All joiners' work that is not framed should be fixed so as to be free to expand or contract.

In boarding generally, this may be effected by fixing one edge, and forming the other with a groove and tongue; or the board may be fixed in the centre, with both edges free.

For example, the upper edge of the skirting in Fig. 17 5 is fixed to the "ground," but the lower edge is free to move, the joint between it and the floor, which would open as the skirting shrinks, being covered by the tongue along the bottom of the skirting which enters the groove formed in the floor. If the skirting board were not thus free to move it would split as it became seasoned.

Again, it will be seen that the frame of the window back (Fig. 175) is free at the lower edge.

The dado in Fig. 163 is also fixed at the upper edge only.

N.B. - In the figures illustrating this section the parts are marked with the following distinctive letters : -

A . .

Architrave.

B . .

Bracket.

b . .

Batten.

da . .

Backing.

bl........

Back lining of sash frame.

bk . .

Blocks or blockings.

br . .

Bottom rail of sash.

bw . .

Weight to balance bottom sash.

C . .

Capping.

c . .

Cradling.

D . .

Dado.

f........

Fillet.

g................

Ground.

H . .

Head of sash frame.

h . .

Hinges.

SS. .

Stone sill.

SL. .

Stone lintel.

SF. .

Solid frame.

sb . .

Sash bar.

sk . .

Skirting.

t . .

Throating.

tl . .

Top lining.

tr . .

Top rail of sash.

ib . .

Inside bead.

il . .

Inside lining of sash frame.

1 . .

Laths.

mr. .

Meeting rails.

ol . .

Outside lining of sash frame.

OS . .

Oak sill.

P . .

Plaster.

Pp . .

Pocket piece.

P ....

Pulley.

pb . .

Parting bead.

ps . .

Pulley style.

psl. .

Parting slip.

RA .

Relieving arch.

s . .

Styles.

SB. .

Surbase.

tw . .

Weight to balance top sash.

WB .

Wood bricks.

wb . .

Water bar.

wp. .

Wood plug.

WL .

Wood lintel.

WiBd .

Window board.

x . .

Wedge.

y ......

Do.

zps. .

Zinc parting slip.

Grounds are pieces of wood nailed to plugs, wood bricks,1 breeze fixing blocks, or slips in the wall, so as to form a firm basis to which the more ornamental portions, such as architraves, linings, etc., may be fixed.

Grounds are used round themargins of openings not only to receive the linings and architraves, but to form a solid finish to the plastering.

1 Wood bricks, slips, plugs, etc., have been described at page 10, Part I.

Mitred or Splayed Grounds have the side next to the plastering splayed or bevelled as shown in Fig. 160, so as to form a key for the plaster and secure the joint. This term is often used for grounds which are of a splayed form in plan, such as that in Fig. 178.

Grooved Grounds are those which have the inner edge grooved instead of splayed, to answer the same purpose, i.e. that of affording a key for the edge of the plaster.

Examples are given in Fig. 161, and several other figures.

When the joint between the ground and the plaster is covered by an architrave, the splay or groove on the edge of the ground is often omitted, as in Fig. 166. It is, however, better to have it, to form a key for and to secure the plaster firmly until the architrave is fixed.