How To Fill In A Fiberglass Swimming Pool – A Permanent Solution
Maintaining an aging pool can quickly become a drain on your time, energy, and financial resources. If you are ready to reclaim your backyard for a sustainable garden or a new outdoor living area, learning how to fill in a fiberglass swimming pool is the first step toward a more self-sufficient lifestyle.
This guide provides a clear, safety-first roadmap to help you navigate the complexities of pool removal and land restoration. We will cover everything from legal permits and drainage requirements to the best materials for a stable, long-lasting finish.
By the end of this article, you will have the confidence to transform that unused water feature into a functional part of your homestead. Let’s dive into the practical steps required to complete this project successfully and safely.
Table of Contents
Understanding the Preliminary Steps and Legal Requirements
Before you pick up a shovel or hire a contractor, you must address the legal and logistical aspects of the project. Every municipality has different rules regarding land modification and permanent pool decommissioning.
Contact your local building department to inquire about necessary permits for pool demolition. Some areas require a specific “pool abandonment” permit that dictates exactly how the structure must be handled to remain compliant.
You must also locate your utility lines before any heavy machinery arrives on your property. Call your local utility marking service to identify underground power, water, and gas lines to avoid catastrophic accidents during the excavation process.
Consulting with Structural Experts
If you plan to build a structure, such as a shed or a heavy pergola, over the old pool site, consult a structural engineer. Filling a pool creates a “non-engineered fill” zone that may not support heavy loads without specialized compaction techniques.
Even if you only want a garden, an expert can advise on how to prevent future sinkholes. Understanding the soil composition in your specific region is vital for ensuring the ground remains level for years to come.
Safety should always be your primary concern when managing large-scale backyard projects. Keep children and pets away from the site, and always wear protective gear, including gloves and safety glasses, during the demolition phase.
how to fill in a fiberglass swimming pool: The Step-by-Step Process
The actual process of how to fill in a fiberglass swimming pool involves more than just dumping dirt into a hole. Fiberglass shells are non-porous, meaning they can act like a giant bowl that traps water if not handled correctly.
First, you must completely drain the pool using a submersible pump. Ensure the water is discharged according to local environmental regulations, as chlorinated water can harm local ecosystems and neighboring landscapes.
Once the shell is empty, you need to address the structural integrity of the fiberglass. Unlike concrete pools, fiberglass can “pop” out of the ground due to hydrostatic pressure if the surrounding groundwater levels are high.
Breaking the Bottom for Proper Drainage
To prevent the pool from becoming a subterranean swamp, you must create drainage holes in the bottom of the shell. Use a heavy-duty drill or a jackhammer to punch several large holes through the fiberglass floor.
Aim for holes that are at least 12 inches in diameter, spaced roughly every three to four feet. These openings allow rainwater to pass through the fill material and into the natural water table below.
Without these holes, the filled area will remain perpetually saturated. This leads to unstable ground, foul odors, and the potential for the entire fill to shift or “float” over time.
Removing the Coping and Top Rim
You do not necessarily need to remove the entire fiberglass shell, but you must remove the top 18 to 24 inches. This top section, known as the coping and rim, would otherwise interfere with landscaping and lawn growth.
Use a circular saw with a diamond blade or a reciprocating saw to cut away the upper portion of the fiberglass. Be extremely careful, as fiberglass shards are sharp and can cause respiratory irritation if inhaled.
Once the top rim is removed, the remaining shell stays in the ground to act as a container for your fill material. This method is often called a “partial removal” and is the most common choice for budget-conscious homesteaders.
Selecting the Best Fill Materials for Stability
The quality of the material you put into the hole determines the success of your project. You cannot simply use “free dirt” from an unknown source, as it may contain organic debris that rots and causes settling.
Start with a base layer of clean gravel or crushed stone at the very bottom, covering your drainage holes. This layer, usually about 12 inches deep, ensures that water can move freely toward the punched openings.
Gravel provides a solid foundation that does not compress significantly over time. It is an essential component for any long-term land reclamation project involving non-porous structures like fiberglass shells.
Using Structural Fill and Subsoil
Above the gravel, you will use structural fill or “clean fill,” which consists of inorganic soil, sand, and small stones. This material should make up the bulk of the filling volume because it compacts well.
Avoid using soil with high clay content if possible, as clay retains moisture and expands or contracts with the seasons. Instead, look for a sandy loam or a specific “engineered fill” from a local quarry.
As you add the fill, work in “lifts” or layers of about 6 to 8 inches at a time. Attempting to fill the entire pool at once will lead to massive settling and dangerous sinkholes later in the year.
The Importance of Quality Topsoil
The final 12 to 18 inches of the pool should be filled with high-quality topsoil. This is the layer where your vegetation will grow, so it needs to be rich in nutrients and organic matter.
If you plan to turn this area into a vegetable garden, ensure the topsoil is screened and free of large rocks. Investing in premium soil now will pay dividends when you begin planting your homestead crops.
Remember that topsoil will settle more than the structural fill below it. You may need to mound the soil slightly higher than the surrounding grade to account for this natural compression over the first few months.
Compaction Techniques to Prevent Future Sinkholes
Compaction is the most critical step when learning how to fill in a fiberglass swimming pool. If the soil is not packed tightly, air pockets will remain, leading to significant ground depression after the first heavy rain.
For each 6-inch layer of fill you add, you must use a mechanical compactor. A vibratory plate compactor, which can be rented from most hardware stores, is the ideal tool for this job.
Run the compactor over the entire surface multiple times until the soil feels firm and does not yield underfoot. This mechanical pressure forces the soil particles together, creating a stable base for your future landscape.
Using Water for Natural Settling
Some professionals use a technique called “jetting,” which involves using water to help settle the soil. While effective for sand, you must be careful not to oversaturate the area and create a muddy mess.
A light misting of water between layers can help the particles slide into place more effectively. However, do not rely on water alone; mechanical compaction is always the superior method for preventing long-term shifting.
Continue this process of layering and compacting until you reach the desired finished grade. Patience during this phase is what separates a professional-grade project from a DIY disaster.
Managing Drainage and Hydrostatic Pressure Long-Term
Even after the pool is filled, water management remains a priority for any off-grid or homestead property. You must ensure that surface runoff does not pool directly over the old site.
Grade the finished surface so that it slopes slightly away from the center of the old pool and toward a natural drainage area. This prevents the “bathtub effect,” where the buried shell collects excess groundwater.
If your property has a high water table, consider installing a French drain around the perimeter of the old pool site. This diversion system carries excess water away before it can saturate the fill material.
Monitoring for Movement
During the first year after the project, keep a close eye on the area for any signs of localized sinking. It is normal to see some minor settling, but large depressions indicate poor compaction or drainage issues.
Keep a small stockpile of topsoil on hand to fill in any minor dips that appear after the winter thaw or heavy spring rains. Maintaining a level surface prevents water from stagnating and damaging your new lawn or garden.
Properly managing the hydrostatic balance of the soil ensures that the buried fiberglass shell remains stationary. This stability is the key to a successful transition from a pool to a productive landscape.
Transforming the Space: From Pool to Productive Land
Once the ground is stable, the fun part of how to fill in a fiberglass swimming pool begins. You now have a blank canvas to enhance your outdoor living experience and increase your self-sufficiency.
Many homesteaders choose to turn the old pool area into a raised bed garden. The deep soil provides an excellent environment for root crops like carrots and potatoes, which thrive in well-drained, loose earth.
Alternatively, you could install a fire pit area or a flagstone patio. Since the ground has been compacted, it can easily support the weight of outdoor furniture and stone pavers for a cozy gathering spot.
Planting Trees and Shrubs
If you want to plant trees, be mindful of where the remaining fiberglass shell is located. Avoid planting large taproot trees directly over the shell, as their roots may struggle to penetrate the fiberglass floor.
Instead, choose shrubs or small ornamental trees with spreading root systems. These plants will thrive in the top layers of soil without being hindered by the structural remnants of the pool below.
Creating a pollinator garden is another fantastic way to use the space. Native flowers and grasses help support local wildlife and improve the overall health of your homestead’s ecosystem.
Frequently Asked Questions About Filling in a Pool
Can I fill in a fiberglass pool without breaking the bottom?
No, you should never fill a fiberglass pool without creating drainage holes. Without them, the shell will trap water, leading to unstable ground and a “floating” shell that can damage your yard.
How much does it cost to fill in a fiberglass swimming pool?
Costs vary based on your location and the size of the pool. Generally, a DIY approach costs between $2,000 and $5,000 for materials and equipment, while professional services range from $5,000 to $15,000.
Is it better to remove the fiberglass shell entirely?
Complete removal is more expensive but allows for unrestricted future construction. Partial removal is more common for those who only want to use the area for a lawn, garden, or light patio.
Will filling in my pool decrease my home’s value?
In many cases, removing an old, high-maintenance pool can actually increase home value. Many buyers prefer a functional backyard over the liability and expense of an aging swimming pool.
Final Thoughts on Reclaiming Your Outdoor Space
Learning how to fill in a fiberglass swimming pool is a significant undertaking, but it offers immense rewards for the dedicated outdoor enthusiast. By following the correct steps for drainage and compaction, you ensure a safe and stable landscape.
Remember to take your time with the compaction process and choose your fill materials wisely. This attention to detail prevents future headaches and allows you to enjoy your new garden or patio with peace of mind.
Reclaiming your land is a powerful step toward a more intentional and self-reliant lifestyle. Whether you are planting a survival garden or building a space for family gatherings, your hard work will pay off for years to come. Stay safe and stay productive!
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