Author/Source: Brien Walker
You might be forgiven for thinking that a wet, insignificant lump of clay, burnt to form a relatively featureless rectangular shaped loaf is hardly the stuff of legend, especially when so many billions exist – but you could be wrong!
Common, plentiful, small, dense, compact and individually unprepossessing are apt descriptive words. Why, when combined in numbers the components even become lost to sight within the mass of the structure(s) formed. They surround much of our built environment, have invaded, nay, dominate the constructed domain, but few give rightful credit to this most amazing of inventions. We call them brick and the traditional ‘hand-made’ is the most remarkable unit of them all. These technically perfect innovations combine structural component with durability, ease of use and an aesthetically pleasing warm appearance. Their long history has also had profound social, economic and even artistic impact on our society and they are evocative daily reminders of our past. We can perhaps hate many of the structures formed from the modern mass-produced artifact but invariably find something to admire in the solid rich textured surface and wide regional color variation belonging to the handmade brick. We can see this even when they form seemingly endless rows of monotonous ‘back to back’ industrial terraced dwellings, the crumbling ivy-clad canal arch, redundant railway structures or a towering industrial factory stack. What other almost seemingly insignificant made-made artifacts can you name, that have had such a profound effect on this, our built environ? Why it has even been designed in size, weight, shape, and style to perfectly fit the craftsman’s hand, so that it can literally be utilized hundreds of times within the hours of the working day.
Socially acceptable, considered aesthetically and artistically pleasing, this simple building block, adapted in form and structure to a very human scale, has been with us since very early times. Some authorities hold that they have been manufactured for 12,000 years, which makes our ancient circa 2150BC Stonehenge a very humble ‘newcomer’ indeed. Incredible! The Encyclopedia Britannica lists the oldest known brickworks as being Samarian, sited between the Tigris and Euphrates. However, if you believe the Old Testament then you might know the Tower of Babel was constructed of brick. So for that matter of fact was Babylon, the Sakkova stepped Pyramid, the Great Wall of China and Bengal’s Paharpur Temple to name but a few other mighty ancient structures.
Historical use, in Britain, is however far, far more recent. It is commonly believed that hard-fired bricks here were first introduced by the conquering Romans. These were mainly flat, broad thin sections, not unlike a tile, which is probably why they ‘burnt’ so well, to the last the rigors of the Centuries. The smallest 1 ft. sections were known as Bessalis, the largest two foot square as Bipedalis and the ones between Sesquipedalis. Indeed, it is thought that it was only in the 1400’s that the word ‘waltyle’ (wall tile), was replaced commonly by that of ‘brick’, when Flemish refugees began to settle here. There is little-recorded documentation why the art vanished with the withdrawal of the Roman Legions, but the fact remains that British brick making went into decline for nearly 600 years. Some believe that it only began to re-emerge when recycled Roman ‘wall tiles’ became exhausted.
There are examples of brick use dating to the 12th and 13th centuries which include the Tower of London, but it is possible these materials originated in Europe, having been brought here as ballast in sailing barges. Later again English Knights fighting abroad in France sometimes occupied brick forts and recognized their superiority. It is held this directly led to the construction of Tattinshall Castle (Lincolnshire 1431), Caister Castle (Yarmouth 1432) and Herstmonceux (Sussex 1445). However, there had also been earlier influence due to the Hanseactic League. Originally this was an association of European merchants, which later formed into a federation of ‘low’ Country and the Baltic States. It then appears that wherever ‘League’ agents settled in England, brick construction flourished, well illustrated in Norwich, Hull and Kings Lynn.
During Tudor times, brick popularity gradually began to grow due to the increasing shortage and cost of hardwood timber allied to the lack of natural construction material such as stone, in many areas. This also coincided with an increasing influx of skilled craftsman from the Continent, where brick use was extensive. For large important properties, the bricks were often made directly on site; the clay excavated from shallow superficial works. The molds to form the brick shape were less than regular in size creating irregularity and the firing was a very haphazard process. The kilns were temporary circular constructions known as “claps” and the principal fuel source ‘faggots’. As there were no means of controlling the fire, extravagant distressed shapes were produced, subsequently necessitating thick mortar joints with a “struck” trowel joint finish. However, the Tudors were imaginative and fond of using the over burnt ends (known as headers), subsequently creating the highly distinctive checkerboard pattern so common in their work. By the mid-1400’s brick was even being used for the construction of Cambridge Colleges including Jesus and Queens. Today Tudor brick skills are probably best remembered for their wonderfully elaborate twisted chimney stacks and molded brick ornamentation. The first brick sizes set by statute were in 1571 and not surprisingly were called ‘statute’ bricks.
By Elizabethan and Stewart times, brick popularity gained notably with the growing merchant class, with significant sites in Southampton, Berkshire, Lancashire, and Derbyshire. However, the Elizabethans were so taken with the trappings of status, that there were strict ‘Sumptuary Laws’. These not only determined what clothes an individual could wear according to their status and profession but also controlled architectural design, style and use of materials. This was still a society where timber construction prevailed and when the brick was used it still remained common for the clay to be dug and fired on site. It is intriguing to imagine the brickyard actually being created for the construction of a single house in isolation, however large it may have been. As such, the bricklayer, wife, and children would all be involved in the family business, moving from site to site, effectively as itinerant artisans, relocating as demand necessitated.
Brick making still remained a very ‘hit and miss’ affair and undoubtedly, many of the worst examples have long since crumbled into the earth whence they came, leaving only the finer holdings for our inspection. As coal was an extremely expensive commodity, wood remained the principal fuel. It is perhaps not surprising to learn that kilns often caught fire and the whole process of manufacture was fraught with difficulty. There was also much mystique surrounding the art. Bricklayers themselves would normally undergo a seven-year apprenticeship and little was known about the skill. That is until the official globe maker to the King, also a printer by the name of Joseph Moxon published “Mechanic Exercises of Handy-Works” in 1678, revealing the mysteries of the bricklayers’ art to the common people for probably the very first time.
Great Fire of London
Another major boost to their use was undoubtedly The Great Fire of London in 1666. This lasted four days and purportedly destroyed 13,200 homes. Subsequent regulation seeking to prevent further tragedy dictated that new houses had to be built of either stone or brick and the expanding artisan class tended to choose the latter; the former still proving too expensive for the common majority. The Georgian era was an age of increasing refinement and consistency. Mold sizes were standardized, there was regularity of color and the manufacturers began to blend clays. Indeed, after The Great Fire of London, it was found, purportedly by accident, that the ash settling in the clay assisted the firing. IE This ‘dunging’ with ash, called ‘Spanish’ for some reason, reduced the fuel requirement (especially expensive coal) and so reduced cost.
Most bricks were laid in Flemish Bond, introduced in 1630 with alternate headers and stretchers in every course, superseding English Bond, which is where there are alternate ROWS of headers and stretchers, although this bond was later to see a re-emergence of popularity in the early 1800’s. The new forms of firing created great heat and those sections at the heart of the furnace, fused together and were known as ‘burrs’. They were still too valuable to be thrown away however and were often utilized as hardcore. Meanwhile, the under-burnt sections, on the outside of the ‘firing’ heap, called ‘chuffs’, were usually placed back into the center or base of the kiln for the next batch. This was the era when skill in the manufacture and subsequent use, began to come into their own.
Prime Minister, William Pitt the Younger cast greedy eyes on the burgeoning industry and in 1784 imposed an outrageous brick tax of half a crown (two shillings and sixpence) per 1,000 bricks. Perhaps this could be put into context by knowing the Mapperley Works, sited three miles from Nottingham recorded the price of 1,000 Commons at 10 shillings, with better-dressed facings 17 shillings. The tax was subsequently increased in both 1794 and 1803 and one alternative material used was the ‘mathematical’ tile formed to appear like the brick. The repressed manufactures reacted by making larger bricks. In turn, Government turned to taxing by volume instead of the number. Indeed I have seen it suggested that the incorporation of the indentation known as a “frog” on the top of the brick (thought to have taken its name from the soft cleft in a horses hoof), was only partly to assist laying and adhesion, but also to reduce the weight of the section and thereby reduce the tax burden.
The real boon, however, came with the Victorian and Edwardian eras. Impressive introduction of regularity, increasing mechanization, quick setting mortars and color standardization was upon us. It was the heyday of brick production but also the time when handicraft became a mechanized industry. Demand increased substantially for hard clays, often mixed with substances such as anthracite, to produce dense bricks for the bludgeoning canal and later, rail expansion program. With the onset of the industrial revolution, the demand for this very basic building material was so great, that commercial necessity dictated the penal brick tax must be abolished. This was regrettably also a time of great exploitation and suffering. Mercantile magnates strove for profitability and very high levels of child labor were utilized because they were dispensable, readily available and oh so cheap. This was at a time when the average worker was expected to produce a quite staggering thousand bricks per day! Once as a young man, I owned a small reclaimed building material yard in Cambridge. Among the thousands of bricks we lifted, we would often find the small imprint of a child’s hand pressed into the top of a white brick, presumably created in the wetting sheds when the clay was pressed down hard into its timber mold. What suffering must those poor children have endured in that hard, back-breaking environment? Occasionally, we would also discover the paw prints of a cat, or other small animals which had presumably passed across the top of the still malleable material, prior to being stacked for the firing.
By the turn of the century, handmade bricks had increasingly given way to machine processing, the use of ‘stiff clay’ and wire cut bricks, where the clay was extruded through a dye. Color and brick choice for important dwellings increasing became a matter of fashion. Quick setting stronger lime mortars were introduced, as were modern efficient ‘down draft’ kilns, instead of inferior open-air stack burnings and ‘updraft’ claps. Subsequent innovation saw the semi-dry production method introduced, initially a disaster in Nottingham, but later successfully adopted at the Carrington Works when it was understood that between 75 and 125 tons of massive pressure were required to form the brick.
By 1889, the Fletton Works were annually producing 155,000 units known as Peterborough Knotts every day from Oxford Clay. Fletton is still a much used modern term for a lightweight common ‘frogged’ brick, commonly mass produced by LBC (the incredibly successful London Brick Company). At that early time this was an extremely interesting innovation as the top 10 foot surface of clay had long since been exhausted, but a much deeper layer (between 30 and 60 feet down), was found to be characterized as having a high mineral oil content, generally as much as 5% to 8%. This carbon content was almost sufficient for the firing without the need for much by way of additional fuel and required virtually no drying.
Meanwhile stiff northern ‘merles’ and ‘shale’s’ (particularly in Lancashire, Yorkshire, and Northumberland) proved ideal for the production of hard engineering bricks, whilst white washed chalk was added to the London clay to produce a good quality yellow brick. Types included the London yellow stock, Staffordshire blues, Lancashire’s Carrington ‘bloods’, Gaults, Tudor reds, Cambridge whites amongst many others. The scale of the manufacture was quite awesome in scale. I find this perhaps best described by relating to sleepy, agriculturally based Suffolk, never best known for its heavy industrial manufacturing, by way of example. In the Burrs, Ballingdon and Bulmer work, all being relatively close to the River Stour, it is recorded that between 1864 and 1866 alone, they transported 3,245,450 bricks downstream to Sudbury. This naturally excludes those bricks for use at the local level. What a massive scale of production! Presumably, they were then going to be shipped to London on seagoing barges, called ‘brickies’; a name which is now commonly given to the skilled site worker.
Regrettably, modern times have been less glorious. Although it is still readily possible to buy handmade bricks of quality, our society tends to deal with mass production, best identified by color regularity, unit conformity, whilst being very cheap. Two horrendously expensive World Wars within thirty-odd years had done their very best to strip our Country of both craftsmen and raw materials. The government was desperate to discover ways to produce quick and low-cost properties. They had to build homes ‘fit for heroes’, properties for the returning veterans and the subsequent population explosions, let alone repair the massive destruction created in blitzed buildings. Therefore style was lost to the functional. Standardization replaced the traditional and bricklaying arts and patterns were lost to the universal, characterless stretcher bond linear with the fast laying of the machine made brick. Indeed, I have read that in April 1927, foreman William Milne’s laid an incredible 1,121 bricks in a single hour. This is put into context by remembering that the highly skilled, adept, Victorian artisan, in an age when perfection was required, would not expect to lay more than 1,500 in an entire working day. Today, to my way of thinking, it is regrettable that the modern brick success story is usually a matter of basic economics, mass production, exacting standardization and rather boring uniformity. So we come full circle, complete, through to this our current age, but what of traditional practice and the manufacturing process for the original warm, rich colored, textured handmade bricks that I love so much? Let us examine that a little more.
Naturally, traditionally, not all clays were as good as others. Many contained too much calcium, magnesium sulfate, salts or similar, which led to cracking, problems with firing and indeed unsightly surface salt leaching, known as efflorescence. The color of the brick was predominately determined by the chemistry of that raw material and the subsequent firing. Once the clay was dug, it was then left to weather through the winter (actually laid down in law by statute 1477). The chemical process it then underwent, during this ‘resting’, is not really understood even today, but it definitely improved the clay. Then, when it was ready to use, water was added again to make it malleable and plastic. Originally, the clay would have been ‘walked’ by ‘puggers’ in channels, in order to puddle the material, which must have gifted the workers the dubious benefit of very smooth skin on their feet. Later this very manual process was replaced by the machined Pug Mill. This was usually a contraption with blades on a central vertical shaft, powered by a horse walking round and round in circles. The clay bereft of stones was fed in at the top and would emerge at the base as a smooth dough mix.
It soon became common to mix two different clays together, one as plastic as possible for ease of use and the other stronger, to offset shrinkage and distortion. This was rolled out into a large lump known as either a clot or walp. In order to prevent it sticking in the mold, it was then dusted with sand and literally thrown into the waiting wood form. After compressing, the surface was then struck off with a timber bat known as a strike, and later a wire bow, prior to the ‘green brick’ being turned out onto a pallet board. Today we often refer to ‘stock’ bricks as a description for quality facings. The stock was, in fact, a wooden board, plated with iron so as to form a detachable base. The height of this could then be varied to vary the thickness of the brick and even incorporate a surface ‘frog’ indentation. The green bricks were then air dried for at least three weeks, in structures perhaps unsurprisingly known as ‘drying sheds, when they could shrink by as much as 12%. Therefore the molds were invariably larger than the required brick size in order to accommodate this. If an old traditional clamp firing was the next process, it would probably have taken place outside, interspersed liberally with layers of wood and coal. The later ‘clamp’ would probably be sited in a long open-sided shed, with a grate formed from previously over-fired burrs covering a coke bed. The outer cake is added last with the irregularity of the burning creating natural variation. Once burnt and the process effectively finished, the expert maker would pronounce judgment by selecting bricks and tapping one against another. The distinctive ‘ring’ produced by the perfect handmade would determine the quality of the finished product.
Brickies and Dockies
Gone are the days when the Victorian foreman, often called a ‘ganger’, donned a bowler hat to mark his importance. However, any University student who has slaved for a bricklaying gang during University holidays, knows that come eleven of the clock, the site brickie ‘guvnor’, lays down trowel, bolster and hammer. He, and perhaps sometimes, she, straightens the lumbar back, created by bending to lay numberless thousands of rectangular, hand-shaped clay units, to signify the first meal break of the day. In East Anglia, the brickie knows this as the time for ‘dockie’.
One thousand years ago, Etheldreda (Aethelthryth), the daughter of Ana (King of East Anglia), daughter to Ecgfrith (King of Northumbria), founded a religious house upon the strange granite intrusion, the large rock, protruding up from the surrounding barren waste water lands known as the fens. This was the Isle of Ely. It was to become the site for the massive, imposing structure, later dominating the flat ridden lands for literally miles around. It was the site for the huge Cathedral, known locally as the ‘ship of the fens’.
This wonderful structure was built of stone and precious little by way of brick. However, with nothing suitable by way of material for the cruciform structure at the local level, massive blocks of stone were shipped from Monastery quarries at Banack, possibly also Ancaster, near Stanford and Peterborough. The heavily laden seagoing Dutch style barges, navigating the treacherous water ridden fen ways also had to accommodate the tides, because this was long before the expansive wetlands were drained and thereby tamed. It is not difficult for those who know the area to imagine the sailed vessels suddenly appearing at the quayside, through the heavy deep dark fogs and mists which beset the area, even now, during winter months.
The laborers would be waiting for the arrival, at the docks. Their first task was to offload the huge stone sections with a simple block, tackle, muscle and sheer endurance. That done the raw material had to be hauled, probably up the most direct route of ‘Back Hill’, to the waiting Masons. Before that task, however, it is said they would sit down and eat the first part of their meal. They sat down on the docks to rest. They would replenish their energies and they would eat ‘dockie’.
Myths and Legions
Once upon a time, I worked as a totally exhausted brick site laborer, praying for the onset of that early luncheon when I could sit and replenish my force. Today, even now, many years later, I still sense some slight hunger pangs preceding the eleven o’clock break.
There are many myths, legends, and anecdotes relating to most other traditional forms of construction, whether thatch, flint oak, elm, wattle, and daub, yet little relating to humble brick and its hardworking craftsmen. However, I for one, choose to believe that this East Anglican bricklayers early repast, the brief break, still called ‘dockie’, is truly the throwback to that earlier time, traveling down and crossing the barrier of a mere one thousand years.
Beautiful historic Old Savannah is the heart of one of the most storied cities in the world, with cobblestone streets, manicured gardens, and oak-shaded parks drizzling with draped Spanish-moss, and for many of its sidewalks and squares paved with rare brick.
The greatest expense you will incur when you do-it-yourself driveway, walkway or patio project is from the brick pavers. Brick pavers come in numerous styles and sizes and typically cost between $.50 and $1.25 per brick, depending on where you purchase them. Next, to the total cost of the brick, the cost of the mortar, the edging, the sand and the gravel is comparatively small.
Step 1: Determine the Square Footage of Work Area
Find out how much square footage you have to cover. Some pavers may measure 3″ by 5″, but don’t count on it. With bricks, especially, much of their charm has to do with the pattern they create. With your tape, measure the width and length of the space to be covered. With odd shapes such as curved areas, the square footage estimation may be rough without resorting to some complex equations. Triangular areas are easy enough. Measure the base and the height of the triangle. No matter the shape of the triangle, those lines will be perpendicular to one another. Multiply them to get the area.
Step 2: Decide Which Size Brick Paver You Will Use
Brick pavers come in numerous sizes. For simplicity’s sake, assume you will use the 1 7/8 x5 inch mortarless paver. The depth is unimportant for this calculation. The length and width and whether you use mortar will affect the price per square foot.
Step 3: Sketch the Pattern
Assuming you will lay out the mortarless bricks in a basket weave pattern consisting of alternating pairs of horizontally-placed and vertically-placed pavers, you have to fit that pattern into your work area. The pairs will be placed side by side width-wise. One pair of each side by side is a total of 8 inches up and down by 16 inches across.
Step 4: Calculate Number of Bricks per Row
Length multiplied by width, that is your total square feet. 12 inches to a foot, 6×12=72 total inches wide. 30×12=360 total inches in length. One set of pairs (2 vertical bricks next to 2 horizontal bricks) equals 16 inches wide, which allows you to place 4 full sets of 4 bricks each across with 8 inches to spare. You can finish off one row with either a vertical or a horizontal pair that perfectly fills that 8-inch space. Thus, one row requires 18 bricks.
Step 5: Calculate Bricks per Column
Knowing there is a length of 360 inches and that a set of pairs lengthwise is also 16 inches, you can fit 22 full sets in one column with 8 inches left over. With 4 bricks per set plus 2 additional bricks, that equals 90 bricks per column.
18 bricks per row multiplied by 45 (22.5, the number of sets of 4 bricks, multiplied by 2 because each row is only 2 bricks wide) rows equals 810 total bricks. Assuming you’ve decided to use the paver that costs $.50 each, that makes a total of $405 for the pavers. Divide that number by the total square footage, 180, and you get $2.25 per square foot.
Your calculations will get more complex if you’re placing mortar in the joints or if there are odd shapes to factor in. This estimation, however simplistic, breaks down the steps similar to your custom project. The variables are the number of bricks per row and column, the price per brick and the total square footage.
Brick in construction plays a vital role. Traditionally bricks were made of clay. The history of bricks goes as far as the beginning of time. These blocks of ancient construction were used by the Roman, Egyptian and Indian civilizations. Interestingly, antique bricks and blocks used in construction by them are still intact and hold the architectural marvels.
Considered environmental friendly as a building material, a brick is general a rectangular block made of clay, shale, slate, concrete, calcium silicate or stone. It is manufactured by mixing sand with water and then pressing it into steel molds. These raw bricks are then heated at a high temperature of 1000° C which provides the strength to the bricks. Bricks are great insulators as well. The interesting thing is brick stores the heat of the sun and transfers it in the room for several hours after the sun has set.
No two bricks look alike in the shape, size, and composition. Blocks are mainly made of concrete. Blocks are larger in comparison to bricks. They come in both solid and hollow format. Blocks are used mainly in load-bearing walls where strength is very important.
There are mainly five types of bricks.
Common Burnt Clay Bricks: This is the most common form of brick used in construction. It is made by pressing raw material in steel blocks and then heating them in the kiln. These are used for general construction work and do not have a special attractive appearance.
Concrete Bricks: These bricks are made of concrete. The colored concrete bricks are manufactured by adding color pigments. It is often used in facades and fences.
Sand Lime Bricks (Calcium Silicate Bricks): This type of brick is made by mixing sand, fly ash and lime followed by a chemical process during wet mixing. The color of this brick is gray. The shape is uniform and has a smoother finish.
Engineering Bricks: These bricks are made by heating the raw material at extremely high temperatures. It has limited water absorption thus useful in locations where water damage can be a possibility.
Fly Ash Clay Bricks: These are made by mixing fly ash with clay and then heating the raw material at high temperature. These bricks have to be manufactured with care as they tend to expand if the raw material has impurities.
There are two main types of blocks that are solid and hollow. The hollow blocks are further divided into 8 different types.
Stretcher block: These blocks are used to join the corners of the masonry. These blocks are generally laid down parallel to the face of the wall.
Pillar block: These blocks are used in case of piers and pillars. They are also known as double corner blocks.
Corner block: These blocks are used at the end of the masonry which can be a window or a door.
Jamb block: These blocks are used at the location where there is an elaborated window opening in the wall.
Partition block: These blocks are used in building partition walls. They have a larger height than breadth.
Lintel block: These are used for the purpose of the provision of beam or lintel beam. It bears the load coming from the top of the structure.
Frogged brick block: These blocks have a frog on the top side. It helps to hold the mortar and develop a strong bond with the top laying block.
Bullnose block: These blocks are similar to corner block but with rounded edges.
Whether you have had your building facade repaired or not, it is essential that any defective brickwork is repaired. This will prevent moisture penetration which is a major cause of mold and mildew. It is just as important to prevent insect, rodents, and reptiles from getting access to the interior seeking a warm and damp place to reside.
Repairing your historic bricks is majorly important not just for your well-being but also for your long-term investment in your property. Another common problem for your brickwork is moisture saturation. This is caused by severe weather, defective guttering or sprinkler systems that have been placed incorrectly. A combination of these things can further aggravate if not be the original cause of these problems.
Antique bricks are considered by many to be the strongest construction materials ever made by man. They have been used since the 1800’s because of their durability and long shelf life they can significantly help in increasing the value of a particular building.
There are certain conditions that can develop with reclaimed bricks due to environmental factors. Common problems like white scum on the bricks’ surfaces, lime and acid staining, frost attacks and breaking down due to the age of the bricks. Unless you want to completely replace the walls you are best off considering brick restoration. There are many professionals that can do this for you. They will examine the damaged areas of your walls and then determine which materials they will need to carry out the brick restoration process.
There are a few things that need to be considered before you actually hire a brick restoration specialist. Make sure the company you are hiring are fully certified and qualified to do the job. Ensure that everything they do is legal and certified by the local council or government. Another point to consider is the cost. Search online and compare the costs of different companies. Check the levels of service they are offering as they will vary in price and service. You need to make sure you get the level of service you need for the right price.
Look for a company that has a lot of experience with historic bricks and masonry work as well as having the right skills, this will make the work easier and faster. Brick restoration is not something you should overlook and you will definitely need an expert to help you restore the beauty of your home.
For the purpose of restoration and new house projects, it is sometimes helpful for contractors and/or homeowners to know the age of the bricks used. Antique masonry bricks have histories that can be traced back to the early 1800’s. There are a couple of secrets to determining the era of materials used in your home or project at hand including some self-inspections techniques as well as some ways to solicit expert guesses.
To begin, examine for surface details. Historic bricks from early construction periods may contain straw or grass marks, will likely have uneven shapes, and will be larger than modern day bricks. Though antique bricks can still be handmade today, they are costly, time-consuming, and otherwise inefficient, so it is likely that these characteristics are those of more historical masonry.
Sometimes just feeling the bricks will reveal some uniqueness that will help verify the era in which it was made. Those made after the sixteen hundreds will have a frog. This is an indentation that was meant to hold the mortar. This feature will be absent on water struck or solid brick which will also be smooth, and uniform reflecting pressed production.
Manufactured bricks, in short, those that are not handmade and therefore more modern, will usually be stamped or otherwise marked with a company name, logo, or location of the quarry either on the frog depression or on the face of the brick itself.
Other tricks to help identify the period in which a brick was made include color and surface textures. If there are variations in color and/or fold lines, there is an indication that a clamp kiln was used. Clamp kilns were used in early manufacturing and this unevenness in hue and texture is a tale-tell sign of the era.
Most modern products are cut from lengthened and pliable clay materials after which they are dried in a closed kiln are nearly two-thousand degrees.
If you are working with an expert like Old South Brick, they can help make your project stand out from the others. However, you can take a sample of the brick to a local masonry yard and solicit expertise in determining the age. They may be able to do a chemical analysis in an attempt to identify its construction process and contained materials.