under house insulation for a raised house-The Secret to Lowering Your Energy Bills

When it comes to home insulation, the unique challenges of a raised house can't be overlooked. Providing adequate under house insulation is essential for energy efficiency, indoor air quality, and overall comfort in your living space.

In this insightful blog post, we'll delve into the ins and outs of under house insulation for raised houses—covering types of materials, installation techniques, and factors to consider when making key decisions.

Understanding Under House Insulation

Under house insulation for a raised house is designed to create a thermal barrier that helps maintain consistent indoor temperatures and reduces heat exchange between the home interior and the ground or air beneath it.

Raised houses have their floors elevated above the ground level, making them more susceptible to temperature fluctuations due to direct contact with outdoor conditions.

There are several types of insulation materials suitable for under floor installations, such as XPS foam boards, spray foam, fiberglass batts, cellulose batts with open cell sprayed cellulose or closed cell sprayed foam.

Each material has its unique properties in terms of thermal resistance (R-value), moisture protection, installation process, and budget considerations. For instance, rigid XPS foamboards offer excellent insulating performance while providing minimal environmental impact.

In hot and humid climates where excessive moisture poses challenges for many types of insulation materials due to potential mold growth or reduced effectiveness over time; it's essential to choose products suited specifically for this environment along with implementing proper vapor barriers to avoid any issues down the line.

Benefits Of Under House Insulation For A Raised House

Insulating under a raised house not only increases energy efficiency but also improves indoor air quality, enhances comfort, reduces moisture and mold growth, and increases durability.

Increased Energy Efficiency

One of the primary benefits of under house insulation for a raised house is increased energy efficiency. Without proper insulation, an uncomfortable amount of heat or cold can seep through your floorboards, causing your HVAC system to work overtime and driving up your energy bills.

Insulation works by acting as a thermal barrier between the inside and outside of your home, preventing unwanted air transfer from taking place. With enough insulation in place, you'll be able to keep your indoor temperature stable without having to run your heating or cooling systems excessively.

This not only saves you money but also reduces the overall carbon footprint in line with eco-friendly standards.

Improved Indoor Air Quality

Insulating the floor of a raised house can significantly improve indoor air quality. With proper insulation, there is less chance of allergens, dust mites, and pollutants entering your home.

In addition, good insulation helps prevent moisture from entering your home by keeping out damp air and reducing the risk of mold growth. This means that the air in your home will be cleaner and healthier to breathe.

Using materials like closed-cell sprayed foam or rigid XPS foamboards as thermal barriers can help provide excellent ventilation while maintaining consistent temperature control in different weather conditions.

Enhanced Comfort

Under house insulation can make a significant difference in the level of comfort you experience inside your raised home. With proper insulation, you can maintain a consistently comfortable indoor temperature throughout the year.

Insulation works by keeping heat from escaping during cold weather and preventing heat from entering during warm weather. This means that you no longer have to worry about feeling chilly on winter nights or sweltering in summer afternoons.

Studies show that improved thermal resistance (R-value) provided by proper insulation increases homeowner satisfaction with their homes' overall comfort levels. For those dealing with hot and humid weather conditions, these benefits are even more significant as it makes the indoor environment pleasant even in extreme temperatures outside.

Reduced Moisture And Mold Growth

Under house insulation for a raised house can effectively reduce moisture and mold growth. Moisture is a common problem in crawl spaces, which often have high humidity levels because they are located below ground level.

This moisture can contribute to the growth of mold and mildew, which can be harmful to human health.

Insulation also helps to minimize moisture-related problems such as wood rot and structural damage by providing an effective seal against dampness. Closed-cell sprayed foam or rigid XPS foam boards are excellent options for those looking for maximum protection against water infiltration since they act as vapor barriers that block moisture penetration altogether.

Increased Durability

Under house insulation for a raised house not only helps to improve energy efficiency and indoor air quality, but it also increases the overall durability of the structure.

By reducing moisture and mold growth, insulation helps prevent damage to the subflooring and floor joists which can lead to costly repairs. It also acts as a thermal barrier that protects against temperature changes, keeping floors from shrinking or expanding due to fluctuations in temperature.

Choosing durable insulation materials such as closed-cell sprayed foam or rigid XPS foamboards will give your home long-lasting protection while reducing maintenance costs in the future.

Types Of Under House Insulation

There are various types of under house insulation available, including rigid XPS foamboards, spray foam between studs, fiberglass batts, open-cell sprayed cellulose, closed-cell sprayed foam, and reflective insulation.

1. Rigid XPS Foamboards

Rigid XPS foamboards are a popular choice for under house insulation and can be used to insulate on top of the subfloor. They are easy to install, lightweight, and have excellent thermal resistance properties.

Additionally, they are moisture-resistant and will not degrade over time. One advantage of rigid foam insulation is that it provides an air barrier when installed correctly.

This reduces drafts in your home and makes it more comfortable while also help conserve energy at home.

2. Spray Foam Between Studs

Spray foam insulation is an effective way to insulate between the studs of walls and partitions. Here are some things to keep in mind:

1. Spray foam insulation can provide an airtight seal, preventing air leaks and improving energy efficiency.

2. It can also help reduce noise transmission between rooms.

3. Spray foam is ideal for hard-to-reach areas and irregularly shaped spaces.

4. Choosing closed-cell spray foam provides the added benefit of moisture resistance.

5. It's important to hire a professional insulation contractor for spray foam installation to ensure proper application and safety precautions.

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3. Fiberglass Batts

Fiberglass insulation batts have been a staple in under house insulation for years. These batts are made from tiny glass fibers and come in rolls or sheets that can be cut to fit perfectly between the floor joists.

They are budget-friendly, easy to install, and readily available at most home improvement stores. Fiberglass insulation batts work by trapping air between the fibers, creating a thermal barrier that reduces heat transfer and improves energy efficiency.

Additionally, they offer soundproofing benefits and help reduce moisture levels in crawlspaces underneath raised houses.

4. Open-cell Sprayed Cellulose

1. Open-cell sprayed cellulose is made from recycled materials, making it an eco-friendly option.

2. It's a good choice for irregularly shaped spaces because it can conform to any shape or size.

3. This type of insulation has excellent sound-dampening capabilities, which can help reduce noise transmission throughout the house.

4. Open-cell sprayed cellulose is excellent at filling up gaps and cracks, helping reduce air leakage.

5. It has good moisture control properties, thanks to its ability to wick away any moisture that may get into the space.

6. Compared to closed-cell foam, open-cell spray foam is less expensive and easier to install.

Overall, open-cell sprayed cellulose is a great option for homeowners looking for an eco-friendly, cost-effective way to insulate their raised house's underfloor space while enhancing home energy efficiency and indoor comfort.

5. Closed-cell Sprayed Foam

Closed-cell sprayed foam is a type of under house insulation that provides excellent air sealing and high R-value per inch. This type of insulation creates a barrier against moisture, preventing mold growth and increasing the durability of the structure.

Closed-cell sprayed foam is ideal for homes in hot and humid climates, as it can withstand high levels of humidity without losing its insulating properties. It is also eco-friendly, as it does not emit harmful chemicals into the environment.

6. Reflective Insulation

Reflective insulation is another type of under house insulation that is becoming more popular due to its energy efficiency and ease of installation. Here's what you need to know about reflective insulation:

1. Reflective insulation works by reflecting heat radiation away from the house, rather than absorbing it like other insulation types.

2. This type of insulation typically consists of a layer of foam or fiberglass with a shiny aluminum foil layer on one or both sides.

3. Reflective insulation is often used in warmer climates where keeping the house cool is a priority.

4. It can be installed by simply stapling the material onto the underside of the floor joists.

5. When combined with other types of insulation, such as fiberglass batts, reflective insulation can provide additional energy savings.

When considering under house insulation options, it's important to consider climate, budget, and installation requirements before making a decision. Reflective insulation can be a great choice for those living in warm climates who are looking for an effective and easy-to-install solution for reducing energy costs.

under house insulation raised house

Factors To Consider When Choosing Under House Insulation

Consider the climate, budget, moisture issues, installation process, and professional assistance when choosing under house insulation.


The climate is an important factor to consider when choosing under house insulation. Here are some points to keep in mind:

1. Hot and humid climates require insulation that can resist moisture and mold growth, such as closed-cell sprayed foam or rigid foam insulation board.

2. Colder climates require insulation with a high R-value, such as fiberglass batts or cellulose batts, to provide maximum thermal resistance.

3. In areas with extreme temperature fluctuations, reflective insulation may be the best option since it reflects heat during hot summers and retains warmth during cold winters.

4. Eco-friendly insulation options, like recycled denim or wool, work well in mild climates but may not provide enough protection in harsher environments.

5. Homeowners should consult a professional to determine the best type of insulation for their specific climate conditions and budget.


One of the essential factors to consider when choosing under house insulation for a raised home is the budget. Different types of insulation materials come at different prices, and some may be more expensive than others.

For example, spray foam insulation typically costs more than fiberglass batts or rolls.

However, it's important to keep in mind that investing in high-quality under house insulation can lead to long-term savings by reducing energy bills and increasing the overall lifespan of a home's structure.

Moreover, there are eco-friendly options available that can help save on both energy consumption and expenses over time.

Moisture Issues

Moisture control is a critical aspect of under house insulation installation. Moisture issues can cause damage to the subfloor, floor joists, and insulation material. Here are some common moisture issues to consider:

1. Plumbing leaks: Leaks from plumbing fixtures or pipes can cause water to accumulate in the crawl space or basement, leading to mold growth and rot.

2. Ground moisture: If there is high humidity or excessive ground moisture, it can seep into the crawl space and cause problems.

3. Flooding: The homeowner must take precautions if their area is prone to flooding to avoid severe water damage to flooring and insulation.

4. Poor ventilation: Inadequate ventilation in the crawlspace can lead to condensation that encourages mold growth.

5. Lack of vapor barrier: If there is no vapor barrier installed, the rising moist air from soil will permeate the fibers of the insulation and render them ineffective over time.

6. Air leaks: Air leaks around windows, doors, walls, and floors can cause high humidity levels in the home and promote mold growth.

It is important to address any moisture issues before installing under house insulation. A professional contractor may be able to help identify potential problem areas and suggest appropriate solutions such as encapsulation for flood-prone areas or installing proper ventilation for humid climates. Selecting an adequate insulation material with built-in vapor barriers specifically designed for under-house usage can also play a vital role in moisture management measures.

Installation Process

To install under house insulation for a raised house, start by preparing the crawlspace. This includes removing debris and repairing any damaged foundations or supports. Next, measure and cut the insulation to fit tightly between the floor joists.

Then, install the chosen type of insulation by either stapling it in place or using wire mesh to hold it up.

It's important to note that installation processes can vary depending on factors such as climate, budget, and moisture issues. It may be necessary to hire a professional contractor for proper installation and assessment of individual needs.

Professional Assistance

Professional assistance can be invaluable when insulating the underside of a raised house. Here are some reasons why:

1. Assessing the specific insulation needs based on climate, budget, and moisture issues.

2. Choosing the right type of insulation material for best results and durability.

3. Ensuring proper installation to optimize thermal resistance and energy efficiency.

4. Providing additional ventilation if necessary to prevent moisture buildup and mold growth.

5. Removing old insulation safely and properly if needed.

6. Sealing air leaks effectively to prevent heat loss or gain.

7. Following local building codes with respect to insulation installation.

Professional assistance can also save time and labor for homeowners who may not have the tools or expertise required for a successful under-house insulation project. In addition, some professional installers offer eco-friendly options that use sustainable materials or recycled content, which can reduce environmental impact while improving indoor comfort and air quality.

How To Install Under House Insulation

To install under house insulation, start by preparing the crawlspace, measure and cut the insulation to fit between floor joists or on top of subflooring, then attach it in place with adhesive or wire fasteners.

Preparing The Crawlspace

Before installing under house insulation in a raised house, it's essential to prepare the crawlspace to ensure that the installation process goes smoothly. Here are some steps to take:

1. Clean up the area: Remove any debris, old insulation, or pests from the crawlspace. Use a broom or vacuum cleaner to sweep away cobwebs and dust.

2. Seal air leaks: Look for any gaps or holes in the crawlspace walls that could let air in or out. Seal them with caulk or expanding foam.

3. Address moisture issues: Check for any sources of water damage, such as leaky pipes or standing water. Fix these issues before installing insulation to prevent mold growth.

4. Measure and cut insulation: Measure the distance between floor joists and cut insulation batts to fit snugly between them.

5. Lay down a vapor barrier: Cover the ground with a moisture-resistant material like plastic sheeting to prevent moisture from seeping through.

6. Install insulation: Place the pre-cut batts between floor joists, making sure they fill up all space without leaving gaps.

7. Seal around wires and pipes: Use expanding foam to seal around any electrical wires or pipes running through floor joists when necessary.

By following these steps, you can ensure that your under-house insulation is installed correctly and will provide maximum benefits to your raised house, including increased energy efficiency and improved indoor air quality while preventing mold growth and enhancing comfort for years ahead.

Measuring And Cutting The Insulation

Before installing the insulation, accurate measurements and proper cuts are crucial to ensure maximum efficiency. Measure the distance between each floor joist and cut the insulation accordingly.

It's important to make sure that the insulation fits snugly in between each joist without any gaps or spaces.

It's also important to take safety precautions when measuring and cutting fiberglass batts. Wear protective gear such as gloves, safety glasses, and long sleeves to avoid irritation from fiberglass particles.

Installing The Insulation

When it comes to installing under house insulation, the process can vary depending on the type of insulation being used. Here are some general steps to follow:

1. Preparing the Crawlspace: Before you install any insulation, make sure the crawlspace is clean and free of debris. If there are any moisture issues, address them before installing insulation.

2. Measuring and Cutting the Insulation: Measure the distance between your floor joists to determine how wide your insulation needs to be. Cut your insulation to fit snugly between each joist.

3. Installing the Insulation: For fiberglass batts or rolls, simply fit them between each floor joist with no gaps or spaces. For rigid XPS foamboards or spray foam, use adhesive or special fasteners to secure the boards in place.

4. Sealing Air Leaks: To maximize energy efficiency and prevent air leakage, seal any gaps or cracks around your insulation using caulk or spray foam. This will also help keep out moisture and pests.

5. Encapsulating if Needed: In some cases, encapsulating under a raised house may be necessary for added protection against moisture and pests.

Remember that proper installation is key for achieving maximum benefits from your under house insulation. If you're not confident in doing it yourself, consider hiring a professional insulator for guidance and assistance.

Sealing Air Leaks

One important factor to consider when installing under house insulation is sealing air leaks. Even with the best insulation, air leaks can significantly reduce its effectiveness in improving energy efficiency and reducing moisture.

Air leaks can also lead to indoor drafts and poor air quality.

To seal air leaks, homeowners should start by identifying areas where there may be gaps or cracks between the walls and floors. Common culprits include electrical wiring, plumbing fixtures, and venting systems.

Foam insulation works excellently around wire entry points while spray foam can be used between studs of walls and partitions for better sealing effectiveness.

Insulating Raised Floors In Hot, Humid Climates

insulating raised floor

When it comes to insulating raised floors in hot, humid climates, it's important to choose the right materials and installation method. In this section, we'll explore the best insulation materials for your home and offer tips on how to enclose your elevated house for maximum thermal resistance.

Importance Of Insulation In Humid Climates

Humid climates can wreak havoc on homes, making proper insulation crucial. Without adequate insulation, hot and humid air can easily penetrate the interior of a raised house through gaps in the floorboards or walls.

This leads to increased moisture and mold growth, which not only damages structures but also poses health risks to residents. Proper insulation helps create a thermal barrier that keeps humidity out and reduces energy consumption by preventing warm air from escaping the home.

Fiberglass batts or spray foam are great options for this type of underfloor insulation as they provide both thermal resistance (R-value) and moisture resistance benefits.

Enclosing Under Elevated House

One of the best ways to insulate a raised house is by enclosing the area beneath it. This involves creating a barrier around the floor joists, which helps prevent moisture and air from entering the space.

Enclosing under an elevated house can be done using various materials such as concrete, cinder block walls, or wood framing with exterior-grade plywood sheathing. In hot and humid climates where moisture buildup can be a problem, it's essential to use materials that are resistant to water and mold growth.

Insulating A Floor Built On Piers

Insulating a raised house with a floor built on piers is important to save energy and increase comfort. Here are some tips for insulating a floor built on piers:

1. Install insulation batts or rolls in between the joists.

2. Use rigid XPS foam boards to insulate the underside of the subfloor.

3. Seal any air leaks between the insulation and joists with spray foam.

4. Consider enclosing the crawlspace under the elevated house with ventilation to control moisture if it's located in a hot, humid area.

5. Choose insulation materials that are resistant to moisture and have high R-values to provide excellent thermal resistance and energy efficiency.

6. Hire professional contractors if you're not confident about DIY installation process, it can help ensure proper installation of your under house insulation.

Insulating under raised floors built on piers may present unique challenges due to limited access to crawlspaces, but proper insulation can help keep your home comfortable year-round while reducing energy bills significantly.

under house insulation for a raised house-conclusion

Under house insulation is a vital aspect of maintaining energy efficiency and improving the comfort of your raised house. Whether you opt for fiberglass batts, spray foam, or rigid XPS foamboards, the benefits are undeniable - from reduced mold growth to enhanced indoor air quality.

Choosing the right type of insulation will depend on various factors such as climate, moisture issues, and your budget. While it may be tempting to take on this project yourself, professional assistance can ensure that it is installed correctly and effectively. So don't let your raised house suffer from inefficient insulation! Consider upgrading today and enjoy a more comfortable and eco-friendly living space.