November 18, 2025

What to Do When Your Stucco Starts Peeling or Bulging

Stucco should sit flat, shed water, and hold steady through Edmonton’s freeze-thaw cycles. When it starts peeling, bulging, or blistering, the wall is telling a story. Sometimes the message is simple: a failed paint film or a hairline crack that let water in. Other times, the issue points to trapped moisture, delamination, or a compromised moisture barrier. Acting early protects framing, insulation, and indoor air quality — and avoids a full wall rebuild.

This guide explains how to spot the cause, what a safe repair looks like in Edmonton’s climate, and when to bring in a local specialist. It draws on field experience with stucco repair in Edmonton neighborhoods from Glenora and Allendale to Terwillegar and Mill Woods, where sun, wind, and wide temperature swings stress every exterior.

What peeling and bulging actually mean

Peeling describes the finish coat or paint film lifting from the base. It looks flaky or scaly. A putty knife often lifts sheets of paint or thin finish with little force. This usually points to poor adhesion, vapor pressure from behind the coating, or chalky substrate.

Bulging means the stucco plane swells out. It often sounds hollow when tapped. The base coat may have separated from the lath, or the lath has pulled away from the sheathing. In both cases, the bond is failing. Bulging can follow long-term moisture intrusion, freeze-thaw damage, or missing expansion joints.

A third sign often shows up with both: staining. Brown or rust streaks under window corners or at mid-wall can mark water paths. Efflorescence — a white, powdery bloom — suggests moisture moving through the stucco and depositing salts as it evaporates. These clues help narrow the root cause.

Why stucco fails in Edmonton

Edmonton’s climate sets strict rules. Winter brings deep cold and dry wind. Spring adds rapid melt. Summer delivers high UV and heavy downpours. These cycles drive expansion and contraction. If a system was installed without proper control joints, sealants, or drainage, stress concentrates in certain spots. Water finds those points.

Typical triggers seen during stucco repair in Edmonton include: paint with low vapor permeability trapping moisture behind it; aging sealants around windows that have shrunk away; missing kick-out flashing at roof-to-wall transitions that dump water into the wall; stucco applied over damp sheathing in fast-track builds; and stucco thickness below spec on lath, which compromises strength.

Wood framing and OSB sheathing do not tolerate long exposure to trapped moisture. If the moisture barrier is punctured and the lath fasteners corrode, the system loses its anchor and bulges. In older homes with single paper weather barriers, wind-driven rain can work through small defects and accumulate.

Quick checks a homeowner can do safely

A homeowner can gather useful information without creating more damage. This early information helps a contractor price and plan a focused repair rather than a guess.

Knock test: Tap the bulged area lightly with your knuckles and compare it to a solid area. A hollow, drumlike sound suggests delamination from lath or lath from sheathing.
Moisture look-over: Check interior walls opposite the issue. Look for baseboard swelling, drywall bubbles, or a musty smell. These signs mean moisture has moved past the stucco.
Sealant scan: Inspect window and door perimeters, light fixtures, and meter penetrations. Cracked or missing sealant often lines up with damage below.
Roof-to-wall junctions: Walk the ground and look up. At the bottom of a roof valley where it meets a wall, a small piece of metal called a kick-out flashing should direct water into the gutter. If it is missing, stucco below often shows stains or bulging.
Grade and downspouts: Ensure the grade slopes away from the house. Splash blocks or extensions should carry water at least 1.5 to 2 meters from the foundation. Poor drainage keeps walls damp.

If any of these checks suggest ongoing moisture, pause repainting plans and avoid power washing. Forcing water into a compromised system will worsen the problem.

What a proper diagnosis looks like

A thorough assessment runs deeper than a visual glance. For stucco repair in Edmonton, a dependable process usually includes surface mapping, moisture readings, and small targeted probes. The goal is to define the wet footprint, the failure layer, and the cause.

A technician should start with thermal imaging or pinless moisture scanning to mark anomalous zones. These tools do not diagnose by themselves, but they point to areas that need confirmation. Next, small test cuts at seam lines or hairline cracks allow inspection of the base coat, lath, fasteners, and sheathing. The crew looks for corrosion, blackened sheathing, mold odor, and wet readings in wood. In many cases, a 10 by 10 cm cut reveals the story without scarring the elevation.

Around windows, the team checks head flashing, sill pans (if present), and the condition of the building paper or housewrap. In older assemblies, missing head flashing is common. In newer ones, the paper laps may run the wrong way, allowing water to drain into the opening. Each detail matters. A good contractor documents findings with photos so the repair scope is clear before work starts.

Repair paths based on what the wall tells you

Peeling finish with solid base coat. If the base coat is sound and the hollow test is clean, the fix focuses on surface preparation. The crew removes loose paint and finish, treats chalky areas with a bonding agent compatible with stucco, and uses a breathable coating system. Acrylic elastomerics can bridge hairline cracks, but in Edmonton they must have adequate vapor permeability. Trapped vapor creates blisters during freeze-thaw cycles. Expect prep, patch, and repaint to take one to three days for a typical side elevation, weather permitting.

Localized bulge with intact sheathing. When stucco separates from the lath due to poor bonding, repair means removing the failed area back to a firm edge, retying or replacing lath, and installing new base and finish coats. The crew reinstalls control joints if missing. Color matching matters; natural aging changes hue. A test panel helps select a close blend. This is a mid-size job that often wraps in three to five days.

Bulge with wet or damaged sheathing. This points to water entry. The team opens a larger area to reach dry, clean substrate. They replace compromised OSB or plywood, verify and repair the moisture barrier, and add flashings where needed. Only then do they rebuild the stucco. Skipping the root cause invites a repeat. Timelines range from four days to two weeks based on the size and the need for drying time. During cool months, controlled heat and airflow may be required to dry framing before closing up.

Widespread peeling after repaint. This often follows a low-perm paint over older stucco. The fix may involve mechanical removal of the paint film with careful abrasive methods, followed by a permeable coating system. Spot repairs address any cracks. Expect noticeable dust control and site protection. A professional crew will mask windows, doors, and landscaping, and use HEPA vacuums.

Crack patterns linked to structure. Horizontal cracking near floor lines or stair-step cracks around openings can indicate framing movement. In these cases, repair may include adding or realigning control joints, and then reapplying base and finish. If framing or foundation settlement is active, a structural review is wise before cosmetic work.

Edmonton-specific materials and details that hold up

Success in this climate relies on small choices done consistently. Breathable coatings outperform dense membranes on traditional cement stucco. A high-quality acrylic finish can work well if it lets vapor out. Cement-based finish coats remain a strong option for breathability dependexteriors.com stucco repair Edmonton and texture match on older homes.

Fasteners should be corrosion resistant. Galvanized staples or nails for lath are common, but in areas prone to splash, stainless fasteners reduce future rust stains and hold strength over time. Control joints need to break up large wall expanses. The general rule is to limit panels to about 13 square meters or spans of 5 to 5.5 meters in any direction, but real walls vary. Adding joints around window groupings and long gables prevents stress buildup.

Sealants should be flexible and paintable. High-quality polyurethane or silyl-terminated polyether sealants stand up to UV and movement better than basic silicones. Proper joint design matters: a backer rod sets depth so the sealant can expand and contract. Too deep and it tears; too thin and it fails early.

At roof-to-wall intersections, properly lapped kick-out flashings save walls. This small metal diverter is one of the most cost-effective details in stucco repair in Edmonton because it stops water before it reaches the stucco. Window heads need metal flashing that pushes water out over the face of the stucco, not behind it.

Cost ranges and what drives them

Homeowners often ask for a number by phone, but wall conditions decide the budget. For surface-level peeling with no moisture issues, small repairs and recoating on a single elevation might fall in the low thousands, assuming easy access and a straightforward color match. Localized bulging with lath repair typically lands in the mid-range. Once sheathing replacement, flashing upgrades, and drying time enter the plan, costs climb based on area opened and site constraints.

Scaffolding can influence cost on two-story homes in Westmount or Crestwood with limited driveway access. Winter work requires heat and enclosure to cure properly, which adds time and material. On the other side, combining repairs with a planned repaint can lower total cost because access and protection happen once.

Repair timing through the seasons

Edmonton’s dry cold helps with indoor drying, but exterior stucco work has temperature thresholds. Cement-based coats need suitable temperatures to cure. Crews can work in winter with temporary enclosures and heaters, but the logistics add complexity. Spring and early fall offer the best balance of temperature and humidity. Summer works well but requires careful curing to avoid rapid water loss in the base coat.

Small emergency openings can be protected in any season to stop further water damage. Even a temporary weatherproof patch installed cleanly can buy time until full repair conditions are right. A reputable local contractor will advise when to open walls now versus stabilize and schedule for the next appropriate window.

What not to do

Two shortcuts create repeat failures. The first is painting over blistered or peeling areas without addressing moisture. This hides symptoms for a season, then the bulge returns larger. The second is patching bulges with surface filler. Fillers hold shape briefly but have no anchor to failing lath or wet sheathing. A third avoidable mistake is pressure washing a compromised wall. High-pressure water forces liquid into cracks and behind trim, turning a small problem into a wide one.

Another misstep is mismatched materials. Applying an impermeable elastomeric over a traditional cement stucco that needs to breathe traps vapor and drives peeling. Or using interior-grade sealants around exterior fixtures, which crack under UV and cold.

How Depend Exteriors approaches peeling and bulging

A reliable process beats guesswork. The Depend Exteriors team starts with a focused assessment: surface mapping, moisture checks, and small exploratory cuts where needed. The crew explains findings in plain language with photos, not jargon. The recommended scope aligns with what the wall reveals — no bigger, no smaller.

For projects across Edmonton, Sherwood Park, St. Albert, and nearby communities, the team sets containment to protect windows, plantings, and neighboring properties. They remove only what is necessary and rebuild each layer properly: sheathing if needed, moisture barrier with clean laps and flashings, metal lath installed with correct fasteners and spacing, base coat to required thickness, and a finish that matches existing texture. On repaint projects, they pick breathable coating systems suitable for local stucco assemblies.

Color matching is handled on site with test panels. For homeowners in older neighborhoods like Strathearn and Highlands, texture continuity matters as much as color, so the crew samples and adjusts sand gradation and float technique for a natural blend. The company schedules around season and weather, offers temporary protection when immediate open-up is required, and aims for clear communication throughout.

Small signs that matter more than they seem

A slight soft spot under a second-story window might not look urgent. In practice, these are often the first indicators of a failed sealant joint or missing flashing. A few rust streaks at fastener heads can signal lath corrosion behind the coat. Hairline cracks radiating from a window corner point to stress concentration that can admit water under wind load.

Homeowners who catch and act on these details reduce the scope of repair. Quick attention often turns a likely sheathing replacement into a simpler lath and base patch. In cold months, a temporary, breathable cover over suspect areas can stabilize the wall until the full repair can take place.

Answers to common questions from Edmonton homeowners

Will repainting stop peeling? Repainting helps only if the substrate is sound and dry. If moisture or delamination is present, repainting will fail. The right sequence is diagnose, repair, then select a breathable coating compatible with stucco.

Can bulging be spot-repaired? Yes, if the failure is localized and the surrounding lath and sheathing are solid. The repair must tie into intact lath and include proper bonding at the seams. If moisture has spread, the open area should extend to dry, firm material.

How long should a repair last? With correct details — flashings, control joints, sealants, and a permeable finish — a repair should integrate into the wall and perform for many years. Expect routine sealant maintenance every five to eight years due to UV and movement.

Is EIFS the same as stucco? EIFS is an insulated, synthetic system that behaves differently. Many Edmonton homes have traditional cement stucco. Diagnosis and products differ, so a quick field check helps identify the system. Cement stucco is hard and gritty; EIFS feels slightly softer to the touch and often shows foam in cross-section at penetrations.

What about winter repairs? Emergency stabilization can happen anytime. Full stucco coats can be completed in winter using enclosures and heat, but the plan must respect curing needs. A local crew familiar with cold-weather work can decide case by case.

When to call a professional

Homeowners can spot problems and maintain sealant, but opening walls, handling wet sheathing, and tying in lath and base coats call for trained hands. Safety is also a concern on two-story elevations and icy ground. If there is visible bulging, ongoing peeling after repainting, interior staining, musty odor, or any sign of structural movement, bring in a specialist.

For stucco repair in Edmonton, local experience matters because materials, climate, and common installation histories vary by area and build year. A contractor who has worked across neighborhoods will recognize patterns quickly and zero in on causes.

Ready for a straightforward plan?

Depend Exteriors helps homeowners across Edmonton, St. Albert, and Sherwood Park fix peeling, bulging, and water-damaged stucco with clear diagnostics and durable repairs. The team shows findings, explains options, and restores the wall layer by layer so the issue does not return next spring.

If a wall is peeling or bulging — even slightly — request a site visit. Early action keeps costs down and protects the structure. Call Depend Exteriors or send a photo with your address in Edmonton, AB. A specialist will respond, schedule an assessment, and propose a repair that fits the house, the season, and the budget.

Depend Exteriors – Hail Damage Stucco Repair Experts in Edmonton, AB

Depend Exteriors provides hail damage stucco repair across Edmonton, AB, Canada. We fix cracks, chips, and water damage caused by storms, restoring stucco and EIFS for homes and businesses. Our licensed team handles residential and commercial exterior repairs, including stucco replacement, masonry repair, and siding restoration. Known throughout Alberta for reliability and consistent quality, we complete every project on schedule with lasting results. Whether you’re in West Edmonton, Mill Woods, or Sherwood Park, Depend Exteriors delivers trusted local service for all exterior repair needs.