The thatch consists almost invariably of fronds of rattan gathered in the adjoining forest. This thatch is made by bending back on the midrib every alternate spike till all the spikes lie parallel. Another way is to cut the midrib in the center at the small end and tear the frond into two pieces. These half-fronds are neither so durable nor so serviceable as if the midrib is left entire. Two, three, or four of these fronds, or double that number of half-fronds, are then superimposed, and fastened to the rafters with rattan in shingle fashion.
In localities where sago palm is available an excellent thatch is made in the ordinary Philippine fashion by sewing the spikes of the frond to a slat of bamboo. It is claimed that this thatch will not last much more than a year, as it is a breeding place for a multitude of small cockroaches that seem to thrive upon it.
In the mountainous districts, where up to a few years ago feuds were rife, it was not uncommon to find houses roofed with big strips of bark, or with shingles of flattened bamboo. This style of roofing was employed as a precaution against the burning arrows used by the enemy during an attack.
There is always an extra layer of leaves over the ridgepole as a protection against the rain. Occasionally a long strip or two of bark is placed as a hood on the ridgepole to help prevent the entrance of the rain during the northwest monsoon, when it comes down in indescribable torrents.
A glance at the illustrations will show better than words can describe the peculiar smoke outlets invariably found in Manóbo houses. They not only afford an exit for the smoke, and admit light, but also permit, during storms, the entrance of an amount of rain that does not conduce to comfort.
THE WALLS
The walls are nearly always in the case of better class houses, light poles of wood or of bamboo, laid horizontally one above the other and tied to upright pieces placed at intervals for their support. In poorer houses palm fronds are tied loosely to a few upright pieces. The eaves project down almost as far as the top of the walls. The latter never extend to the roof, but are usually of such a height that a person sitting on the floor can see between the walls and the eaves the space surrounding the house. It is rare to find boards used for the walls, but, if used, they are roughhewn, and are laid horizontally and edgewise, one above the other. They are held in place with rattan strips.
The space, then, between the top of the walls and the roof is open all around the house and serves as one continuous window that affords more ventilation than light. The purpose of this peculiar arrangement seems to be for defense, for no one can approach the house from any side without being seen, and, in time of attack, it affords the inmates of the house an admirable vantage ground from which to ply their arrows.