Sustainable River Roofing: CLEAR Community Hub’s Renovation

Imagine being cocooned by the long feathery leaves of the nipa palm as you learn about the environment and how you could help clean up the oceans. Visitors to Bale Tau – CLEAR’s community learning and art space – are able to do just that, as they sit under the open sided structure, beneath the dark green and brown woven roofing.

And imagine that this roofing that they learn under has been plucked from the nearby Kanari River, and woven into sheets of thatching which will slowly disintegrate and then be returned to the soil, or else the river, in a perfect example of sustainable building material.



Women’s Business

The nipa palm roofing is woven by local women, who pluck the nipa palm from the nearby river and then flatten it out, and fold it over, and sew these sheets of palm leaves together over a thin piece of bamboo.

Palm leaves must be mature and dry before they are used for thatching. At Bale Tau, the leaves were removed from the palm and left to grow and mature for 3-5 months. When harvesting, only the largest leaves are removed from the nipa palm in order to allow the ecosystems around the nipa palm to remain intact.

To create the roof sheets the leaf blades are removed from the stem and stitched into a thin wooden baton. This baton could be made from the palm itself, or in the case of Bale Tau’s roof, bamboo. In order to make the most durable roof, the leaf blades must be  squeezed tightly and neatly together as they are stitched onto the bamboo. The process of laying the roof is somewhat like tiling, where the mats are tied to the rafters in overlapping layers working from the bottom up.

The sheets are then layered, when installed on a timber frame roof, so that the roofing consists of about five or six sheets of nipa palm. Women in the villages close to CLEAR’s community learning hub, Bale Tau, still earn a living weaving and supplying local houses with this roofing.

But because it is made from the palm leaf and not sealed, this roofing tends to last 5- 6 years. When it is first installed it is a lush green, but after being dried by the sun, it will turn a silvery grey after a few months. Last month we replaced the roof at Bale Tau, 6 years after it was first installed.


Traditional Roofing Across South-East Asia

Nipa palm is a species of palm native to the mangrove forests and estuarine habitats of the Indian and Pacific oceans. It is used across Java, and Indonesia as well as Malaysia and South-East Asia for roofing, as they are readily available, and form a waterproof but ventilated roof, which allows air to flow and the hot humid air of the tropics to escape.

The longevity of the roof depends significantly on the way it is installed. A steep roof with a thick thatch is essential for durability. At Bale Tau the roof structure, made from bamboo, had to be at a 60-75 degree angle so that when the roof mats were installed, rain would easily glide off and not be retained by the leaves.

The leaves are used either in their natural form, as they are cut from the palm, or the leaf blades are made up into mats which are then layered to make a complete roof structure.

The palm’s sap is also used to make a sugary drink and for traditional herbal treatments.

If you travel around Batu Karas and rural Java you’ll still see many homes thatched with this beautiful softly textured thatching.

We chose to use this type of roofing over corrugated or terracotta materials to support the local economy and create a more comfortable environment in terms of ventilation and insulation.