Radon mitigation system components installed in Alpharetta GA home

Radon Mitigation Systems for Alpharetta Homes

Reducing radon levels by up to 99% with the right system for your foundation

Learn about sub-slab depressurization, sub-membrane systems, and which approach works best for your Alpharetta home's foundation type.

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How Radon Mitigation Works

Every active radon mitigation system works on the same core principle: creating negative pressure beneath your foundation. A continuously running fan draws radon-laden soil gas from beneath the slab or crawl space membrane and exhausts it through a vent pipe above the roofline. This intercepts radon before it can enter your living space. Properly installed systems reduce indoor radon levels by up to 99%.

System Types

Sub-Slab Depressurization (SSD)

Slab & basement homesUp to 99%$1,000 - $2,200

A pipe is inserted through the concrete slab into the soil or aggregate below. A continuously running fan creates negative pressure beneath the foundation, drawing radon out before it enters your home and venting it above the roofline. This is the most common system type in Alpharetta.

Sub-Membrane Depressurization (SMD)

Crawl space homesUp to 99%$1,800 - $3,500

A heavy-duty polyethylene membrane is sealed over the crawl space floor and walls. A pipe and fan system draws radon from beneath the membrane and exhausts it above the roof. The membrane also reduces moisture, improving air quality.

Multi-Point Depressurization

Combination foundationsUp to 99%$2,500 - $4,500

A custom system combining sub-slab and sub-membrane techniques. Multiple suction points address radon entry from different foundation areas. Required for homes with both slab and crawl space sections, which are found in some Alpharetta custom builds.

Drain Tile Depressurization

Homes with existing drain tileUp to 99%$1,000 - $1,800

If your home has an existing perimeter drain tile system (interior or exterior), a fan can be connected to it to create depressurization. This leverages existing infrastructure and can be a cost-effective option for homes that have it.

Which System for Your Alpharetta Home?

Newer subdivision home in Windward, Webb Bridge, or North Point

Foundation: Slab-on-grade

Most straightforward installation. Single suction point typically sufficient for homes under 2,500 sq ft. Larger homes may need two suction points.

Recommended

Sub-Slab Depressurization (SSD)

Older home near Crabapple or Downtown Alpharetta

Foundation: Crawl space

Membrane installation adds cost but also reduces moisture. Important for Alpharetta's clay soils that retain moisture.

Recommended

Sub-Membrane Depressurization (SMD)

Luxury estate near Milton border

Foundation: Basement or combination

Larger footprint homes (4,000-6,000+ sq ft) typically need 2-3 suction points. Aesthetic routing is important in high-end homes.

Recommended

SSD or Multi-Point

New construction with RRNC prep

Foundation: Any

If a passive radon pipe was installed during construction, simply adding a fan converts it to an active system. Cost: $300-$500.

Recommended

Fan activation

System Components

Suction Point

A 4-5 inch hole cored through the slab or a pipe inserted beneath the membrane. This is where radon gas is captured.

PVC Vent Pipe

3-4 inch PVC pipe routes from the suction point to above the roofline. Can run through interior walls, garage, or along the exterior.

Radon Fan

Continuously running inline fan rated for radon use. Typically mounted in the attic, garage, or on the exterior near the roofline. Draws 60-90 watts.

Manometer

A U-tube pressure gauge installed on the pipe that provides visual confirmation the system is creating proper suction. Check this monthly.

Sealant/Caulk

Polyurethane caulk seals major foundation cracks, gaps around pipes, and sump pit covers to maximize depressurization effectiveness.

Exhaust Point

The vent pipe terminates above the roofline, at least 10 feet from windows and air intakes, and 12 inches above the roof surface.

Aesthetic Considerations for Alpharetta Homes

In Alpharetta's planned communities and upscale neighborhoods, the appearance of a mitigation system matters. Here's how we minimize visual impact:

Pipe Routing Options

Interior routing: Through closets, utility rooms, and walls to the attic. Most discreet option, preferred for front-facing aesthetics.
Garage routing: Up through the garage to the attic. Common in Alpharetta where most homes have attached garages.
Exterior routing: Along a side or rear wall. Fastest installation, pipe can be painted to match siding.

HOA Considerations

Approval: Most Alpharetta HOAs allow radon systems as health and safety installations, but check your covenants for exterior modification rules.
Placement: We prioritize routing on the least visible side of the home, often the rear or garage side.
Finish: Exterior pipes can be painted to match your home's trim or siding color for a clean look.

Multi-Point Systems for Larger Homes

Many Alpharetta homes are 3,000 to 6,000+ square feet. For larger homes, a single suction point may not create adequate negative pressure across the entire foundation. Here's a general guide:

Home Size (Slab Area)	Typical Suction Points	Estimated Cost
Under 2,500 sq ft	1 point	$1,000 - $1,500
2,500 - 4,000 sq ft	1-2 points	$1,200 - $1,800
4,000 - 6,000 sq ft	2-3 points	$1,500 - $2,500
6,000+ sq ft	3+ points	$2,000 - $3,500+

Exact requirements depend on sub-slab aggregate, soil type, and foundation layout. A diagnostic test during assessment determines the optimal configuration.

Mitigation System FAQs

What is the best radon mitigation system for Alpharetta homes?

For most Alpharetta homes, sub-slab depressurization (SSD) is the best option. Since the majority of Alpharetta's housing stock is slab-on-grade construction, SSD is the most effective and most commonly installed system. For older homes with crawl spaces, sub-membrane depressurization (SMD) is the standard approach.

How does a radon mitigation system work?

All active radon mitigation systems work on the same principle: a continuously running fan creates negative pressure beneath your foundation, intercepting radon gas before it enters your home. The gas is drawn through a PVC pipe and exhausted above the roofline where it disperses harmlessly into outdoor air.

How long does installation take in Alpharetta?

Most single-system installations (SSD or SMD) are completed in 4 to 8 hours, a single day. Multi-point systems for combination foundations or very large homes may take 1 to 2 days. You can stay in your home during installation.

Will the system be visible on my home?

The vent pipe is the most visible component. It can be routed through interior walls (least visible), through the garage (common in Alpharetta), or along an exterior wall. For HOA-regulated Alpharetta communities, we work to route pipes on the least visible side of the home and can paint the pipe to match your exterior.

How loud is a radon fan?

Modern radon fans are designed for quiet operation. Most produce a low hum similar to a bathroom exhaust fan. When mounted in the attic, the sound is virtually unnoticeable inside the home. Exterior-mounted fans may produce slight noise near the installation point.

How do I know if my system is working?

Every system includes a manometer (U-tube pressure gauge) on the vent pipe. The liquid levels should be uneven when the fan is running, indicating active suction. Check this monthly. We also perform a post-installation radon test to verify levels have dropped below 4.0 pCi/L, typically well below 2.0 pCi/L.

Do larger Alpharetta homes need multiple suction points?

Homes over approximately 2,500 square feet of slab area may benefit from two suction points. Homes over 4,000 square feet often need two or three. This ensures the pressure field extends across the entire foundation. Our site assessment determines the optimal number of suction points for your specific home.

How long do radon mitigation systems last?

The PVC pipe and structural components last indefinitely. The radon fan typically lasts 5 to 10 years before needing replacement ($300-$600 installed). There are no filters to change or moving parts other than the fan motor. The system runs 24/7 with minimal maintenance.