, the R-value of an entire wall must be taken into consideration, and fiberglass has a lower R-value but may be more accessible and perform well in most homes; also, remember that spray foam acts as an air barrier while fiberglass does not, meaning spray foam could potentially help improve energy efficiency by sealing air leaks in a home.

Ask about the Long Term Thermal Resistance rating of spray foam insulation products, as this will give a more in-depth picture of its performance over time.

What is the R-Value of Closed-Cell Spray Foam?

Spray foam insulation’s R-value may need to be clarified when compared with fiberglass or cellulose insulation, as its R-value tends to range between R-3.4 per inch and as much as R-5.7 per inch due to creating an air seal in your home and helping stop air This helps reduce drafts, increase comfort, and lower energy bills.

Closed-cell spray foam boasts a higher R-value due to its dense construction. Furthermore, moisture impermeable technology keeps moisture from seeping in and thus ensures it doesn’t absorb too much water into its structure – ultimately keeping its R-value unchanged over time.

Spray foam insulation has one of the highest R-values compared to other forms due to its ability to block heat transfer through convection and air movement rather than just resistive resistance alone. Furthermore, its high racking strength means it can bear significant pressure without crumbling.

When considering roof insulation, be sure to work with an experienced and knowledgeable home contractor who can ensure you obtain an R-value that suits your area and climate. Many factors affect this number, such as where you reside and local building codes.

What is the R-Value of Open-Cell Spray Foam?

Open-cell spray foam boasts an R-value between 3.5 to 3.6 per inch, producing a total R-13 in a 2×4 wall assembly. While this is better than fiberglass’s R-3 value, its performance depends on more than simply insulation thickness; air seal and tightness must also be considered when designing walls.

Open-cell spray foam should be considered vapor permeable, meaning moisture can move through it and alter its R-value, so incorporating a vapor retarder in applications where water might cause issues (attic ventilation, basements, or bathrooms) is essential.

Closed-cell spray foam doesn’t present this same issue because its bubbles are sealed, yielding an R-7 per inch when sprayed to its proper depth – still lower than fiberglass but better than other insulation types that could lose R-value over time due to moisture damage.

When comparing R-values across insulation types, it is critical to consider long-term thermal resistance (LTTR) tests. These measurements determine how effectively insulation resists heat flow over time rather than immediately upon installation. Spray foam typically maintains its R-value over the years, while other types, such as fiberglass and cellulose, will suffer moisture-induced R-value losses over time due to moisture damage.

What is the R-Value of EPS?

EPS insulation comprises 98% air and ultralight materials, making it the ideal choice for tight spaces where fibrous insulation would be difficult or costly to fill. Furthermore, its lower cost makes EPS an intelligent investment decision.

Spray foam insulation offers many advantages over fiberglass batts; unlike them, it won’t decompose and fall out of a wall cavity or become covered in dust over time – giving it much more extended longevity than other forms of insulation.

EPS insulation’s versatility lies in its moldability during production. This allows it to conform closely to whatever surface it’s covering, creating an extremely secure bond. This feature is particularly advantageous in building exteriors where water leakage or frost heave could otherwise occur.

The addition of poly facer can slightly boost EPS’ R-value; it adds a thin film coating on both sides that aids with both moisture resistance and durability. Geofoam products commonly incorporate this feature.

Before choosing a spray foam insulation product, it’s essential to inquire about its Long-Term Thermal Resistance (LTTR). This rating system indicates how well an insulation maintains its R-value over time; recently, the Connor Study [1] contributed evidence that XPS maintains its R-value under various cold climate conditions while EPS loses some R-value due to prolonged exposure to moisture.

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