Terrace Door Replacement for High-Rise Residential Buildings

Terace doors are one of the most used — and the most stressed — components of any high-rise residential building. As opposed to a patio door on the first floor of a residential building, the terrace door on the 20th, 30th, or 50th floor has to withstand the pressure of wind, changes in temperature, and daily operations, while keeping water and air outside of the unit. Once they start failing, these doors rarely stay a cosmetic problem — they develop water infiltration, become costly from an energy-saving perspective, and eventually turn into a liability for the building owner or co-op/condo board.

This article covers everything property managers, boards, architects, and facilities departments should know about terrace door replacement in high-rise residential buildings: why doors fail in high-rise buildings, what systems and materials are actually suitable for this kind of buildings, the engineering considerations, how to replace terrace doors in such buildings, and how to budget the project accordingly.

Why Terrace Doors Fail Faster in High-Rise Buildings

At height, the terrace door is not only the door, it becomes part of the structural envelope of the building. There are several forces that act on it that a ground-level patio door does not have to face:

• Wind load and pressure differential. In buildings that exceed ten stories, the pressure differential between the interior and the exterior of the building is substantial and the door system has to be engineered to withstand this pressure rather than just installed as a residential door system.
• Thermal cycling. Upper floors face bigger temperature differences and more sun exposure, leading to the degradation of seals, weather stripping, and gaskets.
• Water infiltration under the pressure of wind-driven rain. While in still weather conditions it works fine, the terrace door may leak badly once wind drives rain against the facade of the building at height — a common failure mode for older aluminum terrace doors that were not originally designed to withstand high-rise conditions.
• Mechanical stress due to daily usage. Rollers, tracks, and multi-point locking mechanism in a sliding terrace door become worn faster in high-rise applications, because people use terraces frequently, thus the doors get more mechanical stress.
• Age of the original building stock. Many high-rises constructed during the 1970s-1990s had terrace door systems that were not designed according to modern standards of thermal-break and air/water infiltration standards, making even well-maintained original doors obsolete.

Signs That Your Building’s Terrace Door Replacement Need to Be Replaced, Not Repaired

There are several symptoms that can tell the building owner or co-op/condo board that the door system needs to be completely replaced, not repaired anymore:

1. Water stains or damage on the walls near the door, especially after the wind-driven rain.
2. Difficulty sliding or locking the door or frequent repairs of the hardware in the unit.
3. Condensation between glass panes of the double or triple glazed unit, which means that the glass unit’s seal has failed and the unit has to be completely replaced.
4. Drafts from the terrace even if the door is closed and locked.
5. Corrosion of aluminum frames and steel parts, especially on the sill.
6. Systemic nature of repeated resident complaints regarding a number of units with the same terrace door on the same elevation of the building, which usually means a systemic problem, not isolated wear and tear.
7. Doors that precede the major upgrade of energy code in the jurisdiction, because in most cases, they can’t be brought up to the current performance level through repair.

Types of Terrace Door Systems Suitable for High-Rise Residential Buildings

Not all terrace door systems are suitable for high-rise applications. Below you can find the types of systems used in tall residential buildings.

Thermally Broken Sliding Terrace Doors

This is the most common type of terrace doors used in high-rise residential buildings. Thermally broken sliding terrace door uses polyamide strut to separate the interior and exterior parts of aluminum frame, which decreases heat transfer while preserving structural integrity. These systems are engineered specifically for high-rise residential applications with multi-point locking hardware and capability to integrate into curtain wall system or a fixed window system of the building.

Lift-and-Slide Doors

In case of larger terrace openings or premium apartments, it becomes popular to use the lift-and-slide doors. In this configuration, turning the handle raises the panel so it disengages from the seal and slides along the track, then lowers it to reconnect with the seal once it is fully closed — three-stage operation which provides better air and water-tightness than a standard slider while allowing much larger glass openings. It is important for a high-rise building, because the pressure differential makes tight seals a must to prevent leakage.

Swing and Hinged Terrace Doors

Swing or hinged terrace doors — French doors, in some cases — remain common in smaller terrace openings or where local design guidelines ask for a traditional look. They provide relatively simple hardware and weatherproofing at one hinge line, but require space for the swing radius.

Bi-Fold and Multi-Slide Doors

In case when the opening of the terrace should be as wide as possible to maximize the opening, bi-fold (accordion style) doors and multi-slide doors are used in this case. Such solutions are more common in renovations of premium or penthouse levels than unit-by-unit replacement program, because of the complexity and the cost of installation.

Engineering Considerations Specific to High-Rise Applications

Wind Load and Structural Testings

All the terrace doors that are supposed to be used in a high-rise residential building should have the documentation on wind load and structural performance. Some of the high-performance sliding door systems have been tested to withstand wind speed that exceeds 200 km/h and air pressure that reaches 2000 Pa. These numbers reflect the conditions on top floors of residential towers, which is a substantially higher performance level that patio doors in single-family houses are expected to have.

AAMA and Industry Performance Classification

Commercial-grade terrace doors and balcony doors systems are usually classified according to AAMA (American Architectural Manufacturers Association) performance classification, which includes air infiltration resistance, water penetration resistance, and structural load resistance. When evaluating the replacement products, contact the manufacturer to receive AAMA class rating of the door system and its specific size — this number depends on size and configuration of the panel, not only the product name.

Thermal Performance and Energy Code Requirements

Thermally broken frame with the polyamide strut became standard for high-rise residential terrace doors, because of their energy performance and decreased condensation risks, which is a common issue for old non-thermally broken aluminum terrace doors. There are also more stringent energy code requirements for replacement glazing and doors in multifamily buildings in many jurisdictions, so it is a good idea to consult the current requirements with your local building department before finalizing the specification, because product that complies with the codes a decade ago, might not be compliant now.

Impact Resistance and Storm Resistance (Coastal or High-Wind Zones)

For buildings that are located in coastal or hurricane zones, terrace doors with laminated glass are worth considering, even if they are not mandatory by the code, because laminated glass is more resilient to wind-borne debris damage than standard tempered glass, thus the terrace door and hardware that go with it withstand such storms better.

Building Codes, Board Approvals, and Other Regulatory Considerations

Terrace door replacement in a high-rise residential building is not only a purchasing decision, but usually involves several layers of approval:

• Permits from building department. In most cases, replacement of exterior doors and glazing requires a permit, especially when it is related to structural elements of the building or fire separations.
• Approval of the co-op/condo board and building management. Since terrace doors are part of the building’s facade in most cases, replacement of the doors by individual unit owners is impossible and most buildings have centralized building-wide replacement programs, rather than piece-meal replacements of the individual units.
• Facade and envelope compliance program. Periodic facade inspection laws of many cities require buildings to report and, if necessary, fix deteriorated parts of facade, which includes terrace doors and sealant joints around them.
• Historic district or landmark protection. Buildings in the historic districts are subject to additional regulations on frame color and sightline dimensions, and sometimes even material type, even when replacing terrace doors with the state-of-the-art systems; frame color matching is often required.
• Fire and egress codes compliance. If terrace door also serves as an egress path, replacement product has to comply with applicable fire and egress codes for the width and operability of the opening.

The Terrace Door Replacement Process, Step by Step

1. Building-wide assessment. A qualified glazing contractor or facade consultant inspects representative units and documents condition, sizes, and performance issues of existing terrace doors rather than assuming that all doors in the building are the same (usually, in old buildings there are several generations of doors installed throughout decades of piece-meal repairs).
2. Specification and product selection. Based on wind load requirements, energy code minimums, and aesthetics of the building, the design team selects terrace door system and finish, usually piloting one or two sample units before ordering building-wide replacement.
3. Board and regulatory approvals. Specification goes to the co-op/condo board for approval and permit applications are submitted to local building department.
4. Manufacturing and lead-time planning. Usually, the terrace doors for high-rise buildings are custom-manufactured, so lead times could range from several weeks to few months, depending on the manufacturer and current order volume — has to be taken into account in any building-wide replacement schedule.
5. Installation in phases. Instead of replacing all the terrace doors in the building at once, projects are usually implemented in phases — by floor or by stack line to manage the resident disruption, access logistics, and weather-dependent installation windows.
6. Removal and installation. Existing doors and frames are removed, the opening is checked and prepared, flashing and sealant details are reinstated, and the new door is installed and tested.
7. Quality control and water testing. Good contractors perform water and air infiltration testing on a sample of completed installations to prove that new doors perform to the specifications.
8. Communication with the residents and punch-list. Installation is happening in the occupied units, so resident communication and final punch-list inspection are critical for smooth closure of the project.

What Makes the Cost of Terrace Door Replacement So High?

Costs depend on market, door system and building complexity, but the main cost drivers are universal:

• Type of terrace door system and its size. Thermally broken sliders are cheaper than lift-and-slide or multi-slide systems of the same size.
• Glass specification. Impact-resistant laminated glass, high-performance low-e coating and increased size of glass increase the cost compared to standard insulated glass units.
• Access and logistics. High-rise installations usually require swing-stage or scaffold access, which is more expensive than ground-floor installation and is highly dependent on building height and facade design.
• Non-standard sizes and openings. Many old buildings have terrace openings of non-standard sizes and need custom-made rather than off-the-shelf units.
• Volume and phases. Building-wide replacement projects usually achieve better pricing per unit than piece-meal replacements of individual units, because manufacturers and contractors are able to plan production and crew schedules in advance and buy materials in bulk quantities.
• Code-driven upgrades. If the replacement triggers other code-required upgrades (structural reinforcement at the opening, fire-rated assembly, egress width modification), this cost should be budgeted in addition to the cost of the door system itself.

Given this variability, most facade consultants recommend getting at least three qualified quotes based on the identical detailed specification, rather than comparing prices on general “terrace door replacement” line items that do not always reflect the same scope of work.

Choosing a Contractor for High-Rise Terrace Door Replacement Work

• Ask for the high-rise project references, not for general experience in residential door installations. Installation and sealing of the terrace door at the 30th floor are different processes than the installation on the first floor in many respects.
• Verify contractor’s experience working with your building facade. Integration with existing curtain wall, window wall, or punched openings vary greatly depending on the building, so having a contractor with experience working with similar facade systems is crucial.
• Check the manufacturer certification and warranty terms. It is important to check whether installer is factory-certified for installation of the specific door system that is going to be installed, because it usually affects the validity of the warranty.
• Ask about water testing procedures. Installer who volunteers to do water testing on the completed installations is demonstrating a higher level of quality control than the company that does not even mentions the testing as a possibility.
• Evaluate his experience in board and local permitting process. Contractor who understands the local process of facade and permitting is going to implement the project faster than the contractor who doesn’t have any experience in this process.

Tips to Maintain the New Terrace Doors Longer

• Annual hardware inspection. Rollers, tracks, and multi-point locks should be inspected and lubricated once a year.
• Clean tracks and weep holes. Debris accumulation in tracks and weep holes is one of the most common reasons for early water infiltration issues.
• Annual inspection of the exterior sealant joints. Sealant around the door frame deteriorates faster in high-rise buildings because of the UV radiation and thermal cycling, and failure of this seal is one of the most common reasons of water intrusion even with the high-quality door.
• Immediate replacement of the damaged glass seal. Appearance of fogging or condensation between glass panes means that glass seal has failed and it should be replaced immediately, because it means that the unit lost thermal efficiency.
• Building-wide maintenance log. Building that keeps track of terrace door problems on the whole building level, instead of unit by unit, discovers systemic problems (such as bad batch of hardware or design defect on certain elevation) much earlier.

Conclusion

Replacement of terrace doors in a high-rise residential building is a very different project than homeowners’ patio door replacement. Wind load, pressure differential, thermal performance, board approvals, and installation logistics play the role in the project which impacts structural envelope performance, resident comfort and maintenance costs. Buildings which tackle terrace door replacement as the building-wide program, with proper engineering specification, competitive bidding, and installation planning, get better results consistently than those which address failing doors unit by unit as the complaints come in.

Preventive maintenance of the terrace door, rather than waiting for water damage or resident complaints to force the issue, remains the most cost-efficient approach to protect building envelope and comfort of the building residents for decades to come.

Frequently Asked Questions For Terrace Door Replacement

How do I know if my building’s terrace doors need to be replaced instead of repaired?

Warning signs include water staining near the door frame, condensation trapped between glass panes, doors that are difficult to slide or lock even after repair attempts, visible drafts, and corrosion on the frame or hardware. If these issues appear across multiple units on the same elevation, it usually means that there is a systemic problem that should be addressed with the replacement program, not repair.

What type of terrace door is best for a high-rise residential building?

The most commonly chosen for high-rise residential projects are thermally broken sliding terrace doors as they combine good thermal insulation properties, high strength and multi-point locking security. The lift-and-slide systems could be an optimal choice for bigger apertures, in case of better sealing, whereas swing or hinged doors could be a preferable solution for smaller terraces or specific requirements of a project.

Should high-floor terrace doors have any wind load or pressure rating?

Yes. As the pressure differential between interior and exterior space becomes quite high when the building has more than ten stories, terrace doors should be tested and certified as a high-rise terrace door and not standard residential patio door that is made for installation on the ground level.

Is any co-op/condo board consent required for replacing terrace doors?

For the most part, yes. Since terrace doors are regarded as part of the building’s facade, no owner could replace them individually without board consent, as well as most buildings organize the program of central replacement of all terrace doors of a building as a whole rather than individual units.

How long do the processes of the terrace doors replacement of a whole building usually last?

The duration depends on the size of a building and particular door system but custom manufactured high-rise terrace doors require some lead-time (a couple of weeks up to several months) and installation is performed in phases of floors or stack lines what makes the process much longer than the replacement of one unit.

What is a thermally broken door?

It has an insulated gap filled with a non-conductive material (typically it is polyamide strut) separating interior and exterior parts of the aluminum frame which significantly reduces the heat conductivity and the risk of condensation of a thermally broken door comparing with the standard aluminum door when the metal passes through from the exterior to interior side.

Do we need impact-resistant terrace doors outside hurricane zones?

Impact-resistant laminated glass is used mainly in coastal areas or in hurricane zones, but in other places where there are lots of strong winds the buildings might choose such glazing for added strength and security since laminated glass is less vulnerable to breaking than tempered glass.

How expensive is terrace doors replacement in high-rise buildings?

The costs greatly depend on door system, glass specification, access and scaffolding requirements, custom door size requirements and the way of replacement (building-wide or unit by unit). That’s why it would be better to compare prices of different contractors based on an identical specification of the project rather than general price ranges.

Is it possible to replace terrace doors without bothering the residents?

Although disturbance is inevitable due to the fact that work will be performed in the interior space, phased work and prior resident notification will minimize the disturbance. Most contractors will perform all the work according to the plan approved beforehand by residents within the framework of building-wide replacement program.

How often should be inspected hardware and seals of terrace doors after replacement?

Annually, because the hardware (rollers, tracks, multi-point locks) and exterior joints of sealants of a door placed at height are affected more by sun rays, temperature cycles and wind-driven rain compared to similar hardware installed at ground level.