Why Strata Roofs Are a Different Animal

Before Johnny and I started Dads Roofing in 2021, we spent years as Red Seal Journeyman Boilermakers in the Alberta oil sands. That background taught us systems thinking -- how one failure cascades into ten others if you do not catch it early. When we moved to Agassiz and started roofing full-time in the Fraser Valley, we quickly realized that strata buildings are the closest thing to industrial systems in residential work.

A single-family home has one ridge, a few valleys, maybe a chimney. A 40-unit townhouse complex in Chilliwack has dozens of ridges, shared walls between every unit, penetrations for bathroom fans and range hoods on every roofline, and drainage paths that cross property boundaries. One blocked gutter on unit 12 can send water into unit 14's ceiling. One poorly flashed wall-to-roof junction can rot the sheathing behind three units before anyone notices.

After completing over 500 roofs -- including multi-unit strata projects from Hope all the way to Abbotsford -- here are the six problems we see on virtually every strata job.

Problem 1: Deferred Maintenance That Doubles the Final Bill

This is the single most expensive mistake strata councils make, and we see it on at least half the complexes we inspect. The depreciation report says "replace roof in 5 years," but the council pushes it to 8, then 10, then 12. By the time they call us, the shingles are beyond curling -- they are cracking apart, and the decking underneath has started to rot from years of slow water intrusion.

We worked on a townhouse complex in Chilliwack last year where the original roof was installed in 2001. The depreciation report recommended replacement by 2023. The council waited until 2025 because they did not want to levy. By the time we tore off the old shingles, we found rotted plywood on 30% of the deck. What would have been a $180,000 re-roof became a $290,000 project with deck replacement and interior remediation for six units.

How to Avoid This

• Start planning three years before the depreciation report deadline. Get quotes at year four. Schedule work at year five.
• Fund the Contingency Reserve Fund (CRF) properly. A well-funded CRF means no special levy panic.
• Get an annual inspection. A $500-$1,500 inspection catches problems when they are $2,000 fixes instead of $50,000 emergencies.

Problem 2: Valley and Flashing Failures

Strata buildings have two to three times more flashing than a single-family home. Every shared wall has a wall-to-roof junction. Every unit has at least one plumbing vent, one bathroom exhaust penetration, and often a range hood vent. The more penetrations, the more potential leak points.

In Abbotsford, we inspected a complex where four different contractors had done repairs over five years. Each one patched the visible shingle damage but none of them pulled up the flashing to check what was underneath. When we finally stripped the section, the step flashing behind the shared wall was completely corroded -- the original galvanized steel had failed after 22 years of Fraser Valley rain. The water had been running behind the flashing, down the wall sheathing, and into the wall cavity for years.

What We Do Differently

• We trace the full water path. Every leak inspection includes pulling up flashing to check the substrate, not just sealing the surface.
• We use aluminum or painted steel flashing instead of galvanized, which corrodes faster in our high-moisture climate.
• We flash to code and beyond. BC Building Code minimum is 4-inch flashing overlap. We use 6-inch wherever space allows, because strata buildings see higher water volumes at junctions.

Problem 3: Moss and Organic Growth

The Fraser Valley is moss country. Our combination of mild winters, heavy rainfall, and mature tree canopy means every north-facing roof slope turns green within three to five years. Strata complexes are worse because buildings shade each other, tree-lined common areas block sunlight, and maintenance budgets rarely include regular moss treatment.

Moss does real structural damage. The root system grows under shingle edges, lifting them and creating channels for water. We have pulled shingles off Harrison townhouses where the moss roots had grown completely through the shingle mat, turning what should have been a 30-year roof into a 15-year roof.

Our Recommendation

• Professional soft-wash every 2-3 years. Never pressure wash -- it strips granules and voids manufacturer warranties. Budget $1-2 per square foot.
• Install zinc strips at the ridge during your next re-roof. Zinc ions wash down with rain and inhibit moss growth. Cost is $250-$550 per building -- a fraction of repeated cleaning.
• Trim trees within 6 feet of the roofline. More sunlight means less moss. This alone can cut moss growth in half.
• Specify algae-resistant shingles when replacing. The copper granule technology adds $50-$100 per square but significantly reduces organic growth.

Problem 4: Ventilation Deficiencies and Attic Condensation

This is the hidden problem. You cannot see it from the ground, and most strata councils do not think about it until mold shows up on a resident's ceiling. Strata buildings generate far more interior moisture than single-family homes because you have multiple kitchens, multiple bathrooms, and multiple dryers all pushing warm, humid air upward.

We inspected a 1990s-era complex in Chilliwack where every bathroom fan was vented into the attic instead of through the roof. Twenty units, twenty exhaust fans, all dumping steam directly onto the underside of the roof sheathing. The attic had visible mold on every rafter, and the plywood was starting to delaminate. The original builder cut costs by not running the exhaust ducts through the roof -- a shortcut that created a $60,000 remediation project 25 years later.

What Proper Ventilation Looks Like

• 1:300 ventilation ratio minimum. For every 300 square feet of attic floor, you need 1 square foot of net free ventilation area, split evenly between intake (soffits) and exhaust (ridge).
• All exhaust fans must vent to exterior. This is code, but older buildings often do not comply. Retrofitting costs $200-$400 per fan but prevents thousands in mold damage.
• Rafter baffles at every bay. When insulation is added or upgraded, baffles keep the airflow channel open between the soffit and the ridge.
• Continuous ridge vent instead of spot vents. Ridge vents provide even exhaust across the entire roofline, eliminating hot spots and dead zones.

Problem 5: Drainage Failures During Atmospheric Rivers

The Fraser Valley gets atmospheric river events every November and December that dump more rain in 48 hours than some cities see in a month. Strata buildings with complex roof geometry -- multiple valleys, shared gutters, low-slope transition sections -- are especially vulnerable because every drainage path has to handle extreme volumes.

We responded to an emergency call from an Abbotsford strata during the November 2024 storms. Three units had water pouring through their ceilings. The roof was only 12 years old and in decent condition. The problem was a single clogged gutter downspout at the junction of two roof sections. Water backed up, overflowed into the soffit, ran along the ceiling joists, and found its way into three different units. A $200 gutter cleaning would have prevented $15,000 in damage.

Drainage Checklist for Strata Councils

• Clean gutters twice per year minimum -- once in late spring after pollen and blossoms, once in late fall after leaf drop. Complexes with heavy tree coverage may need three cleanings.
• Upgrade to 6-inch gutters if your complex still has 5-inch. The 44% increase in volume capacity makes a real difference during atmospheric rivers.
• Add downspout extensions to direct water at least 6 feet from foundations. Strata buildings often have downspouts dumping water right at the foundation wall.
• Check for ponding after every major rain event. Any standing water 48 hours after rain indicates a slope problem that needs correction.

Problem 6: Unauthorized Unit Owner Modifications

This one catches councils off guard. A unit owner installs a satellite dish, drills through the roof membrane, and does not tell anyone. Another owner hires a handyman to add a bathroom vent through the roof with no proper flashing. A third owner mounts solar panels without council approval. Every one of these penetrations is a potential leak point, and every one voids any existing roof warranty.

We have encountered this on complexes across the Fraser Valley. The most common one is bathroom exhaust fans. An owner upgrades their bathroom, the contractor punches a new hole through the roof for the exhaust, and three years later the strata is dealing with a leak at that exact location. The owner claims it is a strata responsibility because it is on the common property roof. The strata has no record of the modification.

How Councils Can Prevent This

• Bylaw requiring council approval for any roof penetration. Make it clear in the strata bylaws that unauthorized modifications will be reversed at the owner's expense.
• Annual roof inspection. A professional inspection catches unauthorized work. We flag every penetration and note whether it was properly flashed.
• Require licensed contractors only. If council approves a modification, require that a licensed roofer does the penetration and flashing work.

The Pattern Behind Every Problem

After working on hundreds of strata roofs, Johnny and I have noticed that every one of these six problems comes back to the same root cause: information gaps. Councils do not know the condition of their roof. They do not know what their depreciation report actually recommends. They do not know that their ventilation is undersized or that a unit owner drilled through the membrane last summer.

The single best investment any strata council can make is a thorough annual inspection with a written report and photos. It costs $500-$1,500 depending on the size of the complex. It gives the council hard data to make decisions with instead of guessing. And it catches every one of these six problems before they turn into emergencies.

Dads Roofing works with strata councils across the Fraser Valley -- from Hope to Abbotsford and everywhere in between. We provide detailed inspection reports, honest assessments, and workmanship backed by 500+ completed roofs. If your council is dealing with any of these problems, or just wants to get ahead of them, give us a call.

Frequently Asked Questions

Strata council dealing with roofing issues? Call (778) 539-6917 or email info@dadsroofrepair.com for a strata roof inspection.