Protecting and Preserving Topsoil During New Home Construction
Question: I’ve contracted to have a new home built and groundbreaking starts soon. What measures should be taken prior to and during construction to preserve and protect the topsoil and native plants on my site?
By Carla Throckmorton, Piedmont Master Gardener Intern
The details involved in building a new home make it an exciting but stressful time. Once the site is chosen, there are many decisions to make to ensure the new home reflects the buyer’s taste and lifestyle. Actions to preserve and enhance the special landscape that attracted the buyer are often neglected until long after move-in day.
What Happens to Topsoil During Construction?
Leaving topsoil in place during construction presents problems for builders. Removing much of the topsoil is necessary to prepare for roadbeds, sewer lines, building foundations and utilities. Topsoil contains a huge number of microorganisms that are constantly breaking down organic matter. As a result, topsoil is removed because foundations and other infrastructure built on topsoil settle unevenly as this organic matter decomposes. The remaining subsurface soil is often low in nutrients and organic matter that enriches the soil and supports plant life. Heavy construction equipment also compacts the soil which restricts both root growth and the plant’s uptake of water. Unless topsoil is redistributed or replaced and the effects of compaction are reduced after construction, plants and trees will suffer. In addition, topsoil removal can have a serious impact on stormwater management and can be costly to the homeowner.
Although Virginia does have laws regulating topsoil removal, storage and redistribution after construction, home owners need to take a few proactive steps to ensure that post-construction landscaping is successful.
Image source: Peter Robbins, Unsplash
The Benefits of Topsoil
Good topsoil is a valuable natural resource, which is essential to support healthy plantings and trees in the home landscape. It provides the pH level, nutrients, moisture, organic matter and soil structure in which plants thrive. In addition, it helps prevent erosion and limits stormwater runoff, which contributes to flooding and pollution of our waterways. By preserving topsoil on their properties, homeowners not only enhance the beauty of their own landscape but are helping to keep the local ecosystems healthy.
Plan Before Construction Begins
It is important to develop a plan to address topsoil removal and compaction before construction starts. Be sure to consider ways to minimize soil disturbance by limiting the “construction footprint” but leaving adequate space for construction.
- Decide whether specific plants or trees should remain outside the construction zone.
- Define areas to be protected and those that have to be disturbed and restored later. Take into account the placement of the driveway, sidewalk, patio, and other landscape features.
- Decide where any topsoil can be stored on site and how it will be redistributed later or plan for topsoil removal and replacement after construction.
- Sketch out the plan on a property map and discuss it with your building contractor and project managers, making sure everyone agrees to the plan. Avoid major changes to the topography of the landscape, which can affect drainage patterns and negatively impact plantings.
Doing the earth-moving and post construction soil preparation in dry weather will limit damage to the soil. Using the lightest, smallest construction equipment possible in the smallest area can also reduce the area affected by compaction of the soil.
If possible, have the plan included in the construction contract. Buyers of custom-built houses or homes in small volume developments may have more leverage to persuade contractors to change construction contracts. However, even builders of large housing developments may be amenable to some changes.
Image source: Jason Jarrach, Unsplash
Implementing the Plan
Do a soil test of your topsoil and subsoil before restoring the site and make sure to adopt any recommendations on adjusting pH, applying fertilizer and adding other amendments. This will help ensure that the restored site supports healthy plantings.
- If possible, set aside and stockpile topsoil on the building site in long low berms rather than in a high compact pile and surround with construction fencing or other temporary barriers. If topsoil piles remain in place for a long period of time, sow a cover crop to enrich the soil or cover them with woven weed barrier fabric. Overlap the edges of the fabric by at least one foot and weigh down or tape the seams. The topsoil should be redistributed as soon as construction is finished.
- Whether redistributing stockpiled topsoil or returning topsoil to the site, apply enough amended, uncompacted soil to cover the disturbed ground to a depth of 12 inches. Purchase high-quality topsoil, if necessary. Till the subsoil to a depth of 4 inches first and then apply 8 inches of amended topsoil (5 inches of topsoil plus 3 inches of compost). The resulting soil should be about 2 inches higher than grade to allow for the settling of soil over time.
- Shred, grind or chip removed vegetation to use as mulch on your restored site to save on costs of removal.
- Do not till too close to tree roots or pile soil or in “mulch volcanos” around tree trunks.
- Spread mulch on all restored planting beds and protect against future soil compaction.
Other Methods of Conservation Landscaping
Promoting healthy soils, planting native plants, and improving water quality reflect three of the eight essential principles of conservation landscaping. In addition to protecting and preserving the topsoil, there are many other ways to adopt conservation landscaping practices on your property. Consider adding more native plants to your site. Adapted to the local soils and growing conditions, they require less water and fertilizer once established, provide food and shelter for wildlife and support healthy ecosystems. Avoid use of invasive plants and learn how to control their spread. Every small action you take can make a difference.
Featured Image: Billy Freeman, Unsplash.
References
“Combating Soil Compaction”, Pineo, Rebecca, Botanic Garden Intern & Barton, Susan, Extension Specialist, University of Delaware, College of Agriculture & Natural Resources, Cooperative Extension, Oct 2024.
“How to Preserve and Restore Healthy Soil”, Washington Organic Recycling Council.
“How Do You Protect a Tree During Construction?”, University of New Hampshire, UNH Extension, 3 Aug 2020.
“It Is Possible To Restore Soil For Successful Landscaping Around Newly Constructed Homes”, Chicago Tribune, 11 Aug 2021.
“Protecting Your Soil During Construction”, Pierce Conservation District, Washington State.
“Sustainable Landscape at Home”, Ask A Master Gardener, Piedmont Master Gardeners, 4 Aug 2021.
“The Eight Essential Elements of Conservation Landscaping”, Chesapeake Conservation Landscaping Council.
“The Soil Around Your Newly Constructed Home May Not Be What You Bargained For”, Chicago Tribune, 11 Aug 2021.
“The Trend Toward Conservation Landscaping”, Piedmont Master Gardeners, 20 Nov 2021.
“To Clear or Not to Clear”, Downing, Adam et. al., Forestry and Natural Resources Extension Agent, Northern District, Virginia Tech, Virginia Cooperative Extension, publication 465-340, 2022.
“Using Compost In Your Landscape”, Niemiera, Alex, Extension Specialist & Michael Goatley, Horticulture, Virginia Tech, Virginia Cooperative Extension, publication 426-704, 13, Mar 2021.