The space beneath your deck shouldn’t be wasted. Premier Deck Builders installs integrated underdeck waterproofing systems that capture rainwater, protect your framing from moisture, and turn the area under your deck into dry, usable square footage.
As your local decking contractor, we construct structurally sound, code-compliant decks with built-in water control, designed explicitly for Michigan’s weather conditions and backed by precision installation.
Why Underdeck Waterproofing Matters in Michigan
Without drainage, second-story decks create constant problems underneath. Michigan snowmelt, spring rain, and freeze-thaw cycles lead to rot, staining, splash zones, and mildew growth.
Our waterproofing systems prevent that by:
- Capturing runoff between or over joists
- Directing water into sealed downspouts
- Creating a dry zone beneath the structure, ready for storage, relaxation, or future upgrades
We install these solutions during new deck construction or significant renovations, ensuring long-term performance and a clean, dry result.
What We Install and How It Works
We utilize two primary systems designed for different project types and goals.
DrySpace (Joist-Mounted Drainage)
DrySpace is a rigid vinyl panel system installed between joists underneath the decking surface. Designed for retrofit or existing deck projects, it collects runoff and redirects it to a perimeter gutter.
- Installs between open joists after framing
- Made from solid extruded vinyl—resists sagging, UV, and cracking
- Redirects water into integrated gutters
- Available in White or Bone for a clean, ceiling-like finish
- Requires a second-story elevation to allow slope for drainage
Unlike fabric or open-channel solutions, DrySpace is engineered to withstand downpours without pooling or overflow, making it ideal for Michigan’s heaviest rain events.
Learn more about TimberTech DrySpace.
Over-Joist Waterproofing (RainEscape-Type)
Over-joist systems are designed for new construction and rebuilds. They are installed over the framing before any deck boards are laid down and create a top-down waterproof barrier that keeps the framing dry and provides a fully protected space below.
- Installed directly over joists before decking
- Made of durable polyethylene troughs and flashings
- Fully shields structural framing from above
- Compatible with recessed lighting, ceiling fans, and full underdeck finishes
- Ideal for finished outdoor rooms, entertainment zones, or all-season patios
This is the only method that protects the underdeck area and the framing itself, making it a foundational part of long-term deck performance.
Benefits of Underdeck Waterproofing
Adding a drainage system does more than stop drips. It changes how your deck functions and what you can do beneath it.
- Protects Framing: Extends the life of joists, beams, and hardware by eliminating trapped moisture
- Creates Dry, Usable Space: Turn unused ground into shaded patios, dry storage, or enclosed rooms
- Supports Comfort Upgrades: Add fans, lighting, or speakers below without electrical risk
- Improves Drainage: No more muddy splash zones, rot stains, or ceiling drips
- Reduces Maintenance: No scrubbing mildew or sealing joist ends every season.
- Increases Home Value: Adds functional square footage and clean visual appeal
- Storm-Resilient Use: You can still enjoy the space under your deck, even during heavy rain
- Future-Ready: Once waterproofed, the space is ready for future enclosures, shade structures, or screen rooms
How We Build It Right
We don’t bolt on a drainage kit—we design and install it as part of your deck’s structural system.
1. Site Walk + Drainage Plan
- Evaluate elevation, pitch, and runoff flow.
- Check joist access and determine retrofit limits or new build specs.
2. System Selection
- Choose between DrySpace or over-joist membrane systems.
- Confirm slope tolerances and downspout discharge locations.
3. Installation
- Joist-mounted systems are added post-framing.
- Over-joist systems are installed before the boards are laid down.
- Panels are sealed, sloped, and checked for proper flow.
4. Gutter + Downspout Integration
- Direct water to a clean runoff zone, dry well, or daylight outlet.
- Include extensions where site grading requires it.
5. Optional Add-Ons
- Pre-frame for ceiling fans, lighting chases, or soffits.
- Fully finish the ceiling beneath for a polished look.
We install each system to the manufacturer’s technical standards, ensuring your waterproofing performs as intended and your warranty remains valid.
Why Choose Our Waterproof Deck Systems?
- Superior Craftsmanship: We treat every build as our own, from slope planning to gutter alignment, ensuring every waterproofing system performs under pressure.
- Durable, High-Quality Materials: We utilize field-tested components, including extruded vinyl, HDPE membranes, and corrosion-resistant fasteners, specifically designed to withstand Michigan’s moisture and freeze-thaw cycles.
- Tailored to Your Deck: Every system matches your deck’s elevation, framing style, and runoff conditions for adequate drainage, not just a visually appealing design on paper.
- Efficient Installation: Most underdeck waterproofing installations are completed within a few days and integrated into the build with minimal disruption.
- Licensed and insured: We handle all permits, inspections, and code requirements. There are no gaps or guesswork—just clean, compliant work from start to finish.
Every waterproofing system is backed by our 3-year craftsmanship warranty and is built for Michigan weather, from the spring thaw to the winter freeze.
Our Commitment to Quality
We take pride in building smart, not fast. From the joist spacing to the gutter pitch, every detail matters—and every system we install is built to last.
- Westbury Certified Master Pro Installer
- TimberTech Platinum Pro
- NADRA Member (North American Deck & Railing Association)
- Licensed through Michigan LARA
- Proud Member of the Chamber of Commerce
Where We Install Underdeck Waterproofing
We serve homeowners across the Greater Ann Arbor, MI area, including: Ann Arbor, MI, Saline, Ypsilanti, Milan, Chelsea, Dexter, Pittsfield Township, Tecumseh, and Manchester.
Don’t see your city? Call us. We’ll review it to see if it fits our scope and schedule.
Ready to Build a Better Deck—From the Bottom Up?
A second-story deck shouldn’t cause problems below. With underdeck waterproofing from Premier Deck Builders, you’ll protect your structure, extend your living space, and reduce long-term maintenance, built by contractors who understand what works in Michigan.
Get your free estimate today and speak with a waterproofing contractor who builds smarter, drier outdoor spaces.
