Corobrik AutoSpec

DESIGN OF BRICKWORK MOVEMENT

a) Moisture Expansion and Irreversible Moisture Expansion.

Reverse Moisture Expansion of brick ranges from 0.1 to 0.2mm/m length of walling depending upon the clay and firing process used.

In addition, irreversible moisture expansion occurs in all ceramic products as a result of the bonding of water molecules in the air to the fired clay material after the firing process. This process takes from two to five years, with at least half the movement taking place in the first six months after manufacture. Irreversible moisture expansion must be considered when designing and constructing a clay brick structure.

The extent of this expansion will vary with brick type falling into one of three categories. In order to accommodate this expansion, it is necessary for vertical movement joints to be provided at the maximum spacing given below.

CATEGORY % MOISTURE EXPANSION MAXIMUM SPACING OF 10 - 12MM JOINTS
Walling Parapets
i 0.00 - 0.05 16m 11m
ii 0.05 - 0.10 10m 8m
iii 0.10 - 0.20 5m 4m

N.B. Horizontal joints to be provided at every storey height if an infill to a concrete framed structure.

b) Thermal Movement of Clay Products - Reversible 30C change.

0.12 to 0.24mm/m length of wall.

CLAY FACE BRICK CLASSIFICATION

FBX - FACE BRICK EXTRA

Durable face bricks possess a high degree of size, shape and colour uniformity.

FBS - FACE BRICK STANDARD

Durable face bricks that are uniform in size and shape.

FBA - FACE BRICK AESTHETIC

Durable clay face bricks selected or produced for a highly individual aesthetic look derived from deliberate non-uniformity of shape and colour.

FORMAT

(Length) (Width) (Height)
Imperial 222 mm 106 mm 73 mm
Coro 90 222 mm 90 mm 73 mm
Coro Maxi 90 222 mm 90 mm 114 mm
Coro Maxi 140 290 mm 140 mm 114 mm
Jem 222 mm 140 mm 73 mm

All products are manufactured in accordance with SABS Standard specifications for Burnt Clay Masonry Units.

TOLERANCES AND DIMENSIONS

FBX FBS FBA
Tolerance in work sizes (L) (W) (H) (L) (W) (H)
Individual Unit 5mm 3mm 3mm 7mm 4mm 4mm 48-54/m2
Average Dimension 2.5mm 1.5mm 1.5mm 3.5mm 2mm 2mm Assume 12mm Joints
Warpage 90% of the units to have warpage of 3mm or less. NO unit to exceed 5mm warpage. No individual to exceed 5mm warpage. No requirements

FORMAT

(Length) (Width) (Height) Quantity/m2
Imperial NFP/NFX 222 mm 106 mm 73 mm 52
CoroMaxi 90 NFP/NFX 222 mm 90 mm 114 mm 33
CoroMaxi 140 NFP/NFX 290 mm 140 mm 114 mm 26

TOLERANCES

NFP NFX
Tolerance in work sizes
L W H
3,5mm 2mm 2mm
L W H
3,5mm 2mm 2mm
Average compressive strength Normal 7 MPa Normal 14 MPa

WHY CHOOSE TO BUILD WITH COROBRIK CLAY FACE BRICK?

The strength and durability of Corobrik clay face brick is matched by its intrinsic aesthetic qualities which are as rich as the beauty of nature itself. Corobrik offers a wide variety of colours, shades, shapes and textures to harmonize with and enhance any environment.

Value

When you build with genuine clay bricks you are adding value to your investment. In the years ahead you will really begin to appreciate the value of bricks because they last. Ageing actually adds to the natural beauty of clay face bricks, adding to the overall appeal of your building.

Everyday clay face brick is contributing to property investment - its strength, its durability and natural beauty.

Cost Saving

By building with genuine clay face brick by Corobrik, you will be saving the cost of plaster, paint and continuous maintenance because clay face bricks are virtually maintenance free. With their inherent qualities, they are designed to withstand the worst of the elements. In fact, their texture, colour and natural beauty improves over the years because bricks relishes the ravages of time.

Strength and Stability

Clay face bricks, which has been well fired and properly constructed, will produce strong, stable and durable buildings.

Thermal Insulation

Clay bricks built in the form of solid or cavity walls offer excellent protection against heat and cold.

Vermin Infestation

Brickwork correctly laid is devoid of cavities and crevices and therefore, impervious to vermin infestation.

Maintenance and Durability

A well constructed clay face brick wall should require no maintenance during its lifetime.

It will not be affected by weather conditions and will not deteriorate.

Colour

Variation of colours of clay products is natural and adds to the appeal to clay brick in that it blends well with the natural surroundings. Clay face brick are a beautiful, durable and economics contribution to the environment. For as long as we prefer to live in a world which combines both the built and natural environment in harmony, clay face bricks will continue to be a part of our lives.

WHAT YOU NEED TO KNOW ABOUT CLAY PLASTER BRICK WALLING

Clay brick cuts down on noise

Heavyweight clay brick walling is an ideal means of insulating buildings against noise. Even a single wall of clay brick is able to reduce noise dramatically. A double wall is capable of reducing noise by half as much again to produce a relaxed and peaceful environment, relatively free from outside distractions.

Clay brick keeps interior comfortable

Heavyweight clay brick walls also have an inbuilt ability to keep buildings cool in summer and warm in winter. During the day, clay brick absorbs and stores heat and this helps to keep buildings cool. During the cold nights, this stored heat is slowly released and this maintains the inside temperatures at a fairly comfortable level. This reduce energy costs.

Clay brick is fire resistant

Clay brick is fired at high temperatures during manufacture and therefore, is incombustible - it cannot burn anymore. So a brick wall does not help to spread the flames. In fact, it is highly resistant to collapse in the event of fire.

Strength and Stability

Walls built with quality clay face bricks, which are properly constructed, will produce strong, stable and durable buildings.

Thermal Insulation

Clay bricks built in the form of solid or cavity walls offer excellent protection against heat and cold.

Clay bricks are impervious

Clay brickwork, correctly laid, is devoid of cavities and crevices and therefore, impervious to vermin infestation.

Classification

Non face brick, known variously as plaster, common or stock bricks, are supplied in two categories.

NFP - Non Facing Plastered

Caly bricks that are suitable for general building work which is then to be plastered or rendered.

NFX - Non Facing Extra

Bricks suitable for use, plastered or unplastered, for general building work below damp-proof course or under damp conditions or below ground level, where durability, rather than aesthetics, is teh criteria for selection.

SPECIAL SHAPE BRICKS

To further enhance the potential for more inspired concepts in creative brickwork; Corobrik offers special shaped bricks as shown below. We recommend that you discuss your requirements with our staff in the early stage of design.

Note:

  1. Specials are manufactured in imperial format only.
  2. Most specials are manufactured with core holes.
  3. "Bar Marks" and other surface markings may not replicate the main product.

Bricks

EXPOSURE ZONE AND DURABILITY

Durability is the ability of a material to withstand the combined effects of the weathereing agents of moisture, soluble salts and thermal changes. Weathering action varies from moderate to severe, depending upon regional geographic conditions, the microclimatic conditions pertaining to the building's height and the material's position within the building. Parapets and copings, as an example, are clearly subjected to more severe exposure conditions than face brickwork protected by overhanging eaves. Internal face brick is not subject to the same degree of exposure as external face brickwork. Therefore, this section is primarily concerned with the selection of bricks for external face brickwork applications.

Recommended Specifying procedure

There are three factors to be considered when specifying face bricks for a particular application.

1. Geographic Consideration

In parts of Southern Africa, where the climate and peculiar local conditions combine to produce a harsh environment, certain types of face bricks used external, may suffer from accelerated weathering.

Broadly, our experience has shown that Southern Africa may be grouped in four exposure zones, which are defined in SABS 0164 Part 2 as follows:

Zone 1 Protected: All inland areas 30km from the coast.
Zone 2 Moderate:
  1. Sea spray zone in areas such as sea level on the east and north seaward sides of the Durban Bluff or other exposed coastal headland areas.
  2. The 15km coastal zone from Mtunzini north-eastwards to the Mozambique border (including Richards Bay and St Lucia).
  3. The coastal belt of Namibia.
Zone 4 Very Severe:
  1. Area such as Walvis Bay, where moisture from sea mist and high ground water tables, high soluble sulphates in the soil, and/or rapid temperature changes, combine to create the most severe exposure and weathering conditions known in our experience.
  2. Industrial areas where high acid and/or alkali discharges occur.

2. Macroconsideration

The immediate site environment e.g. site orientation, prevailing winds, driving rain index, the size and shape of the building and its relationship to surrounding structures and natural features, as illustrated in figures 1 and 2.

Figure 1: Protected Macroenvironment

Illustrates a protected macro environment, thus a single storey domestic dwelling is classified as protected. The high-rise structure and the house on the hill however should be classified one exposrue level higher by reason of their greater vulnerability.


Protected Macroenvironment

Figure 2: Moderate Macroenvironments

The moderate macro environment in the illustration would similarly require the highrise and the hilltop house to be treated as severe exposure situations.


Moderate Macroenvironments

3. Microconsideration

The degree of exposure to weathereing of brick elements within the building envelope, as illustrated in figure 3.

Figure 3: Microclimatic Environment

Demonstrates the different levels of exposrue of brickwork elements within the structure itself.


Microclimatic Environment

CLEANING OF CLAY BRICKWORK

GENERAL PRECAUTIONS

Staining can mar the appearance of brickwork, but incorrect cleaning techniques can cause permanent damage. Consequently, any proposed method of cleaning should be tested in a small unobtrusive area and left for at least a week to judge the results before the whole job is tackled. The techniques given here are intended for do-it-yourself work in removing relatively small areas of staining. A specialist contractor should be engaged for cleaning large areas of brickwork.

It is preferable to use wooden scrapers and stiff fibre brushes to avoid damaging the bricks; but where chemicals are to be used, the brickwork should be thoroughly wetted with clean Water to prevent it absorbing the chemicals and rinsed thoroughly with clean water afterwards. Adjacent features, such as metal windows and the area at the foot of the wall, should be protected from splashing from the chemicals.

Many of the chemicals recommended are caustic, acidic or poisonous, so care should be taken and protective clothing and goggles should be worn. Volatile solvents should only be used indoors under conditions of good ventilation. It is essential to identify the type of stain or deposit before any cleaning operations are undertaken.

PREVENTION IS BETTER THAN CURE

Cover face brickwork during building or renovating operations to prevent mortar and paint stains.

PREPARATION

Remember to thoroughly wet the brickwork with clean water before applying any chemical and wash down with clean water afterwards. The main are of unsightly staining arises from the operation of laying the bricks in mortar and the related quality of workmanship and management of the operation.

MORTAR AND MORTAR SMEAR

  1. Where possible, remove large pieces of mortar with a wooden or nylon scraper (not metal) which could damage the brickwork.
  2. Wet the brickwork thoroughly with water, starting at the top and working down.
  3. Wash the wall down with a dilute solution of a proprietary mortar cleaner, as per the manufacturer's instructions. Scrub brickwork using a stiff fibre brush (not metal).
  4. Never allow the mortar cleaner to dry on the brickwork. After scrubbing for a few minutes the wall must be thoroughly washed with clean water to remove the acid.
  5. Cleaning should be done in relatively small areas at a time working from the top to bottom.
  6. Should the mortar stain still be visible once the brickwork has dried out, steps 2 to 5 should be repeated.

NOTE: light coloured face bricks (yellow, buff and cream colours) are often susceptible to vanadium staining (see vanadium).

EFFLORESCENCE - WHITE CRYSTALS OR WHITE FURRY DEPOSIT

This usually disappears rapidly from new brickwork by the action of wind and rain. Dry brushing or damp sponging down the wall at times of maximum efflorescence will also help. The salts brushed off should not be allowed to accumulate at the base of the wall, otherwise they may be carried back into the brickwork by subsequent rain.

Efflorescence is usually a harmless phenomenon, although unsightly. Chemical cleaning is not necessary.

LICHENS AND MOSSES

These can be killed with a solution of Copper Sulphate (1kg to 10 litres of water) or alternatively, a proprietary weed killer. Vegetable growth is generally indicative of damp brickwork and will usually reappear if this basic cause is not cured. (Green staining which does not respond to this treatment is probably due to Vanadium salts form within the bricks.) Boiling water or steam is effective in cleaning mosses.

LIME AND LIME BLOOM

Follow treatment recommended for 'mortar' and 'mortar smear'. Lime staining in older brickwork, originating from the reinforced concrete structure, can be particularly difficult to remove. It is important to stop the flow of moisture through the structure to overcome the problem.

MANGANESE - (DARK BROWN)

Brush the stain with a solution of 1 part acetic acid and 1 part hydrogen peroxide in 6 parts of water.

PAINT

Apply commercial paint remover over a solution of trisodium phosphate (1 part to 5 parts of water by mass). Allow the paint to soften, and remove with a scraper. Wash the wall with soapy water and finally rinse clean water.

RUNNING WATER

Water running regularly down the surface of brickwork produces pattern staining and this can frequently be removed by scrubbing after wetting with a high pressure mist spray of cold water. If this is not effective, the treatment recommended for mortar should be followed.

RUST OR IRON

Wash down with a solution of oxalic acid (1 part to 10 parts of water by mass). (Brown staining which does not respond to this treatment, particularly at the junction of the brick and mortar, is probably due to manganese.)

SMOKE AND SOOT

Scrub with a household detergent. The more stubborn patches can be removed from the brick pores using trichloroethylene, although good ventilation is needed indoors.

TAR

Except where bricks are liable to surface damage, remove excess with a scraper, then scrub with water and an emulsifying detergent. If necessary, finally sponge with paraffin. Do not wet brickwork with water first.

TIMBER - (BROWN OR GREY)

These stains are due to water spreading tannin or resin from the timber across the bricks and mortar, and can normally be removed by scrubbing with a 1:40 solution of oxalic acid in hot water.

VANADIUM - GENERALLY GREEN/YELLOW IN COLOUR

Wash down with a 20% solution of Potassium Hydroxide. Scrubbing is not necessary. Do not wash the wall with clean water afterwards. (Hydrochloric acid should never be used on vanadium stains since it 'fixes' them and turns them brown.)

VARIOUS OILS

Sponge with white spirit, carbon tetrachloride or trichloroethylene. Good ventilation is essential indoors.

As part of an ongoing commitment to customer satisfaction, Corobrik has supplied this information in good faith. Corobrik is not responsible and cannot in any way be held accountable for poor workmanship or errors that may occur through the use of this information.