One of the first things I learned when using bricks is to set up a vertical coursing scale to coordinate the floors, window, Doors and pitched roof, I did it on houses, but I soon learned it applied to almost any other project with bricks as the external finish., It also starrted an onward learning curve for all the other moduler construction materials I needed to learn about.
But for brickwork, It started at the very bottom, by setting the first level, that being the top of the footing, this was a function of the depth of the foundations in relationship to the soil and root growth.
Most Building regulations require a specific depth, but 900mm to top of the concrete as a min is considered a good depth, if the soil is deeper or root growth is still in existance then it might be deeper, the point is to establish the depth so the coursing can be set.
The first level is the finished ground level, this needs to be set so the next level, that being the DPC, can be laid at the corrdct level, that of 150 mm above the external ground level…
This is set by most Building regulations, in the uk, this is 150mm above the top of the ground level, this needs to be set for the entire perimiter of the building, the ground level is rarley flat, as it needs to accomodate the need to drain water away from the building. By the way 150 mm is the level rain can bounce to from a hard surface, a gravel boundary adjacent to the wall tends to reduce this, but we still have to maintain 150mm.
Let us now consider the brickwork up to this level. first we need to understand the standard size of bricks and their relationship to both their width, length and height
A brick in the UK is set now, to 215x65x102.5 mm, when used with mortar, which is normaly 10mm a modular relationship exists. between three courses and a brick laid vertical , three courses = 225 mm, which is a single brick laid vertical plus a bed of mortar 225mm
The next modular coordination is the use of blocks a single block is also 3 brick courses, .
So if you want to, and I almost always did, use a block inner skin from the top of the foundations, I just counted three cources on bricks and I new that was one block height.
The next modular link is the setting of the window cill and the door and window head. A door is 2100mm heigh, add to that say 45 mm for the head and the same for the cill I can say the head height will be 2100 + 90 or 2200mm plus some bedding at the bottom for the pdc and a little at the top, for fillting, which equates to 30 courses or 2250mm
We now need to count down from the door hear level to establish the window cill if you take a standard window of 1050 mm this is 18 courses leaving 20,, bor packing and fixing top and bottom.
We now need to set the ground floor height 2300 which allows a standard plaster board to be used. a standard plaster board is 1800 mm long this allows a batton to be set at the bottom to allow the plasterboad to rest on and allow fixing with plaster dabs and screw fixing, the Skirting board can cover the gap at the bottom once the floor finish is applied, allowing some allowance for the contractor.
Floor joists will allow you to set the joist hangers onto a specific course and allow the forst floor windos to be set, again by counting the courses, I alway liked to see about 12 courses or 900 mm from the top of the joisr hanger to the cill, leaving the same size wind opening of 30 cources to take me to the wall plate level , I might want to add two or three courses to allow for a decent facia board detail and roofing gutter detail.
This sets the vertical heights, we now need to set the horizontal dimensions in much the same way, a brick is 215 mm long this plus the 10mm. The difference here is the use of a full brick and half a brick, I always set out with full brick dims leaving the brick layer to sort or the half bricks.
Most of the major UK brick manufacturers produce brick charts for modern bricks, I have my set on both paper and digital pdf.
But, there is always a but, modern modular bricks are quite new, it was not that long ago, when the brick size and coordination was not so modular, each Architect often wanting his own brick size and mortar joint thickness, so if you are working on an older brick building, chaeck the brick size, the mortar thickness and most importantly the coursing over say 10 courses.
And be very carfull when attaching newn brickwork to old, my last article touched on this slightly, but I did not mention the problem of trying to line up windows and door heads between old and new, I had to do this once and relied on an old and very experience brick layer to feather courses so the two matched, more of less. if in doubt visit site and find the bricklayer who is going to do the work, and talk the problem through, odd are he or she has already done it.
Modular coordination is common through out construction projects, from brickwork, to curtain walling, to kitchen units, to tiling, and will be covered in more detail in the Mitchells Construction set of book revisions to Book 3: External Fabric Materials & Components and Book 4: Internal Fabrics Materials Finishes & Components.
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