Prefab Underground Shelters: Benefits, Types, and Installation

Prefabricated house, workers in setting up the basement walls on building site, Bavaria, Germany, Europe, April 03, 2016

A well-built storm shelter is crucial for protecting your family and property from severe weather. Prefabricated underground storm shelters are a popular choice due to their effectiveness, affordability, and easy installation.

These shelters are made from reinforced concrete or steel and come in different sizes. They are built off-site and then transported for installation.

Prefab underground storm shelters offer superior protection, quick installation, and high safety standards. They can also increase property value. This guide focuses on prefab underground storm shelters.

Choosing the Right Shelter: Above-Ground vs Below-Ground

When deciding on the type of shelter to install, it’s important to consider several factors, including the nature of weather threats in your area, the size of your family, and your budget. Let’s look at the characteristics of both above-ground and below-ground storm shelters.

Above-Ground Shelters

Above-ground storm shelters are typically installed in garages or basements, bolted to the foundation to prevent displacement during a storm.

They are constructed from heavy-duty materials like reinforced steel and come with sturdy doors that lock from the inside. These shelters are easily accessible, particularly for individuals with mobility issues. However, they might be less effective against flying debris than their underground counterparts.

Pros and Cons

Above-ground shelters offer the benefits of easy access, quicker installation, and generally lower costs. They are an excellent choice for people with mobility issues who may struggle with stairs leading to underground shelters.

On the downside, they may not offer the same level of protection as underground shelters, especially against severe tornadoes or hurricanes.

Below-Ground Shelters

Below-ground storm shelters are installed under the ground level, either in the yard or underneath the garage floor. They are designed to resist high winds and flying debris, offering superior protection in case of severe storms.

Usually made from concrete or reinforced steel, these shelters are accessed via a stairway and feature a heavy-duty door that locks from the inside.

Pros and Cons

Below-ground shelters offer excellent protection against extreme weather conditions, including high winds and flying debris.

Being underground, they inherently provide a higher level of safety compared to above-ground structures.

However, they can be challenging to access for individuals with mobility issues, and their installation can be more complex and time-consuming compared to above-ground shelters.

Construction of Prefab Underground Storm Shelters

The construction process of prefab underground storm shelters involves several critical steps, from the selection of the right materials to the design of the shelter.

Materials Used in Construction

In building durable and reliable storm shelters, choosing the right materials is paramount. The two most common materials used are steel and concrete, each offering unique advantages.

Steel Shelters

Steel shelters are known for their strength and resistance to impacts, making them an excellent choice for storm shelters. They are typically constructed from heavy-gauge steel and reinforced with additional layers for added strength. Despite their durability, steel shelters are relatively lightweight, making them easier to handle during installation.

Concrete Shelters

Concrete shelters, especially those reinforced with steel, are another popular choice due to their robustness and resistance to high winds. Concrete shelters are often precast into in-ground or above-ground designs, providing flexibility in terms of placement. While heavier than steel, concrete has excellent thermal properties, keeping the interior of the shelter cool in hot weather and warm in cold seasons.

Design of Storm Shelters

The design of a storm shelter largely depends on its intended use. Residential shelters are typically smaller and designed for a few occupants, while commercial shelters are larger to accommodate more people.

Residential Storm Shelters

Residential storm shelters are usually designed to accommodate between 4-12 people. The size you choose will depend on the size of your family and whether you plan to house neighbors or pets.

These shelters often come with seating and storage space for emergency supplies.

Commercial Storm Shelters

Commercial storm shelters are bigger to accommodate a larger number of people, such as employees in a workplace.

They may also feature additional amenities like restrooms and more extensive storage facilities for supplies. The design of these shelters must also consider easy access and exit routes for a large group.

Installing a Prefab Underground Storm Shelter

Installing an underground storm shelter involves several critical steps, including site preparation, excavation, shelter placement, and backfilling. Let’s take a closer look at each stage.

DIY Installation vs Professional Installation

While some homeowners with a strong background in construction may choose to install their prefab storm shelter, it’s generally advisable to leave this task to professionals. This ensures that the installation is done correctly, and the shelter meets all safety standards. Improper installation can lead to problems down the line, such as water leakage or even collapse.

Planning the Location of Your Shelter

Choosing the right location for your storm shelter is an important decision. It should be easily accessible from your home, ideally within a few steps.

If you’re installing the shelter in your yard, pick a spot that’s free from large trees or other structures that could potentially damage the shelter during a storm. For shelters installed under the garage floor, ensure there’s enough space for excavation and installation.

Considering Accessibility, Safety, and Convenience

In addition to choosing a suitable location, you also need to consider factors like accessibility, safety, and convenience. The entrance should be easy to access for all family members, including those with mobility issues. The shelter should be located in a safe area where it’s unlikely to be affected by falling trees or power lines. Convenience is another factor to consider; the shelter should be close enough to your home for quick and easy access during a storm.

Steps in Shelter Installation

Installing a prefab underground storm shelter typically involves the following steps: First, the site is prepared and marked for excavation. Then, a hole is dug to the required specifications. Once the excavation is done, the prefab shelter is placed into the hole, ensuring its level.

After placement, the space around the shelter is backfilled with soil, and the surface is leveled. Finally, the shelter door is installed and tested to ensure it opens and seals properly.

Features of a Well-Designed Storm Shelter

Storm cellar under a barn.

A well-designed storm shelter boasts several key features that enhance its safety, durability, and comfort. These include robust construction, adequate insulation and ventilation, and a secure door design.

Durability of the Shelter

A storm shelter’s durability largely depends on its construction materials and design. As mentioned earlier, steel and concrete are the most common materials used due to their strength and resistance to high winds and impacts. The shelter should be designed to withstand extreme weather conditions, including tornadoes and hurricanes.

Insulation and Ventilation Considerations

Good insulation is crucial for maintaining a comfortable temperature inside the shelter, especially during hot or cold seasons. Concrete shelters, in particular, offer excellent thermal properties. Ventilation, on the other hand, ensures a steady supply of fresh air, which is vital when the shelter is occupied for extended periods. Most storm shelters are equipped with vents that allow for air exchange while keeping out rain and debris.

The Importance of Door Design

The door of a storm shelter is one of its most critical components. It should be sturdy enough to withstand high winds and flying debris, and it should feature a secure locking mechanism from the inside. Additionally, the door should open inward to ensure it can be opened even if debris is piled against it from the outside.

Maintaining Your Storm Shelter

Regular maintenance of your storm shelter can ensure it remains in top condition and ready for use whenever needed. This involves regular inspections, cleaning, and stocking of emergency supplies.

Regular Maintenance Tasks

Regular maintenance tasks for your storm shelter include checking the door and its locking mechanism, inspecting the ventilation system, and looking for any signs of water leakage or damage.

The interior should be kept clean and free of pests. Any issues found during an inspection should be addressed promptly to ensure the shelter’s effectiveness.

Emergency Supplies to Stock in Your Shelter

Emergency backpack equipment organized on the table in the living room

Having the right supplies in your shelter can make a significant difference in an emergency. These should include drinking water, non-perishable food, a first aid kit, flashlights with extra batteries, a battery-operated radio, blankets, and personal hygiene items. Remember to replace these supplies regularly to ensure they’re fresh and usable when needed.

Dealing with Potential Issues and Repairs

Despite regular maintenance, issues may arise over time. Common problems include door malfunctions, water leakage, or ventilation issues. Depending on the severity of the problem, you might need to call in professionals for repairs. Addressing these issues promptly ensures your shelter remains reliable and ready for use.

Regulations and Standards for Storm Shelters

When installing a storm shelter, it’s important to be aware of local laws, building codes, and industry standards established by organizations like the Federal Emergency Management Agency (FEMA).

Understanding Local Laws and Codes

Local laws and building codes vary by location, so it’s essential to check with your local authorities before installing a storm shelter. Some areas may require permits, while others have specific guidelines on shelter size, placement, and design. Non-compliance with these regulations can lead to fines or other penalties.

Choosing a Manufacturer that Meets Standards

Selecting a reputable manufacturer that meets or exceeds safety standards is crucial. Ask potential manufacturers about their compliance with local building codes and FEMA safety standards. Also, inquire about warranties and guarantees they offer, which can provide additional peace of mind.

Cost Considerations for Prefab Underground Storm Shelters

While safety should be the primary concern, cost is a practical consideration when choosing a storm shelter. It’s important to understand not only the initial purchase and installation costs but also any potential additional costs.

Initial Purchase and Installation Costs

The initial cost of a prefab underground storm shelter can vary greatly depending on its size, material, and design. Concrete shelters typically range from $3,700 to $7,000+ installed, while steel shelters can cost between $4,500 to $20,000+. Keep in mind that these prices are estimates and can vary based on factors such as location, customization options, and additional features. It’s recommended to obtain quotes from different manufacturers to compare prices and features before making a decision.

Potential Additional Costs

In addition to the initial purchase and installation costs, there may be other expenses to consider. These can include site preparation, excavation, permits, professional labor fees, and any necessary modifications to your property. It’s important to factor in these potential costs when budgeting for your storm shelter project.

FAQs about Prefab Underground Shelters

Here are some frequently asked questions that homeowners often have when considering the installation of a prefab underground storm shelter.

What is the cheapest underground tornado shelter?

The cost of an underground tornado shelter can vary depending on various factors, including size, material, and features. Generally, steel shelters tend to be more affordable compared to concrete ones. However, it’s important to prioritize safety and ensure that the shelter meets all necessary standards and regulations, even if it means investing a bit more upfront.

Can you build your own underground storm shelter?

While it’s possible to build your own underground storm shelter if you have a strong background in construction, it’s generally recommended to leave this task to professionals. Professional installation ensures that the shelter meets safety standards and regulations, minimizing the risk of structural issues or failure during a severe weather event.

What is the best basement shelter for tornadoes?

Basement shelters, whether above-ground or below-ground, can provide a certain level of protection during tornadoes.

However, it’s important to note that not all homes have basements, and even if they do, basements may not offer the same level of protection as purpose-built storm shelters. Ultimately, a well-designed and properly installed prefab underground storm shelter offers the highest level of safety during severe weather events.

By Anita Brown

Anita Brown is our go-to contributor to our emergency preparedness website. Anita brings a wealth of personal experience and professional expertise to the table, having weathered several awful natural disasters. Anita is currently working towards obtaining her Community Emergency Response Team (CERT) certification.