Civil Engineering Reference
In-Depth Information
thickness of the material to be used for a door jamb. Timber framed walls to be clad in
plasterboard or timber lining will normally have architraves fitted over the junction of
the door jamb to the wall sheeting. Kram
©
walls (see page 120) will have render come up
to the sides of the door jamb, thereby covering the junction of the door jamb to the
frame. For conventional wall lining the door jamb would normally be 19 mm thick while
for Kram walls it will be 35 or 45 mm thick. See Figure 6.2 for calculations of opening
widths for doors and windows.
Actual door width
for example, 820 mm
+
Thickness of door jamb × 2
for example, 38 mm
Clearance between jamb and frame
for example, 20 mm
Total opening width
878 mm
Rounded up to
880 mm
This calculation will need to be made for each door width in the house.
When building a timber frame to receive a window, the opening width is equal to
the overall width of the window plus 20 mm to allow for manoeuvring of the window
during installation.
Figure 6.2
Calculations to establish the opening size required for a door or a window in a wall frame
1. Mark the floor to show the wall positions
Mark on the floor of the house where the walls are to eventually stand. The most common
timber width for timber framed walls is 90 mm so mark two lines on the floor of the
house to indicate the outer edges of both sides of the wall. Measure from the outside of
the floor to the required position on the floor for the wall and mark it with a carpenter's
pencil. Put a mark on the floor representing each end of the wall. This mark should be
made up of two arrows with the angular part of the arrows joining (see Figure 6.3).
The peaks of the
arrows drawn are to
represent the outside
face of the wall. A pair
of arrows will
represent each side of
the wall, one at either
end of the wall. These
marks could be less
than a metre apart or
over 20 metres apart.
The two arrows need
to be joined by a
straight line to
represent the position
of the wall in its entire
length.
Figure 6.3
Pencil markings on the floor to indicate the position of the bottom of a
timber framed wall
