There are many rules, building codes, and zoning ordinances that guide outdoor living projects in Raleigh, Durham, and the greater Triangle. Many property owners are familiar with the need to obtain a building permit and subsequent inspections for safety, but many do not know about the environmental regulation limiting impervious surface areas. If you’re planning to add to, renovate, or alter your property in any way, staying in compliance with impervious surface limits is an important consideration.
Impervious surface limits can significantly affect your proposed outdoor living project by restricting the amount of hard, non-porous surfaces like concrete or pavers you can install on your local property. These limits can impact the size of your patio, deck, or other structure(s) due to regulations designed to manage stormwater runoff and protect water quality by encouraging water infiltration into the ground. Exceeding impervious surface limits could result in permit denials, fines, or limits on future development plans. Owner Kyle Faulkner, put together this informative video to easily explain what and how these impervious surface limits work:
What is an impervious surface limit?
An impervious surface limit is the amount of surface area on your property that can be covered by a material that significantly reduces the natural drainage of water into the soil. Land covered by materials such as concrete, stone, wood, or asphalt – which are commonly used in driveways, sidewalks, patios, and decks – count as an impervious surface area.
.jpg)
Impervious limits are monitored by local Stormwater Management Offices and vary by locale. Regulating impervious surface areas is an environmental effort to promote a healthy drinking water supply. Rainwater that runs off of these surfaces can flow back into the drinking water supply without the benefit of filtration through the soil, and raise the risk of contaminating the local drinking water.
What if I exceed my impervious surface limit?
When preparing for a new outdoor living expansion, you will need to find out if you are currently complying with your impervious surface limits and, if so, how much room remains on which you can build. Homeowners who exceed their impervious surface limits will be responsible for removing materials in order to comply.
Archadeck can help you determine the impervious surface limits of your property. If you discover you have already exceeded or are at risk of reaching the limits, we may be able to find design solutions to achieve your project goals while staying within the limits. While this may mean some alterations in your project’s scope, it could be as simple as adding a special infiltration device, rain garden, or cistern to comply.
What is my impervious surface limit?
.jpg)
Impervious surface limits vary widely from county to county, city to city, town to town, and even from neighborhood to neighborhood. For example, the unincorporated parts of Wake County, outside of watershed areas, have a 30% impervious surface limit. The City of Raleigh has five zoning districts, each with a different impervious surface limit. You can look up your property through iMAPS to determine your specific impervious surface limit. These limits will be anywhere from 20%-65%. With such a broad range, it is vital for a homeowner to get the precise limit for their specific address from the local municipality.
What documentation is required to add impervious surfaces to my yard?
When adding on to your home, a survey or plot plan is required to be submitted to the building department as part of the permitting process to ensure you are staying within your impervious surface limits. The surveyor plot plan should be completed by a licensed surveyor and indicated existing and proposed additions to your home. (If you do not already have a survey or plot plan, Archadeck can connect you with a licensed surveyor. Surveys can be used for any additional home improvements you may do in the future.) A stormwater tracking permit will then be issued for projects subject to the impervious surface limits.
Key points about impervious surface limits and outdoor projects
- Impact of your proposed design: When Archadeck is designing your outdoor space, both you and our designer will need to consider the local impervious surface limits of your property. This is to ensure your project falls within the allowed percentage of hard surfaces on your property.
- Material selection: Making the decision to use permeable paving materials like permeable pavers or gravel can help you maximize the useable space while still adhering to impervious surface limits. There are options.
- Stormwater management: Consider adding features like rain gardens, bioswales, or rain barrels to help manage stormwater runoff from impervious surfaces on your property.
- Permits and regulations: Before starting any outdoor project always check with your local zoning or planning department to understand the specific impervious surface requirements in your area and those specific to your property.
When you work with Archadeck of Raleigh-Durham for your deck, patio, porch, or combination project, we will identify your impervious surface limit, submit a survey or plot plan, and obtain subsequent permits and inspections on your behalf.
Check out related content:
Can My Deck Be Converted to a Screened Porch?
Raleigh-Durham Deck Builder
Composite Deck Builder
Deck Gallery
Composite Deck Gallery
