Roofing & Building Exterior
Waterproofing
Membranes, sealants and detailing for balconies, below-grade walls and building joints – planned and installed to keep water out of the structure.
Overview
Water finds every gap. Balconies and elevated decks over living space, planters, elevator pits, retaining walls and the joints around windows and doors are the places where buildings most often let water in. Good waterproofing is mostly about planning: slope, transitions, terminations and drainage are designed before a membrane is applied.
We plan and supervise waterproofing performed by specialist waterproofing trade partners, using systems installed to the manufacturer’s published requirements. We pay close attention to the details where systems meet – door thresholds, wall-to-deck transitions, drains and penetrations – and test before finishes go on, because waterproofing is far easier to fix before it is covered with tile or pavers.
This page covers planned waterproofing in new construction and renovation. If water is already getting in, the source has to be found first; that work is handled as an assessment-based water intrusion repair.
Who it’s for
- Homes with balconies, terraces or decks over conditioned space
- Buildings with below-grade or earth-retaining walls, elevator pits or planters
- Renovations replacing balcony tile, pavers or coatings
- Commercial and multifamily buildings needing joint sealant replacement
- New construction where waterproofing details are part of the exterior envelope
What’s included
Typically included
- Review of drawings and existing conditions to identify waterproofing areas and transitions
- Surface preparation, including cleaning, crack treatment and slope correction where required
- Balcony and deck membranes – liquid-applied, sheet or under-tile systems
- Flashing and detailing at door thresholds, walls, drains, railings and penetrations
- Below-grade waterproofing on retaining walls, stem walls, elevator pits and planters
- Drainage boards and protection layers where specified
- Sealant replacement at windows, doors, control joints and expansion joints
- Flood or water testing of horizontal membranes before finishes are installed
- Coordination with tile, paver and railing trades that install over or through the membrane
Common exclusions
- Finding the source of active leaks, which is handled as water intrusion repair
- Structural concrete repair, such as spalling balconies, which needs an engineer’s assessment
- Roofing systems, installed by a licensed roofing contractor
- Finish materials over the membrane, such as tile or pavers, unless included
- Mold remediation
Every proposal lists its own inclusions and exclusions in writing.
Materials, design options & upgrades
How pricing works
Waterproofing is normally priced by the square foot of area treated, with linear items such as joints and flashings counted separately. An estimate is built from measured areas, the selected system, existing conditions and the number of transitions and penetrations.
For renovations, removing existing finishes often reveals conditions that change the scope, so estimates may include unit prices for slope correction or substrate repair.
What changes the cost
- Area and the waterproofing system specified
- Removal of existing tile, pavers or coatings
- Substrate condition, cracks and slope correction
- Number of transitions, drains and penetrations
- Access – upper-level balconies and occupied buildings
- Testing requirements
If this work is part of a larger project, it’s priced within that project’s budget — please don’t add separate estimates together. Read the pricing guide.
Typical stages
Survey and plan
We review the areas, the drawings and existing conditions, and define the system and details.
Prepare
Existing finishes are removed where needed, surfaces are cleaned and repaired, and slope is corrected.
Detail
Transitions, drains, thresholds and penetrations are flashed and reinforced first.
Apply membrane
The field membrane or below-grade system is installed to the manufacturer’s requirements.
Test
Horizontal areas are flood-tested where practical before finishes go on.
Protect and finish
Protection layers are installed and finishes are coordinated over the membrane.
What affects the schedule
- Most membranes need dry surfaces and suitable temperature and humidity to cure
- Rain interrupts application, especially in the wet season
- Testing must be complete before tile, pavers or backfill
- Doors and railings may need to be removed and reinstalled in sequence
Questions & answers
Why does my balcony leak even though the tile looks fine?
Tile and grout are not waterproof. Water passes through to whatever lies beneath. If the membrane below is missing, damaged or not properly detailed at the door and edges, leaks can show up inside even when the surface looks intact.
Do Florida homes need below-grade waterproofing?
Basements are uncommon, but stem walls, retaining walls, elevator pits and planters are all earth-contact walls that can benefit from it, particularly where groundwater is high.
How often should sealants be replaced?
Sealants degrade with sun and movement. Inspect them regularly and replace them when they crack, harden or pull away. The right interval depends on the product and exposure.
Start here
Planning waterproofing?
A short form — three steps, a few minutes. Share plans or photos if you have them. We’ll review it and follow up using the contact details you provide.