Substructure and installation of discontinuity joint cover | Comprehensive implementation guide, technical tips, tools and methods (Agor)

In the year 1404 (2025-2026), incorrect installation of the seismic joint cover is one of the three main causes of facade cracks and water penetration in buildings above 8 stories (Tehran Engineering System Report 1404). Incorrect substructure and non-standard installation can lead to an 85% reduction in the cover’s useful life and a threefold increase in repair costs. This comprehensive and up-to-date article is the most complete guide to substructure, installation, tools, access methods, and maintenance of seismic joint covers using 2025 technologies and Agor products.

If you want to obtain complete information about methods of closing and covering seismic joints in buildings, we suggest you read the specialized article Closing or covering seismic joints in buildings. In this article, we have reviewed the key points and standard implementation methods.

Why is substructure and installation of seismic joint covers more critical than ever in 1404?

According to Sections 3 and 6 of the National Building Regulations (1404 edition) and Standard 2800 (fifth edition):

• Seismic joints are mandatory in buildings with a length >45 meters or >8 stories.
• The cover must withstand at least ±100 mm seismic movement.
• Water penetration must be less than 0.01 liters/meter/hour (ASTM E331-2024).

With the SF-Pro Click & Lock 2025 series, Agor is the first company in Iran to receive CE + ISO 19650 (BIM Ready) certification for installing seismic joint covers.

Related reading: What is a seismic joint? (1404 requirements)

Substructure for seismic joint covers

The substructure is the heart of seismic joint cover installation. Even the best profile in the world with a weak substructure will last a maximum of 5–7 years.

Step 1: Precise control of joint width and level

The first and most important task is to accurately measure the joint width with laser meter. A deviation of more than ±2 mm will cause the cover to become crooked or open up in the future.

Step 2: Complete leveling of the substructure

The surface must be completely flat and free of irregularities. Maximum permissible deviation: 1 mm per meter. For leveling, use self-leveling epoxy mortars or laser straightedge.

Step 3: Industrial cleaning

Any dust, oil, grease, or concrete residue must be cleaned with industrial vacuum cleaner + solvent. The presence of even a thin layer of dust can reduce adhesion by up to 70%.

Step 4: Two-component epoxy primer

Before installing the base rail, be sure to apply Agor’s SF-Primer Pro primer. This primer:

• Increases adhesion by up to 3 times.
• Prevents rail corrosion.
• Drying time: 60 minutes

Step 5: Installation of hot-dip galvanized base rail

The base rail must be hot-dip galvanized with 275 g/m² (not cold galvanized!).

Anchor bolt spacing: every 40 cm (maximum).

Step 6: Backer rod and initial sealing

Use closed-cell PE foam with a diameter 25% larger than the joint width. Then inject SF-Sealant Pro silicone or polyurethane (minimum depth 8 mm).

Methods of installing seismic joint covers: Technical and cost comparison

Methods of accessing seismic joints at height

Method	Maximum height	Safety	Relative cost	Agor recommendation
Industrial rope access (IRATA Level 3)	Unlimited<\/td>	★★★★★<\/td>	Low<\/td>	Short-term projects<\/td>
Suspended scaffolding	100 m<\/td>	★★★★<\/td>	Medium<\/td>	Medium-term projects<\/td>
BMU (Building Maintenance Unit)	Unlimited<\/td>	★★★★★<\/td>	High<\/td>	Luxury towers<\/td>
Hydraulic lift	60 m<\/td>	★★★★<\/td>	Medium<\/td>	Glass facades<\/td>
Drone + installation robot	300 m<\/td>	★★★★★<\/td>	High<\/td>	Future 2026<\/td>

Substructure for seismic joint covers

Proper and precise substructure is one of the most important prerequisites in the installation process of expansion and seismic joint cover profiles. Substructure, as a critical stage, ensures that the final installation of the profiles is accompanied by the highest efficiency and durability.

“A strong and prepared substructure is a bridge between engineering ideas and practical execution. Without a standard substructure, even the most advanced joint cover profiles cannot provide their optimal performance.”
— Dr. Ali Rostami, prominent researcher in civil engineering (according to Today’s Construction publication)

Importance of substructure in installing expansion and seismic joint cover profiles

1. A solid foundation for installation:

Proper substructure provides an integrated and strong foundation for installing expansion and seismic joint cover profiles. Without proper substructure, even the best profiles cannot provide their optimal performance.

2. Increased adhesion and stability:

A prepared and clean surface improves the adhesion of special adhesives used for profile installation. This helps reduce the possibility of loosening or displacement of expansion and seismic joint cover profiles over time.

3. Reduced risk of execution defects:

Thorough inspection of substructure conditions prevents problems such as unwanted cracks, surface mismatch, or moisture penetration that could affect the performance of expansion and seismic joint cover profiles.

Conditions and requirements for substructure for optimal installation of expansion and seismic joint cover profiles

To achieve a standard and suitable substructure for installing expansion and seismic joint cover profiles, pay special attention to the following:

Surface uniformity:

• The surface must be completely flat and free of cracks and irregularities.
• If there are cracks or irregularities, they must be repaired and leveled using specialized mortars.

Cleanliness and absence of contamination:

• All dust particles, grease, and surface contaminants must be completely removed before installation.
• The use of appropriate tools for surface cleaning is a requirement.

Control of humidity and temperature:

• Environmental conditions such as temperature and humidity must be within standard ranges to prevent negative effects on adhesives and materials used.
• If necessary, the use of thermal or moisture insulation is recommended.

Structural strength:

The substructure must be structurally resistant and comply with national standards to bear the weight and forces applied to expansion and seismic joint cover profiles well.

Readiness for installation:

Before starting installation, all stages of substructure preparation including cleaning, leveling, and structural inspection must be carefully performed to ensure that no defects arise during the continuation of installation.

Table of substructure conditions for optimal installation of expansion and seismic joint cover profiles

Key factor	Required conditions	Recommendations
Surface uniformity	Flat surface, free of cracks and irregularities	Use repair mortars to level the surface.
Cleanliness	No dust, oil, or surface contaminants	Complete cleaning with appropriate tools before installation.
Humidity and temperature	Controlled conditions; appropriate humidity and temperature according to adhesive production standards	Use thermometer and hygrometer to control the installation environment.
Structural strength	Substructure resistant and compliant with national standards	Review the structure and perform strength tests if necessary.
Installation readiness	Complete preparation of substructure including leveling and cleaning	Hold coordination meetings between engineering and execution teams to ensure substructure quality.

Execution checklist for installing seismic joint covers

Item	Status	Description
Was the joint width measured?<\/td>	☐<\/td>	With laser meter<\/td>
Is the surface clean and dry?<\/td>	☐<\/td>	Free of dust and oil<\/td>
Was the primer applied?<\/td>	☐<\/td>	Dry for at least 60 minutes<\/td>
Is the base rail installed with HUS-H anchor bolts?<\/td>	☐<\/td>	Every 40 cm<\/td>
Was the backer rod installed?<\/td>	☐<\/td>	Diameter 25% larger<\/td>
Was the initial sealing performed?<\/td>	☐<\/td>	Depth 8 mm<\/td>
Was the cover installed with Click & Lock?<\/td>	☐<\/td>	No screws on the facade<\/td>

Maintenance and periodic inspection (Agor’s 10-year contract)

Summary and conclusion

In the year 1404, it is no longer possible to work with methods from 10 years ago. Incorrect substructure and installation of seismic joint covers means wasting billions of Tomans in the future.

With Agor’s Click & Lock system:

• 90% faster installation
• Without a single screw on the facade
• 20-year real warranty
• 100% beauty harmonized with your facade

If you also need a seismic joint cover with the highest quality standards in your construction project, we suggest you check out Agor products. You can also download Agor product catalog and review the technical specifications of the products.

If you need professional consultation, contact our experts. The future of Iran’s facades with Agor is without cracks and without leaks.

FAQ

1. Can a seismic joint cover be installed after the facade has been executed?

Yes! Agor’s SF-Retrofit 2025 series is installed without the slightest damage to the facade.

2. What material is used for the substructure of the seismic joint cover?

Depending on the project conditions, the substructure can include metal profiles, reinforced concrete, galvanized sheets, or a combination of these materials. The material choice depends on the cover weight, building type, and environmental conditions.

3. What is the best method for towers above 50 stories?

The combination of BMU + Click & Lock or robotic installation (Agor’s successful experience in 12 projects from 1403-1404).