CORNERS in brickwork

The techniques involved in making a brick wall turn a corner or to finish with a pier require an understanding of bonding and how cut bricks might have to be used to keep a design symmetrical.

Building walls isn’t simply a matter of arranging bricks in straight lines. You may have to include corners and, when you come to the end of the wall, it must be finished off properly. The techniques for doing this effectively are relatively easy once you know the basis of brick bonding.

Brick bonds are crucial to bricklaying; simply stacking bricks one above the other without any kind of interlocking would neither distribute the weight of the wall evenly nor provide the wall with any kind of strength, however strong the mortar between the bricks. And because the joints line up they would provide a perfect channel for water to get in and wash out the mortar.

The simplest way of bonding is to overlap the bricks, with no vertical joints continuing through adjacent courses. This kind of bonding can create numerous different patterns — some very simple, such as the stretcher bond , others much more complicated and requiring ad-vance planning.

Exactly the same principle applies whether you’re building a wall a half-brick thick (a single line of bricks) or one that needs to be one brick thick (two adjacent lines of bricks or one line laid header on). The difference is that instead of only overlapping the bricks lengthways as in a you can also overlap them widthways. With the for instance, all of the bricks are arranged header on to the face of the wall — and again the vertical joints only line up in alternate courses. In effect, the bricks overlap by half their width.

With any bonding pattern, there may be a need for cut bricks to maintain the bond. This may happen at the end of a wall built in stretcher bond where half bricks (called bats) are needed in alternate courses. It may also occur where a new wall is being tied in to an existing wall.

Similarly, with a wall built in header bond the ends need two three-quarter bricks (called % bats) laid side by side in alternate courses to maintain the symmetry, the overlap and wall thickness. With other types of bond, the number and variety of cut bricks increases. The for instance, alternates a course of bricks laid stretcher face on with a course header face on to make a one-brick thick wall — and it needs a brick cut in half lengthways (called a queen closer) in each header course or two % bats laid side by side in the stretcher course.

Corners in brickwork

When it comes to turning a corner in brickwork (known as a the importance of correct bonding is even more apparent. Without it, you’d be building two walls which weren’t interlocked and so lacking in real strength. In a half-brick thick wall in stretcher bond the corner is easy to make. Instead of cutting bats for alternate courses, a whole brick is placed header face on at right angles to the front face of the wall.

The necessary ‘tying in’ of bricks with other bonding patterns, however, usually requires additional cut bricks and careful planning. In effect, the bond may change when you turn a corner. In header bond for example, which has alternate courses starting with % bats, ¾ bats must be placed header on as well to create the corner. In English bond the stretcher course on one side of the quoin becomes the header course on the other.

The end of the wall

If you’re building a wall as a boundary, or enclosing a corner of your garden, it may have to meet existing walls at one or even both ends. In such situations you have to tie in the bricks with the other wall(s), so this may affect your choice of bond for the new wall — it’s always better if the new matches the old. It also means you have to match levels, and before you lay your first new brick you have to chip out bricks from alternate courses of the existing wall to provide for ‘toothing-in’. Even if you can satisfactorily match the bond pattern, the old bricks may be a different size, so to make a proper connection expect to cut bricks to odd lengths to tooth in. More about this in another section. If your wall comes to a free-standing end you must create what’s called a This requires careful checking for vertical alignment, and needs to be finished off to make a clean, neat face. But it is important to make sure the end is strong enough — and to do this you actually increase the width by a half brick to create a ‘pier’. In effect, instead of cutting a bat to finish off each alternate course, you lay the last brick in alternate courses at right angles to the wall face. By adding a bat next to it you create a squared-off end — a simple pier.

Piers for support

It’s not just at the end of a wall that you may need the added strength of a pier. To give a wall extra support, particularly on a long run, you need piers at regular intervals. For in-stance, walls of half-brick thickness need piers that project by at least half a brick every 1.8m (6ft). To do this in a wall built in stretcher bond, you will have to alter the bonding pattern to accommodate the pier, and add cut bricks to ensure the correct overlapping is maintained. If the wall is over 12 courses high, a more substantial pier is needed: three bricks are placed header on in the first course, and % bats are used on the pier and either side of the middle stretcher in the second course.

One brick thick walls need piers at less frequent intervals — in fact every 2.8m (9ft) — but the pier has only to project by half a brick.

Where piers occur, the foundation must be dug slightly wider at that point (about half a brick wider on both sides and beyond the end of the pier).

Method of building

Planning how you’re going to lay the bricks is, of course, only the theoretical side of brick-laying. In practice, to make sure the wall stands completely perpendicular and the corners and ends are vertical it’s most important to follow a certain order of work. Lay at least the first course of bricks dry so that you’re sure they all fit in. Another big problem is that it is difficult to lay a line of bricks with each vertical joint exactly the same width — an inaccuracy of just 1 mm in each joint between a line of 10 bricks will mean that the last brick at the corner or end will project over the one underneath by 10mm. The best way to avoid this happening is by ‘racking back’ — build up each corner or end first, stepping the bricks upwards and checking the vertical each time. When the bricks reach the required height, start filling in. Any slight inaccuracies can be accommodated by the joints in the middle part of the wall where they’ll be less noticeable as long as you make sure the bricks overlap each other by as close to half a brick as possible.

Making the corner square a

Marking out the corner for the foundation is the first priority— and it’s vital that it is square. Using profile boards and strings is the best way to start. Set the boards for each line of the corner about 1 metre (3ft) back from the actual building line. The strings must cross at right angles (90°) and to make sure that they do, use the 3:4:5 method to make yourself a builder’s square. This is a large set-square made by nailing together three 75mm x 38mm (3in x Ivfein) softwood battens cut into lengths of 450mm (18in), 600mm (2ft), and 750mm (2ft 6in) so that the sides are in the ratio 3:4:5. This is a manageable size but it can be made bigger if you prefer.

Laying out the corner

When you have the profile boards in position, dig the foundation trenches and lay the concrete. Allow it to ‘cure’ for at least 5 or 6 days before laying the first course of bricks. This gives it time to harden properly (although it needs about 3 weeks to reach its full strength). The next step is to mark out the actual building lines on the concrete, again using the profile boards and strings.

Lay the first course of the entire wall, starting at the corner and working outwards first along one wall line and then along the other. In building a half-brick thick wall in stretcher bond it is easy to turn the corner simply by laying two bricks to make a right angle. Check the angle using the builder’s square.

Once the first course is laid, check again with the spirit level to make sure that all the bricks are sitting correctly. Add a little mortar or remove a little from underneath any bricks which are out of true. At the same time, check again that all the bricks follow your building line, and tap them into position if they don’t.

Once this is done you can remove the lines and start building up the ends and corners.

Putting in the piers

If you’re going to need piers at any point along the wall, don’t forget to plan them in from the beginning. In a half-brick thick stretcher bond wall a pier is tied in by two bricks laid header on in alternate courses. The courses in between are not tied in but consist of a single stretcher laid parallel to the wall for the pier, and a bat and two % bats replacing two stretchers in the face of the wall.

A pier at a stopped end in a half-brick stretcher bond wall is made using a stretcher face at right angles at the end. The course is completed with a bat and on the alternate course two stretchers are used parallel to the wall.

Checking as you build

One of the most useful checking tools you can make yourself is a gauge rod and as you build up the corners and ends check each course with the rod to make sure the horizontal joints are consistent. If you’re aiming for a wall of about 12 courses in total, build up the corners and ends to about 6 or 7 courses first before starting to fill in between them. To step the bricks correctly, lay 3 bricks along the building line for every 5 courses you want to go up — so it’s best to start by laying 4 bricks along each side of the corner and in from each end.

Filling in

Once you’ve built up corners and ends properly racked back (stepped with the correct overlap), the rest of the wall can be filled in course by course. Although you can lay the bricks normally, checking each time with the level and gauge, a good tip here is to string a line between bricks already laid at each end, then lay the bricks in between to this line. A bricklayer’s line and pins (the pins are specially shaped to slip into a mortar joint) is ideal, but a string can be hooked around a brick at the correct height and then anchored under a loose brick to give a start line to follow.

If you over-mortar a brick and it protrudes above the level, gently tap it down with the end of the trowel handle and scrape off the excess mortar squeezed out of the joint. If a brick does not stand high enough, remove it and the mortar underneath, then replace it with fresh mortar.

Getting the last brick into the line can be quite tricky and a good tip is to scrape the mortar onto the end of bricks at each side — then squeeze the brick in.

A BUILDERS SQUARE

Essential for checking that corners are 90°, this is simply three pieces of wood cut in the proportions of 3:4:5 (ie, a right-angled triangle). Nail them together with a half-lap at the right-angled corner and with the longest side nailed on top of the other two sides.

WHAT CAN GO WRONG because you didn’t check often enough as the wall was rising. With every course

– use the spirit level.

– use the gauge rod because you didn’t check the vertical with the spirit level. Use it when

– racking back.

– starting a new course because the vertical joints further back along the course were not the same width. So make sure that in each course.

– the joint width remains constant.

– vertical joints line up in alternate courses – use the gauge rod for this.

LAYING TO A LINE

When you build up two corners at opposite ends of a wall, the process of laying bricks in between is called ‘laying to a line’. To fix the line for each course use.

– a bricklayers line and pins.

– twine tied around two spare bricks.

– triangular profile boards (good for beginners as you can see that the courses are rising evenly). —

Lay the first course and add the hearth floor. Add the next 3 courses, leaving a brick loose (unmortared) in the second course to be removed to assist the draught to the fire.

Bridge the fireplace opening with a flat iron reinforcing bar and add the fifth course. Fill the ‘table’ end with rubble and dry soil or sand, tamping it down gently and covering it with coarse concrete about 50mm (2in) thick. Leave this to harden for 48 hours, and add the sixth course of bricks. Lay 11 rows in mortar, then dry-lay 3 further rows and mark the outline of the brick circle on them.

These marked bricks can be cut to shape and laid after the circle has been completed. The circle is formed from whole bricks and wedge shapes cut with bolster and chisel. One part of the circle overhangs the wall, so some temporary propping up may be needed until the mortar has set — about a week, then you can use your barbecue.

Exterior gloss

Based on various resins modified with drying oils, full gloss paints have very good weather resistance. Though mostly thought of as major decorative finish for timber, it can also be used on primed and undercoated concrete, brickwork and building boards. And because it dries to such a hard finish it gives good protection in areas where there’s a lot of airborne dirt.

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