Deck Waterproofing in Eugene, Oregon
Membrane systems and under-deck drainage that keep water out of your framing and out of the space below your deck.
Keeping Water Away From the Structure
Eugene gets a lot of rain, and a deck that isn't waterproofed correctly will eventually let water reach the framing underneath. Once that happens, rot sets in even if the visible surface still looks fine. Waterproofing addresses this before it becomes a structural repair.
We install waterproofing membranes on deck surfaces and, for raised decks, under-deck drainage systems that capture water on the underside of the decking and channel it away, so the space below stays dry and usable.
Raised decks are especially common on Eugene homes built on sloped lots, and the space underneath often ends up used as a covered patio, storage area, or parking spot. Without a proper drainage system, that space stays wet for days after every rain, which is both a nuisance and a slow-moving source of structural damage.
Deck Waterproofing Options
Deck Surface Membrane Systems
A waterproof membrane applied to the deck surface to stop water from reaching the boards and framing beneath, typically used on low-slope or roof-deck style surfaces.
Under-Deck Drainage Systems
A drainage panel system installed under a raised deck that channels water off the underside and away from the structure, creating a dry area below suitable for a patio or storage.
Waterproofing Over Living Spaces
Membrane systems rated for decks built above a room, garage or other enclosed space, where a waterproofing failure can cause interior damage rather than just outdoor deterioration.
Seam & Board Gap Sealing
Sealant applied at board joints and seams where water most commonly finds its way into the structure, one of the most overlooked waterproofing details.
Membrane Repair
Damaged or failing waterproof membranes repaired or replaced before water damage spreads into the framing below.
Waterproofing Inspections
An inspection to check whether an existing waterproofing system is still doing its job, useful before buying a home with a raised deck or after noticing early warning signs.
Gutter & Drainage Channel Installation
Gutters mounted under the deck framing to catch and direct water from an under-deck drainage system toward a downspout, keeping it away from the foundation.
Flashing Repair
Flashing at the ledger board and other transition points repaired or replaced, since failed flashing is one of the most common sources of hidden water intrusion.
Ceiling & Soffit Finishing
For finished under-deck spaces, a ceiling panel system installed beneath the drainage layer to create a usable, dry-looking covered area.
How an Under-Deck Drainage System Works
Trough Installation
Sloped drainage panels or troughs are installed under the deck joists to catch water as it passes through the gaps between boards.
Water Channeling
The panels direct water toward a gutter system running along the low side of the deck.
Gutter & Downspout
Collected water flows into a gutter and out through a downspout, away from the house foundation.
Dry Space Below
The area underneath the deck stays dry during rain, making it usable as a patio, storage area or parking space.
What Deck Waterproofing Cost Depends On
- The square footage of the deck surface or under-deck area
- Whether you need surface membrane waterproofing, under-deck drainage, or both
- Deck height and how easy the underside is to access
- Whether the deck sits over a living space, which requires a higher-rated system
- Whether gutters, downspouts or a finished ceiling are part of the scope
Waterproofing is one of those services where doing it right the first time matters more than the upfront price, since a failed system means repeating the structural repair it was meant to prevent. We'll walk you through the right level of system for your deck rather than defaulting to the most expensive option.
Signs Your Deck's Waterproofing Has Failed
Standing Water on the Deck
Water that pools instead of draining off the surface signals a waterproofing or slope problem.
Mold or Mildew Underneath
Mold growing on the underside of a deck usually means moisture is getting trapped there.
Rot in the Framing
Soft or rotted joists are often the end result of water that's been getting past the waterproofing for a while.
Water Stains Below the Deck
Staining or dripping on a ceiling or patio below the deck points to a membrane that needs attention.
Protect Your Deck From Oregon Rain
Call now to schedule a waterproofing inspection for your deck.
Deck Waterproofing Questions
What is under-deck waterproofing?
Under-deck waterproofing is a drainage system installed beneath a raised deck that channels water off the underside of the decking and away from the structure, keeping the space underneath dry enough to use as a patio, storage area, or covered living space.
What should I put under my deck to stop moisture problems?
The right fix depends on the deck's height and how the space underneath is used. Options range from a membrane waterproofing system applied to the deck's underside to a full under-deck drainage panel system that captures and redirects water. We'll recommend the right option after inspecting your deck.
Can you waterproof a deck built over a living space?
Yes. Decks built over a room, garage or basement need a waterproofing membrane rated for that application so water doesn't reach the structure below. This is one of the more critical waterproofing jobs since a failure can cause interior damage.
How do I know if my deck's waterproofing has failed?
Signs include water stains or dripping on the ceiling below a deck, standing water on the deck surface after rain, and soft or damp framing. If you notice any of these, it's worth having the waterproofing inspected before the damage spreads.
Can I use the space under my raised deck once it's waterproofed?
Yes, that's one of the main reasons homeowners install an under-deck drainage system. Once water is being captured and channeled away, the area below stays dry enough to use as a covered patio, storage space or parking area.
How long does an under-deck drainage system last?
A properly installed drainage system is a long-term addition to the deck, though gutters and downspouts should be checked periodically for debris buildup, and the system should be inspected if you notice water bypassing it during heavy rain.