Commercial Roof Penetration & Curb Installation

Commercial roof penetration installation is the detailed work of cutting, framing, and sealing every opening a roof needs, and it is where a sound roof is most easily compromised. Any time a pipe, vent, conduit, or piece of rooftop equipment passes through the membrane, that opening becomes a potential leak point unless it is detailed correctly.

Markit Roofing installs penetrations and equipment curbs on commercial and industrial roofs across Calgary and Edmonton, ensuring each new opening is framed, flashed, and sealed to the same standards as the roof around it. Whether you are adding an HVAC unit, running new vents or conduit, mounting rooftop equipment, or sealing an existing penetration that has started to fail, we handle the curb framing, membrane termination, boot and flashing detailing, and final weatherproofing as one properly integrated job.

Done well, a penetration disappears into the roof and never troubles you again. Done carelessly, it becomes the exact spot where water finds its way in months later, so our crews treat these transitions as the critical details they are, protecting both the roof’s performance and its warranty.

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Why Penetrations Are the Weak Point

Most commercial roof leaks do not begin in the membrane’s open field. They start at penetrations and curbs, the transitions where the flat surface is interrupted by something passing through it. Every one of these openings breaks the continuous waterproofing and depends entirely on careful detailing to stay sealed. A poorly flashed pipe, an unframed equipment opening, or a curb that was rushed will hold for a while, then fail quietly as the membrane and sealant move with temperature. Getting these details right at installation is far cheaper than chasing the leak they cause later.

What We Install and Detail:

Pipe, vent, and conduit penetrations with properly sealed boots
Equipment curbs for HVAC units, RTUs, and other rooftop plant
Structural framing and support around larger openings
Flashing, counterflashing, and membrane termination at each opening
Resealing or rebuilding existing penetrations that have started to fail

Each of these has to tie cleanly into the surrounding roof system so the waterproofing stays continuous. A curb, for example, is not just a frame to bolt a unit onto; it is a raised, flashed transition that has to shed water and move with the roof. We install and detail every opening to suit your specific membrane, so the new penetration behaves as an integrated part of the roof rather than a patch sitting on top, waiting to leak.

Our Process

Planning the Opening and Its Location

Good penetration work starts before anything is cut, because where and how an opening is placed shapes whether it will ever leak. We assess the roof system, the structure beneath, and the equipment being installed, then plan the opening’s position to work with drainage rather than against it. Placing a curb in a low spot where water pools, or crowding a penetration against a wall or another unit, invites trouble that no amount of sealant fixes later.

We also confirm the structural support needed for the load, especially for heavier rooftop units. This planning stage is where leaks are prevented, long before the membrane is touched. By getting the location, drainage, and support right first, we make sure the detailing that follows protects a sound opening rather than compensates for a badly placed one.

Framing and Structural Support

With the layout set, we build the framing and support the opening requires. For a curb, that means constructing a properly sized, correctly heighted frame that raises the equipment above the roof surface and provides a sound surface for the flashing to terminate against. For larger openings, it means adding the structural support to carry the load and maintain the roof’s integrity around the cut. This stage is invisible once the roof is finished, but it is what everything above depends on.

A curb that is too low, out of level, or poorly supported undermines the waterproofing, however carefully the membrane is later detailed. We frame each opening to the correct dimensions and height for your system and equipment, so the weatherproofing has a solid, stable base and the finished penetration carries its load without stressing the roof.

Membrane Termination and Flashing

This is the detail that determines whether the penetration leaks, so we treat it as the heart of the job. We terminate the roof membrane cleanly at the opening and install the appropriate flashing, boots, and counterflashing to carry water away and seal the transition. For a pipe, that means a properly sized boot bonded and clamped to the membrane. For a curb, it means flashing that wraps and terminates so water sheds off rather than sitting against the joint.

Every material is matched to your specific membrane system, ensuring a sound bond and a valid warranty. These transitions are precisely where careless work fails, so we detail them deliberately, ensuring the seal is continuous and that nothing relies solely on the sealant to keep water out.

Sealing, Testing, and Cleanup

Once the flashing is complete, we finish the seal, confirm the detailing is sound, and make sure the opening is genuinely watertight before we call it done. We check that water will move off and around the penetration correctly, that every termination is bonded and secure, and that no gap has been left, relying on caulking as a last line of defence. Any offcuts, fasteners, and debris from the work are cleared, leaving your roof clean and your equipment sitting on a properly finished base.

We then document the completed penetration or curb for your records, so you have clear proof of how it was installed should a warranty question ever arise later. The finished opening should behave exactly like the rest of the roof, sealed, stable, and forgotten, rather than becoming the spot you find yourself watching every time it rains.

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Why Choose Markit Roofing for This Work

We approach every penetration and curb as the leak risk it genuinely is, not as a quick finishing task tacked onto someone else’s install. Our crews understand that the seal at an opening has to survive years of thermal movement, water, and the load of whatever sits on it, so they detail each transition deliberately rather than relying on sealant to bridge sloppy work. That care is what makes the difference between an opening that disappears into the roof and one that becomes a recurring service call. You are getting people who know these transitions fail first, and who therefore give them the deliberate attention the rest of the trade too often skips over in the rush to finish.

A penetration only stays watertight when its detailing matches the exact membrane it ties into, so we never treat this as one-size-fits-all. We match boots, flashing, and curb detailing to your specific roof system, so the new opening bonds properly and behaves as an integrated part of the roof rather than a foreign patch waiting to lift. Using the right materials and terminations for your membrane is also what keeps the roof warranty intact, since incompatible or improvised detailing is exactly the kind of thing that voids coverage. This system-specific approach means the equipment you add sits on a base built to last as long as the roof beneath it, not one that ages out ahead of everything around it.

Rooftop openings are usually intended to serve equipment, so the roofing work has to align with the mechanical or electrical installation rather than clash with it. We coordinate the curb and penetration work with your equipment schedule, ensuring the opening is framed, sized, and sealed to receive the unit correctly and that the roof is never left open and vulnerable between trades. That coordination prevents the gap where a roof is cut by one contractor and detailed by another, which is where responsibility blurs and leaks begin. By treating the roofing side as a single accountable piece of the wider install, we ensure the transition from roof to equipment is clean, sealed, and clearly ours to stand behind.

Because penetrations are where warranty disputes most often surface, we document this work carefully and install it to keep your coverage valid. Every opening is detailed to the membrane manufacturer’s requirements, and we record how it was framed, flashed, and sealed so you hold clear evidence of correct installation. Should a leak ever be investigated near a penetration years down the line, that record shows the work was done properly rather than leaving you to argue the point. You get openings that are not only watertight but defensible, installed to a standard we are willing to warranty and backed by documentation that protects you long after the job is finished.

Planning Rooftop Openings and Curbs

Adding openings to a working roof is a decision worth understanding before the first cut, since the details shape both the immediate result and the roof’s long-term reliability. This section covers the practical questions building owners raise when new equipment or services need to pass through the roof, from what drives the work to how it protects the warranty and what happens with existing penetrations. The aim is to help you plan rooftop additions sensibly, so the openings you create serve their purpose without quietly undermining the roof they sit in or storing up problems for later.

When You Need Curb and Penetration Work

You need this work whenever something new has to pass through or sit on the roof: a new HVAC unit, added vents or conduit, solar or communications equipment, or any rooftop plant that needs support and a sealed opening. It also applies when an existing penetration has begun to leak or was poorly detailed from the outset. Any change that interrupts the membrane calls for proper penetration and curb work, because an improvised opening is one of the surest ways to introduce a leak into an otherwise sound roof.

How This Protects Your Roof Warranty

Roof warranties hinge on the membrane being installed and modified correctly, and penetrations are a common point where coverage is quietly voided. Cutting into the roof without matching the manufacturer’s detailing can invalidate the warranty on the whole system, not just the opening. By installing to the correct specification for your membrane, we keep that coverage intact and document the work as proof. Doing this properly safeguards the warranty, protecting the whole roof, a far larger asset than any single opening.

The Cost of Getting an Opening Wrong

The price of a properly detailed penetration is small next to the damage a failed one causes. A leak at a curb or pipe rarely stays at the opening. It tracks into insulation, decking, and the space below, often surfacing far from the source and making easy repair difficult. Add the disruption to whatever equipment the opening serves, and a rushed install becomes an expensive mistake. Spending a little more to detail the opening correctly the first time is almost always cheaper than the repeated repairs a poor one demands.

Retrofitting Openings Into an Existing Roof

Adding a penetration to an established roof differs from installing one during a new roof, and it requires care to avoid disturbing the surrounding waterproofing. We cut and detail the new opening so it integrates with the existing membrane, matching materials and terminations to what is already there. Where the roof is older, we assess whether the surrounding area is sound enough to take a new opening first. This means a retrofit ties in cleanly rather than becoming a weak patch in an ageing roof.

Dealing With Existing Failed Penetrations

Not every job is a new opening. Often an existing penetration or curb has started to leak because it was detailed poorly or has degraded over time, and it needs rebuilding rather than another bead of sealant. We investigate why the existing detail failed, then strip it back and reinstall it correctly, addressing the actual cause. A penetration resealed repeatedly usually signals that the details were wrong from the start, and rebuilding it properly ends that cycle for good.

Commercial Roof Penetration & Curb Installation

Why Penetrations Are the Weak Point

Our Process

Planning the Opening and Its Location

Framing and Structural Support

Membrane Termination and Flashing

Sealing, Testing, and Cleanup

Have a new roofing project?

Why Choose Markit Roofing for This Work

Planning Rooftop Openings and Curbs

When You Need Curb and Penetration Work

How This Protects Your Roof Warranty

The Cost of Getting an Opening Wrong

Retrofitting Openings Into an Existing Roof

Dealing With Existing Failed Penetrations

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Waterproofing & Coating Services

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