Case 3

Peeling of Paints Near to the Ground

Introduction

The peeling of the paint is evident on this section near the ground. The peeling of paint can be attributed to a number of factors. A few of such factors are using too many layers of paint, improper painting surface preparation, high temperatures, water damage, poor quality of paint, failure of water proofing membrane, etc.

The peeling of paints near to the ground can be attributed to the following reasons:

Lack of Adhesion
Water Damage
High Humidity Environment
High Exposure to Sunlight
Incompatible Paint Used

Peeling occurs when there is a lack of adhesion between the paint and the surface it is painted on. A number of factors could have contributed to the loss of adhesion. One such factor would be improper preparation of the surface. For the paint to stick properly, the surface should be prepared adequately. An uneven or unprimed surface will cause any coating applied to it to peel quickly. Hence, proper preparation work to the surface is required before painting begins.

Another factor would be water damage. As this section of the building is near to the ground, rising dampness will cause the substrate that the paint is applied on to be constantly wet or damp. Paint does not adhere well to wet or damp surfaces, resulting in the peeling of the paints.

High humidity in poorly ventilated commercial buildings can cause moisture build-ups in the walls, leading to the blistering of paint. It results in dampness, which stimulates the growth of mildew and mold over time.

Exposure to intense sunlight makes oil-based paints vulnerable to cracking. Elastic and latex paints tend to contract and expand when exposed to direct sunlight, which weakens their adhesive bonds. As the paint in the image is used in an outdoor area, it makes the paint more susceptible to sunlight.

Lastly, the paint used may not have been compatible with the surface. Some surfaces are not compatible with certain types of paints. Some synthetic polymer materials can prevent the paint from having full adhesion, Oil-based paints are affected by galvanized steel and concrete, Wood surfaces can produce natural oils which can prevent paint adhesion. Smooth surfaces are unable to form a mechanical adhesion with some paints, so any layers applied to them could peel off immediately. In this case, the surface might have been smooth which led to poor adhesion with the paint.

Preventive Measures

Design:

Specify the use of a breathable paint system to reduce trapped moisture and to avoid wetness and dampness of basement walls. Fungiresistant paint is also required. Avoid the use of Alkyd based paint on concrete surfaces that may lead to saponification (i.e. the formation of oily patches)

When selecting the paint, consider substrate, environment, application method, feasibility of surface preparation, over coating interval, and appearance.

Construction:

Ensure adequate curing of substrate before paint application to avoid shrinkage cracks. Clean surface and use clean tools. Avoid prolonged storing, inadequate stirring, use of incompatible thinner/solvent, or mixing with leftover paints from previous batches.

Ensure that coatings are always applied in a minimum of two coats. The material should possess some degree of flexibility (i.e. be elastomeric) to reduce the risk of cracking due to thermal/moisture movements.

If the paint is brush-applied, the second coat should be at right-angles to the first coat to help eliminate pinholes and avoid chemical attacks.

Corrective Measures

Regular inspection is important to detect or identify the defects immediately so that corrective maintenance could be carried out at the early stages to prevent further complexities. Visual inspection techniques or instrumentation techniques can be used for regular inspections.

Diagnostics of Defects:

Visual Inspection

Inspect at reasonable intervals to identify any peeling of paint.

Use of Moisture Meter

A Moisture meter can be used to measure the reduced resistance between two probes when they are embedded in damp materials. It can be used to trace areas of walls affected by rising damp or rain penetration. Measurements should be taken at regular intervals to distinguish between surface dampness or dampness within the wall.

Remedial

The remedial steps are as follows:

Ensure proper drainage of gutters and downspouts flowing away from home.
Inspect at reasonable intervals to identify necessary repairs (depending on type of coating, degree of exposure to elements, and accessibility, it can range between 3–10 years).
Complete all repairs of damages due to wear and tear by washing down and removing defective paint film. Apply sealer/primer (if necessary), and repaint.

Standards

Paints:

BS EN 1504-2 Products and systems for the protection and repair of concrete structures. Definitions, requirements, quality control and evaluation of conformity. Surface protection systems for concrete

BS 6150 Painting of buildings. Code of practice

SS 542 Code of practice for painting of buildings

SS 150 Specification for emulsion paint for decorative purposes

SS 554 Code of practice for indoor air quality for air-conditioned buildings

BS EN ISO 12944-4 Paints and varnishes. Corrosion protection of steel structures by protective paint systems. Types of surface and surface preparation

BS EN ISO 1513 Paints and varnishes. Examination and preparation of test samples

ASTM C33/C33M-16e1 Painting of buildings. Code of practice

ASTM E1667-95a Paints and varnishes. Corrosion protection of steel structures by protective paint systems. Types of surface and surface preparation

ASTM E903-12 Paints and varnishes. Examination and preparation of test samples

BS 4873 Code of practice for painting of buildings

Waterproofing:

BS 8102 Code of practice for protection of below ground structures against water from the ground

SS 637 (formerly CP 82) Code of practice for waterproofing of reinforced concrete buildings

AS 3740 Waterproofing of domestic wet areas

BS 5427 Code of practice for waterproofing of reinforced concrete buildings

Concrete:

BS EN 1992-1-1 Eurocode 2: Design of concrete structures. General rules and rules for buildings

BS EN 1992-3 Eurocode 2. Design of concrete structures. Liquid retaining and containing structures

BS 8204-2 Screeds, bases and in situ floorings. Concrete wearing surfaces. Code of practice

CP 65-1 Code of practice for structural use of concrete – Design and construction

Repair Works:

BS 8221-1 Code of practice for cleaning and surface repair of buildings. Cleaning of natural stone, brick, terracotta and concrete

BS 8221-2 Code of practice for cleaning and surface repair of buildings. Surface repair of natural stones, brick and terracotta

SS 509-1 Code of practice for cleaning and surface repair of buildings – Part 1 : Cleaning of natural stone, brick, terracotta, concrete and rendered finishes

SS 509-2 Code of practice for cleaning and surface repair of buildings – Surface repair of natural stones, brick, terracotta and rendered finishes

BS 8000-0 Workmanship on construction sites. Introduction and general principles

BS 8000-9 Workmanship on building sites. Cementitious levelling screeds and wearing screeds. Code of practice

ASTM C1496-18 Eurocode 2: Design of concrete structures. General rules and rules for buildings

BS 8298-1 Code of practice for the design and installation of natural stone cladding and lining. General

References

[1] PPD Painting. (2019). Why Does Paint Peel – Most Common Reasons. PPD Painting. Retrieved from https://www.ppdpainting.com/blog/why-is-my-commercial-paint-peeling/

[2] Hughes, K. (2015). 8 Simple Tips to Correct Exterior Peeling Paint. Performance Painting. Retrieved from https://www.performance-painting.com/blog/8-simple-tips-to-correct-exterior-peeling-paint

[3] SS652:2019 Singapore Standard Maintainability of Facilities