Add a Drainage System Under Raised Decks

Covered patio with outdoor furniture and ceiling fan under a raised deck.

A drainage system under a raised deck channels water away from your deck to create a dry, usable area underneath for storage or additional living space. This guide will walk you through adding an under-deck drainage system, from understanding the need for such a system to installation and maintenance.

Types of Under-Deck Drainage Systems

Several under-deck drainage systems are available, each with its advantages. The three main types are EPDM rubber panels, interlocking vinyl panels, and coated steel or aluminum panels. Let’s explore each option in detail.

EPDM Rubber Panels

EPDM (Ethylene Propylene Diene Monomer) rubber panels are popular for under-deck drainage systems. These panels are known for their durability and resistance to various environmental factors.

EPDM rubber panels are flexible and easy to install, making them a good option for do-it-yourself enthusiasts. They create a waterproof barrier that effectively channels water away from the underside of your deck. However, these systems typically require the addition of a separate gutter and ceiling to conceal the drainage system.

Interlocking Vinyl Panels

Interlocking vinyl panels offer a two-in-one solution for under-deck drainage. These panels create a water-diverting system and provide a finished ceiling appearance. Vinyl panels are generally easy to install and maintain but may be more susceptible to heat and high winds than other materials.

Coated-Steel or Aluminum Panels

Coated steel or aluminum panels offer superior strength and heat resistance for those seeking a more robust solution. These panels are typically hung from under-joist supports, creating an attractive ceiling while effectively channeling water away from the deck.

While metal systems often require professional installation, there are do-it-yourself options available.

DIY Installation Guide for Under-Deck Drainage Systems

Before you begin, assess your deck, choose the right system, and gather the necessary tools and materials. Here’s a step-by-step guide to help you through the process.

Assessing Your Deck

Before installing an under-deck drainage system, carefully inspect your deck to ensure it’s in good condition and suitable for the addition. Check for any signs of damage or rot in the joists, beams, and support posts. If you’re planning to install composite decking, now might also be a good time to consider that upgrade. Measure the area beneath your deck to determine the material needed for your drainage system.

Tools and Materials Needed

Gather all necessary tools and materials before beginning the installation. Common tools include:

Materials will vary depending on the system you choose, but typically include:

Drainage panels and troughs
Support tracks or hangers
Screws and fasteners
Gutters and downspouts
Sealant or caulk

General Installation Process

While the specific installation steps will vary based on the system you choose, here’s a general outline of the process:

Clean and prepare the area beneath your deck.
Install support tracks or hangers along the deck joists.
Attach the drainage panels or troughs to the supports, ensuring proper slope for water runoff.
Install gutters along the low end of the slope.
Connect downspouts to direct water away from the foundation.
Apply sealant or caulk as needed to ensure a watertight system.
If applicable, install the finished ceiling panels.

Always follow the manufacturer’s instructions carefully, as each system may have specific requirements or techniques for optimal installation.

Professional vs. DIY Installation of Under-Deck Drainage Systems

Homeowners can hire a professional or take on the project themselves. Both approaches have advantages and disadvantages, and the best choice depends on various factors, including your skill level, available time, and budget.

Pros and Cons of Professional Installation

Professional installation offers several benefits:

Expertise and experience
Time savings
Guaranteed quality of work
Access to specialized tools and equipment

However, professional installation also comes with some drawbacks:

Higher cost
Scheduling constraints
Less control over the project

When To Consider Do-It-Yourself Installation

DIY installation can be a good option if:

You have experience with similar home improvement projects
You’re comfortable working with tools and following detailed instructions
You want to save money on labor costs
You have the time to dedicate to the project

However, DIY installation may not be suitable if:

You lack the necessary skills or tools
Your deck has complex features or requires extensive modifications
You’re short on time or patience for a potentially challenging project

Before deciding to build your deck or install a drainage system, carefully assess your abilities and the project requirements.

Maintenance and Care for Under-Deck Drainage Systems

Proper care will help prevent clogs, leaks, and other issues that could compromise the performance of your under-deck drainage system.

Regular Cleaning Tips

Keep your drainage system clean by:

Removing debris from gutters and downspouts regularly
Flushing the system with water to clear any buildup
Inspecting panels or troughs for any accumulated dirt or leaves
Cleaning the finished ceiling surface according to manufacturer recommendations

Seasonal Maintenance Checklist

Perform these tasks seasonally to keep your system in top condition:

Spring: Check for winter damage such as wood splitting, warping deck boards, and mold or mildew growth
Summer: Inspect for any UV damage or heat-related issues like wood cupping, discoloration, and loosening fasteners
Fall: Clear fallen leaves and prepare for winter by checking for loose boards, screws, or nails, and consider applying a weather-resistant sealant
Winter: Monitor for ice dams and remove snow buildup when possible

Cost Considerations of Under-Deck Drainage Systems

The cost of installing an under-deck drainage system can vary widely depending on the type of system, the size of your deck, and whether you choose professional installation or do it yourself.

Pricing for Different Systems

Costs:

EPDM rubber panels: $4.50–$14 per square foot
Interlocking vinyl panels: $5–$13 per square foot
Coated-steel or aluminum panels: $4–$16 to $3–$18 per square foot

Additional Expenses To Consider

When budgeting for your project, don’t forget to account for:

Tools and additional materials (if do-it-yourself)
Gutters and downspouts
Finishing materials for the ceiling (if not included in the system)
Professional installation fees (if applicable)
Permits (if required by your local authorities)

Our Conclusion

Adding a drainage system under your raised deck is a wise investment to enhance your outdoor living space while protecting its structure. Whether you choose EPDM rubber panels, interlocking vinyl panels, coated steel, or aluminum panels, each system offers unique benefits to suit different needs and budgets.

For those comfortable with do-it-yourself projects, installing an under-deck drainage system can be a rewarding experience that saves labor costs. However, professional installation may be worth considering for complex projects, especially if you value the peace of mind that comes with expert workmanship.