Why Surface Mount is Essential for Waterproof Retrofit Projects | IP67 Enclosure Guide

This article covers the following content.

If you are an EPC general contractor or a renovation project contractor, and you are working on an outdoor/wet environment renovation project, this article will help you understand:

1️⃣ Why is there a significant waterproofing risk when concealed installations are used in renovation projects?

2️⃣ The waterproofing logic of surface mounting – Why can surface mounting achieve IP65-IP68?

3️⃣ Surface mounting solutions for three renovation scenarios

4️⃣ What materials should be chosen for waterproofing renovation projects?

This article was written by the BSUMWELL technical team. We are a manufacturer specializing in waterproof electrical enclosures, with products covering three major material series: PC/ABS plastic, stainless steel, and aluminum enclosures, with protection levels ranging from IP55 to IP68. We also support OEM/ODM customization.

A true renovation story—concealed installation saved on aesthetics but compromised waterproofing.

Case Study: Upgrading of External Monitoring Boxes at a Coastal Factory

A coastal factory was upgrading its external wall surveillance system. The client requested a "neat appearance, without protruding from the wall." To meet the client's aesthetic requirements, the contractor opted for a concealed installation solution—cutting grooves in the exterior wall and embedding the junction box flush with the wall surface.

After construction, the exterior did look neat and tidy. However, less than two rainy seasons later, problems arose:

• Rainwater seeped into the enclosure through the cracks in the wall, causing the internal wiring terminals to corrode.

• The monitoring system kept tripping, and maintenance personnel were unable to find the cause despite repeated troubleshooting.

• Upon disassembling the box, it was discovered that water had accumulated in the grooved area of ​​the wall on the back of the box, and water was seeping in through the gap between the box and the wall.

Repair costs: Demolishing walls, redoing waterproofing layers, replacing cabinets, and rewiring—these costs are dozens of times greater than the "aesthetic costs" saved by concealed installation.

The inherent flaws of concealed installations in renovation projects

The aesthetic advantages of concealed installation are obvious. However, in renovation projects, concealed installation has an inherent drawback:

The renovation project involves construction on existing walls, not a new construction project.

New projects can embed concealed boxes before the walls are sealed, allowing the waterproofing layer to be installed completely. However, renovation projects involve creating grooves in already completed walls—which directly damages the original waterproofing and insulation layers.

While concealed enclosures can achieve an IP67 rating in the laboratory, it is almost impossible to guarantee the same waterproof rating during on-site concealed installation in a renovation project.

Hidden waterproofing risks in concealed installations – Why lab data doesn't equal on-site performance?

The waterproof test for the concealed box was conducted in a laboratory, but the site was not a laboratory.

The IP rating test for the dark enclosure was conducted under ideal laboratory conditions:

• Precise wall opening dimensions

• The space between the enclosure and the wall is filled with standard sealant.

• The test environment was stable, with no thermal expansion or contraction.

However, the actual conditions at the renovation project site were:

• Uneven edges of openings in walls (especially in old brick or concrete walls).

• The gap between the enclosure and the wall needs to be filled with sealant or cement on-site, which can easily leave pinholes.

• Outdoor environments experience diurnal and seasonal temperature variations, causing sealing materials to repeatedly expand and contract with temperature changes.

Three major seepage paths in concealed installations

1. Gaps between the enclosure and the wall－After the grooves are cut, the gaps between the enclosure and the wall need to be filled on-site. Whether using cement, silicone sealant, or expanding foam, it's difficult to achieve a 100% seal. This is especially true for older walls with uneven surfaces and varying gap sizes, making it difficult for the filling material to adhere completely.

2. Moisture capillary penetration inside the wall－The wall itself contains moisture. After the recessed box is embedded in the wall, the moisture inside the wall will seep into the surrounding area of ​​the box through capillary action. Over time, condensation or even water accumulation may occur on the back of the box.

3. Grooving damages the exterior wall waterproofing layer－Exterior walls typically have a waterproof and insulation layer during construction. Concealed installation by creating grooves directly cuts through the waterproof layer, and even if repairs are made at the grooves, it's difficult to restore the original waterproofing performance. Rainwater seeps in along the wall cracks and eventually enters the enclosure.

The "amplified effect" of concealed waterproofing hazards in renovation projects.

in conclusion:Renovation projects using concealed installations pose a much greater risk of waterproofing problems than new construction projects.

The Waterproofing Logic of Exposed Mounting – Why Can Exposed Mounting Achieve IP65-IP68?

Sealing structure of exposed housing – complete closed loop

The exposed housing is a complete sealed body. Its sealing structure is as follows:

• The enclosure itself is either integrally molded or welded and sealed (seamless).

• There is a gasket between the cover and the housing.

• The cable inlet is sealed with Cable Gland.

• All fasteners must not penetrate the interior of the enclosure.

Simply put: the seal of the exposed casing is a "closed loop" - water cannot enter from any direction.

The mounting holes on the back do not penetrate the interior—a natural advantage of surface mounting.

The surface-mounted housing has mounting holes on the back for securing it to a wall. These mounting holes have a key design feature:

The mounting holes do not penetrate the interior of the enclosure.

This means that even if water seeps in through the fixing hole, it can only stay between the wall and the back of the box and cannot enter the sealed cavity inside the box.

This is a major advantage of surface-mounted waterproofing – the installation method itself does not compromise the waterproofing performance.

The sealing ring of the exposed casing – distributes stress evenly and ensures long-term reliability.

The sealing ring of the exposed housing is under uniform pressure:

• Tighten the cover plate screws in a star-shaped sequence to ensure even force distribution on the sealing ring.

• The compression ratio of the sealing ring is controlled between 25% and 35%, which ensures a seal without causing excessive deformation.

• The sealing ring material can be selected from silicone (coastal) or FKM (chemical plant) to adapt to different environments.

The sealing rings of the exposed enclosure can be replaced individually—the entire enclosure does not need to be replaced during operation and maintenance.

Exposed mounting solutions for waterproofing renovation projects – three scenarios

Quick reference table of surface-mounted solutions for three renovation scenarios

How do I use this table?

1️⃣ Confirm your renovation scenario

2️⃣ Find the corresponding installation method and recommended materials in the table.

3️⃣ Inspection Notes Section

4️⃣ For product selection support, please contact the technical team.

in conclusion:All three renovation scenarios are suitable for surface mounting; the key is to choose the right materials and mounting methods.

Material Selection – What materials should be chosen for waterproofing renovation projects?

Comparison of waterproof performance of three materials

Quick Reference Table for Material Selection Based on Environment

Our product line covers three materials, with protection ratings from IP55 to IP68, all supporting surface mounting. Flexible selection is available to suit different project environments.

View the full range of exposed waterproof casings

Frequently Asked Questions (FAQ) about Procurement

Q: Is it really impossible to use concealed installations in renovation projects?

A：If the environment is dry indoors, does not involve waterproofing standards, and the walls are newly built or not enclosed, concealed installation can be considered. However, in outdoor, damp, or renovation projects, concealed installation poses significant waterproofing risks—grooving damages the waterproofing layer, the gap between the enclosure and the wall is difficult to seal, and the sealant is prone to cracking due to thermal expansion and contraction. We recommend prioritizing surface-mounted options.

Q: Will water get into the mounting holes of the exposed casing?

A：The mounting holes on the exposed casing do not penetrate the interior of the enclosure. Even if water seeps in through these holes, it will only remain between the wall and the back of the enclosure and cannot enter the sealed cavity inside. Waterproof gaskets or sealant can be added to the mounting holes during installation to further improve waterproofing.

Q: Can a surface-mounted casing achieve IP68?

A：Yes. High-quality surface-mounted waterproof housings (such as those made of PC/ABS or stainless steel) can achieve IP67 or even IP68 ratings through an integrated sealing design, silicone sealing rings, and cable gland seals. The specific rating depends on the product design and sealing process.

Q: What materials should be chosen for waterproofing renovation projects?

A：For general outdoor use, choose UV-resistant PC/ABS; for coastal/chemical applications, choose 316 stainless steel; and for applications requiring heat dissipation, choose an aluminum casing. Specific selection requires a comprehensive evaluation based on the project environment, corrosion level, and budget.

Contact us for selection advice

Summary of the key points of this article

1️⃣ The renovation project used concealed installation, which poses a significant waterproofing risk—grooving damages the waterproofing layer, making it difficult to seal the gaps between the enclosure and the wall.

2️⃣ Waterproofing logic of surface mounting: complete seal + back mounting holes do not penetrate the interior + even stress distribution on the sealing ring

3️⃣ Surface mounting solutions for three renovation scenarios: outdoor walls, damp indoor spaces, and coastal/chemical areas.

4️⃣ Material selection for waterproofing renovation projects: Generally, PC/ABS is used for outdoor applications, 316 stainless steel is used for coastal/chemical applications, and aluminum is used for heat dissipation.

5️⃣ We can provide a full range of surface-mounted waterproof housings—IP55-IP68, with three materials available.

(Previous article:) Do you understand the basic differences between surface-mounted and concealed wiring? Please read the first article in this series, "Surface-mounted vs. Concealed Wiring: A Selection Guide for Waterproof Electrical Enclosure Retrofit Projects."》．

Next article preview: Waterproofing confirmed? Next, let's look at how to install exposed walls on different wall types—each with its own solutions for brick walls, concrete, and plasterboard. Please read the third article in this series, "Exposed Wall Installation Solutions for Different Wall Types: How to Install on Brick Walls, Concrete, and Plasterboard."

Contact us for exposed waterproofing renovation solutions.