Hybrid Foam Wall Insulation

Hybrid spray foam insulation systems were developed as a way to help home owners enjoy the benefits of polyurethane insulation while allowing developers to include such a system at a greatly reduced cost. This article effectively describes multiple facets of Hybrid spray foam insulation systems including consumer demand, advantages, cost concerns, installation, flexibility, air quality, and business entry costs.

Consumer Demand For Quality Insulation

A recent survey performed by the National Association of Home Builders (NAHB) illustrated a few recent trends among home buyers. With the extreme rising costs of energy prices, home buyers have become acutely aware of the need for a properly insulated home.

Generally, people accept that by spending more upfront on quality insulation, they can avoid substantial energy costs in the long run, effectively saving money, and improving their quality of living. Although traditional fiberglass batt insulation provides R-Value, it completely falls to prevent air infiltration.

Spray Foam Advantages

More people are becoming aware that polyurethane spray foam insulation both insulates and prevents air infiltration. In addition to this, in laboratory tests, spray polyurethane foam is proven to greatly outperform fiberglass in extreme weather conditions.

In fact, SPF foam, in extreme weather, outperforms fiberglass by more than 50% (in the test, 4.5 inches of medium density spf foam outperformed 14 inches of fiberglass; in other words, 30 R-Value in Foam, outperformed 50 R-Value in fiberglass). For details on the laboratory testing see our article: Spray Foam Outperforms Fiberglass in Performance Test

Hybrid Foam Insulation: The Answer to Spray Foam Cost Concerns

Contractors are aware that home owners want to save money on energy costs, but raw materials costs have been rising during the past few years, and with the housing market crash (falling prices, rising costs) developers are feeling the pinch.

Pure closed cell spray foam insulation systems are substantially more expensive than traditional fiberglass batts (medium or higher density is also higher cost). So, although people are aware of the performance benefits of sprayed polyurethane foam, including long term cost savings, the upfront cost of completely filling rafter bays, wall cavities, etc remains prohibitive.

This is based on a few reasons: 1-spray foam equipment is much more expensive and difficult to maintain than traditional insulation related equipment, 2-spray foam requires much more training for employees (higher hourly business costs), and 3-spray foam materials cost contractors substantially more than traditional insulation. In other words, equipment, labor, and materials all cost substantially more with spray foam.

Hybrid Foam Wall Insulation: Installation

The innovation of hybrid foam insulation is known as “flash and batt”. The “flash” consists of spraying closed cell foam to a depth of just 1” to 2”. The “batt” then involves filling the rest of the space or cavity with a fiberglass batt The fiberglass provides high R-value, while the foam prevents air leakage and moisture infiltration. The spray foam allows the fiberglass to perform well beyond it’s normal capacity. The end result is a system, which is much cheaper to produce than a pure SPF sprayed foam system, but still greatly outperforms a traditional blown or batt fiberglass system. Due to the reasonable costs coupled with great performance, the hybrid system is quickly becoming the mainstream standard for insulation.

If you’re considering a hybrid foam wall insulation system, it’s important to choose a closed cell foam system. Closed cell foam rises more slowly than open cell foam, which makes it easier to control the thickness and spray it more smoothly. This leaves proper space for the fiberglass; if the fiberglass is crushed or has insufficient space, it will not perform at the highest level.

As mentioned above, closed cell foam is moisture resistant, and seals air leakage too. Open cell foam has low R-value, is more prone to absorb water, and allow air and moisture movement. Open cell foam is also much lower density than closed cell foam, which means lower R-values. Hence, with hybrid foam wall insulation wall systems, be sure that your contractor will “flash” with closed cell foam vs open cell foam due to higher R-values, better air and moisture trapping, and due to thickness control, which maximizes the performance of the fiberglass batts.

Low Pressure vs High Pressure Installation Equipment

Keep in mind there are two primary types of installation spray foam equipment: high pressure and low pressure. For pure spray foam insulation installs, a high pressure system is by far superior to a low pressure system (output capacity, foam quality, etc). However, a low pressure system is sufficient for installing a hybrid foam insulation system.

A low pressure system allows more thickness control; if the foam is sprayed evenly, and smooth, the fiberglass batt will perform at its maximum capacity. A high pressure system makes it harder for an applicator to keep things even and smooth, so it’s easier to accidentally make an area too thick. This can increase materials costs, due to the high expense of sprayed foam. Aside from the materials costs, too much foam may force the installers to crush the fiberglass batts to fit them in the wall cavity or rafter space, which will hurt the performance of the fiberglass batts.

Keep in mind, companies using high pressure systems are often more experienced, and more skilled with spray foam application (high pressure systems are expensive and represent a larger investment). So despite the increased difficulty of spraying with high pressure (vs low pressure), an experienced applicator can still produce high quality results that will maximize the performance of the fiberglass batts (in a hybrid application). More expensive high pressure systems also produce higher quality, higher density foam, increasing R-values, and performance, and they allow an applicator to complete a job more quickly, which means reduced labor hours. And, as mentioned, a high pressure system is much more effective for installing a more expensive pure spray foam insulation system.

Flexibility: Improving Performance Even Further

Contractors using hybrid foam wall insulation can use spray foam without any fiberglass as needed in hard to reach areas, or poorly designed areas that do not allow space for fiberglass batts. Contractors can spot foam these akward spaces as needed, while using only a thin 1”-2” layer of foam on standard exterior walls and rafters.

Indoor Air Quality

Indoor Air quality becomes is an important concern with a pure or hybrid spray foam insulation system. Spray foam completely traps air and moisture, preventing air from flowing in or out of a home. While this is wonderful for improving insulation, this can eventually result in stale unhealthy air if a home is poorly ventilated. It is highly recommended that a home owner or contractor installs some type of air filtration or ventilation system in a home with spray foam insulation. This way, insulation can be maximized without compromising air quality.

Spray Foam Insulation: Business Entry Costs

Entry costs are substantially lower for businesses using low pressure spray foam equipment. A 150 foot low pressure system generally costs less than $25,000 (this tends to be a small system which can be attached to a truck or trailer). A brand new high pressure spray foam system requires a mobile foam rig trailer, and total costs can easily rise north of $100,000. A low pressure system is also easier to maintain and may save as much as $10,000 in annual maintenance costs (vs a high pressure system). However, low pressure systems do have limitations and they are not the best option for installing pure spray foam installation systems. Low pressure systems may make the most sense for a new or small businesses, while medium, large, or well established businesses may benefit more from a high pressure spray foam system.

I had not heard of hybrid foam insulation systems until I read this article. It makes sense though. Why not combine the best of both worlds.. low cost + high performance & get a great product that will really insulate well. I'm glad to see closed cell spray foam insulation start going mainstream. It's a great product and those involved in the industry have known about it for many years. However the public has been unable to reap the benefits simply because I think most people are not informed about the great benefits of spray foam insulation. I am glad to see that those who are unable to afford pure spray foam insulate have an option now.