The Roof Ridging.

To prevent leakage between the uppermost rows of thatch, a form of ridging had to be devised. This consisted of a nikau sheet plaited in a particular way and termed a page 25tapatu. They are sometimes referred to as tapoki, but like the Maori taupoki, it is a general term for a cover or lid. In Raratonga and Mangaia, the special ridging mat is named au.

Plaiting the Tapatu. A tapatu length is plaited from two leaves, one of which is split down the midrib. The whole leaf occupies the middle position whilst a half leaf is placed on either side in such a way that the midrib strips are to the outside and the leaflets cross those of the middle leaf as shown in Fig. 28.

Figure 28.
Arrangement of cocoanut leaves for plaiting
the tapatu ridging sheet.

Thus the leaflets on the left side of the middle sheet A, diagonally cross those of the half leaf B. on its left, and those on the right cross in a similar manner. We have the crossing elements for a plait naturally provided. The midribs of B. and C. are placed about 10 inches from the midrib of A.

As the sheet is usually turned over when fixing on the roof, theoretically the sheets should be plaited with the under surface (tua) upwards, but no attention was paid to this in the demonstration given to the author. The shiny surface was kept upwards. The leaflets were not opened out but were kept doubled, with the midrib forming the forward edge of the leaflet elements in the plait. The plait was a single check, but sometimes a twilled two is used.

With the butt ends towards the worker, the plaiting commences on the left side of the midrib A. The leaflets from B. are directed towards the right, and consequently it is the alternate sets from B. that are raised and lowered by the left hand whilst the right hand places the appropriate page 26Leaflets directed to the left, namely, those from A., in position. Thus in Fig. 29, the alternate leaflets 1 and 3 are raised by the left hand, whilst the right places the lowest

Figure 29.
Plaiting the tapatu sheet.

leaflet from A. in position. For the next stroke, the other alternates, 4 and 2, are picked up and 3 and 1 dropped, whilst the second leaflet from A. is placed in position. This automatically carries on the check plait.

The procedure is merely the continuation of this check technique, care being taken to maintain the midribs an even distance apart. Where necessary, two leaflets may be run together as a single plaiting element. When a suitable distance has been plaited on the left side, attention is turned to the right.

The right half sheet, which has really not been placed in position at the very start, is now laid parallel. It will be seen that the leaflets from B. overlap beyond the midrib of C. The free ends of B. are simply kept turned back to the left by the left hand, whilst A. and C. are plaited together as in the case on the left and for a similar working distance. For clearness, the end of the leaflets from C. are not shown in Fig. 29.

Another section is done on the left and then the right catches up. With many, this technique is considered sufficient and the sheet is finished off with the ends of the leaflets from B. and C. merely crossing each other in the middle line.

A superior method consists in continuing the check plait over the middle midrib after the leaflets from B. and C. have left the leaflets from A. near the middle midrib. Only page 27two or three strokes are possible, as shown in Fig. 30. This technique gives a much neater and more finished appearance to the sheet. In Raratonga, it was said that this extra

Figure 30.
Plaiting over the middle midrib in the tapatu sheet.

finish was introduced from Samoa. The finished sheet is shown in Figs. 31 and 32. The open part of the sheet at the butt end is, of course, overlapped by another sheet. In making a sufficient number of sheets to stretch along the ridge of the roof this overlap must be allowed for.

Figure 31.
Tapatu ridge sheet as plaited.

Figure 32.
Sheet turned over for fixation.

Preparatory Steps. Before the tapatu ridge sheets are put on, layers of grass known as mata are laid over the ridging. This is to round off the part near the taorangi horizontal pole which rests on the forks made by crossing the kaho above the ridge-pole or tahuhu. In Raratonga a hardy mountain fern called moa is also used.

Attaching the Tapatu Sheet. In the tapatu sheet, the split leaf midribs form the boundaries of the plaited part, but the ends of the leaflets from the middle leaf, as well as from the opposite half leaf, project beyond them. In laying the sheets along the roof ridge, it is usual to turn them over so that the side midribs, B. and C. in Fig. 33 keep

Figure 33.
Tapatu sheet turned over.

page 29 down the leaflets. The middle midrib A is stretched along the top of the ridge, whilst B. and C. come down on either side.

The sheet is pinned in position with wooden skewers named tuawa. These are passed through below the taorangi or takiri kaho, which was specially added to the framework to hold the tapatu sheets in position. The skewer passes through the sheet above the side midribs, Fig. 34. The skewers project beyond the sheet on either side

Figure 34.
Fixation of ridge sheet with tuawa skewers.

to prevent it working over the ends, and the midribs assist in this. The position of the skewers below the taorangi pole effectively prevents the tapatu sheet from being blown off. The skewers are inserted at regular intervals along the ridge, and the projecting ends may be seen on the completed house.