How to renovate a concrete wall or façade with hairline cracks.

The Problem

The exterior walls of facades are subject to extreme conditions and many stresses due to contraction as a result of changing temperatures. At the same time, they need to protect against degradation from continuous exposure to the elements.

Climates around the world are becoming more extreme with increased rainfall and above average temperatures. Bricks, joints, cement, concrete eventually crack and delaminate due to adverse weather conditions.

Due to the continuous movement of buildings and exposure to harsh weather conditions, hairline cracks will develop. Freeze thaw cycles will expose these weaknesses , exposing the steel reinforcement bars within the concrete to accelerated corrosion and eventually concrete spalling.

Once this process commences it is critical to act fast to protect the structure and integrity of the building. The economic losses are high in terms of asset write off and lost productivity.

This is the start of water infiltration problems in the wall which can cause significant damage if not resolved in time. Each winter, with the frost and thaw, the degradation will become more and more pronounced.

 

Water ingress into the building fabric will enhance the problems and will also result in rising damp, mould and Carbonation of the concrete.

Concrete carbonation is the result of an electrochemical reaction between carbon dioxide, moisture and calcium hydroxide that is present in cement, producing calcium carbonate.

Calcium carbonate lowers the alkalinity of the concrete from pH 12 to 9, making the steel rebar more vulnerable to corrosion.

Carbonation can advance at a rate of 1-5 mm per year dependant on the porosity and permeability of the concrete façade.

Elastoflex is a cost-effective solution to prevent carbonation. It allows the concrete to breathe and release moisture trapped within and prevents penetration by moisture and carbon dioxide into the concrete from the atmosphere.

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The Solution

Elastoflex

Elastoflex is a quick, simple and economical solution for the sustainable renovation of brick and concrete facades. It has a proven global track record with successful projects in Brussels, New York , Mexico and Denmark where large buildings are protected by  Elastoflex for many years in extremes of climatic conditions.

Elastoflex is a unique breathable coating with 600% elasticity, it will bridge hairline cracks (<1mm) and can be applied direct to concrete and brickwork, no additional primers are required.

It is CE class 2 certified and allows the substrate to breathe while preventing damaging carbon dioxide and moisture penetrating the concrete, the cause of carbonation and concrete decay.

It is an Ecological and Sustainable coating with Low Odour and Low Emissions. Available in an extensive range of RAL Classic and NCS colours in a satin finish for free delivery throughout the UK.

Due to its excellent flexibility Elastoflex will bridge hairline cracks (<1mm). Where larger cracks have developed they should be repaired with a cement based mortar . A roof fleece should then be applied over all areas repaired and coated through with Elastoflex to provide additional protection.

The fleece is designed to absorb building movement and will prevent water penetrating the structure.

Anticarbonation Coating Protects for 20 Years.

Elastoflex  exhibits supreme elasticity when applied to brickwork and concrete facades. It acts as an Anti-Carbonation coating  preventing spalling and building degradation as a result of corrosion of the steel reinforcement bars within the concrete.

 

Elastoflex can be applied by airless spray in two coats to achieve the recommended dry film thickness of 350 microns per coat. It has a theoretical coverage rate of 0.8 Kg per square metre when two coats are applied.

It complies with the requirements of standard EN 1504-2 and is CE marked. It has an expected service life of 20 years.

Elastoflex is a Single Coating System developed in Belgium and produced in the West Midlands. It is a unique primer finish, no additional primers or adhesion promoters are required. It is easy to apply, fast drying and safe to use. It is available in 5kg and 25kg containers in an extensive range of colours and free delivery.

Benefits & Performance

The service life of the system is in excess of 20 years. The system has a global track record Waterproofing, Protecting and Decorating brickwork, exterior walls and concrete facades. It delivers great benefits to the owner of the building in terms of a cost-effective solution to protect from concrete carbonation and corrosion. For the applicator it is a simple safe single product solution which is easy to apply with no hazards in relation to fire, product health and safety.

For the project manager:

  1. Protects Buildings against concrete decay.
  2. 20 Year performance. CE Marked.
  3. Excellent Elasticity and Durability.
  4. Ecological and Sustainable paint
  5. Low VOCs and Low Emissions
  6. Low Odour, minimal disruption.
  7. Made in West Midlands.
  8. Wide choice of RAL & NCS colours.
  9. Free Delivery no hidden costs.

For the applicator:

  1. Single product solution. No primers.
  2. Breathable coating applied direct to concrete.
  3. Bridges hairline cracks. Apply roof fleece to bridge larger cracks.
  4. Easy to apply, Fast drying
  5. Low Odour, Low Emissons. No fire risk.
  6. No overcoating or pot life restrictions.
  7. Made in the West Midlands.
  8. Wide choice of colours.
  9. Free Delivery to site.
Preparation

Weather

As with any outdoor project, try to avoid starting a job in wet conditions. A minimum of 10°c (50°f) and no rain forecast during and immediately after application are required to be able to apply the product successfully. Above 15°c (59°f), working conditions are perfect and enable higher productivity. If the project is located in a very hot area with very intense sunshine avoid applying the system when the sun is the most intense and  work early in the morning or in the late afternoon.

If you are working in humid climates, and especially if it is cold after sunset such as in the autumn , be sure to complete the job a few hours before dark to avoid condensation covering the fresh paint and slowing the drying. If you are working at dawn, be mindful of condensation on the surface.

Surface preparation

The surface must be clean, dry and free from contamination. New masonry must first be brushed with a wire brush to remove the remains of any mortar.

Elastoflex will bridge hairline cracks of <1mm. Repair mortars will be necessary for larger cracks in the concrete. These areas should be reinforced using roof fleece for added protection.

Existing coatings

Existing painted surfaces can be cleaned using a high-pressure cleaner with a power of 275 bar - 4000 psi, equipped with a rotating nozzle. This will remove any loosely adhering paint and damaged concrete. Feather the edge of the intact coating to provide a smooth transition with the exposed concrete.

Smooth surfaces

On smooth concrete the surface should be abraded with hand or power tools to roughen the surface. On these areas apply a mist coat of Elastoflex thinned 25% with tap water to penetrate the surface.

Equipment

Elastoflex is usually applied with a brush on localised areas, and with an airless spray gun on the main surfaces. For airless spray use a pressure of at least 180 bar or 2600 psi and a nozzle size between 0.015 and 0.023 inches.

If spraying is not possible, it can be applied by roller. It will take longer, and you will need to apply more coats to achieve the minimum thickness required.

For application by roller, it is recommended to use 14 mm (½ inch) polyamide rollers

At the end of the work, clean your equipment with tap water.

System Application

The application

Elastoflex is supplied ready to use, stir it mechanically for several minutes.

Apply the first coat of Elastoflex over the entire surface to be protected. A wet film thickness of 685 microns should be applied to achieve a dry film thickness of 350 microns per coat. Elastoflex with 600% elasticity will bridge hairline cracks <1mm.

Allow the paint to dry for a minimum of 24 hours before applying a further 350 microns of Elastoflex over the entire surface.

Elastoflex should be applied uniformly with a total theoretical coverage of 0.8kg per square metre. Application by roller will require 3-4 coats to achieve the recommended dry film thickness.

After 4 hours of drying at 20 ° C, the coating is dry and resistant to rain.

Application with Fleece

Where larger cracks have been repaired with cement mortars a  fleece should be applied to reinforce the structure in this area. It usually takes two people to apply the fleece simultaneously with the first coat of Elastoflex.

Start with the highest point. Hold the sail roll against the surface and gradually unwind it  50 cm ( 20 inches) down.

The second person applies at the same time a layer of Elastoflex on the start of the fleece so as to fix it to the wall.

Then, while holding the roller so that its weight does not take off what has just been placed, gradually descend a 2-3 metres and cut the fleece. The second person simultaneously applies the first layer of Elastoflex over the entire surface of the fleece so as to fix it entirely on the surface.

Repeat the operation right next to it, overlapping the fleece on the one already installed by at least 5 cm (2 inches) and cover the entire surface, gradually descending to the ground.This operation consumes the most time but is absolutely necessary to guarantee the long-term performance of the system on facades with active cracks.

Allow the paint to dry for a minimum of 24 hours before overcoating. Apply a second full coat of Elastoflex over the entire surface. A total dry film thickness of 700 microns is required once the two coats have been applied. If this has not been achieved, do not hesitate to apply a third coat.

After 4 hours of drying at 20 ° C, the coating is dry and resistant to rain.

Elastoflex is available in a wide variety of colours from the RAL Classic and NCS ranges. Since it has excellent opacity, we recommend using a different colour per coat. This will help you to distinguish between layers and visually check two full coats have been applied.