Palm fronds are an economically sound, environmentally friendly and renewable source of building material. With correct construction, palm thatch can last upwards of five years and requires little upkeep. As a roofing material, palm thatch provides great insulation to keep cool on hot summer days, strength to withstand wind, and waterproof durability against temperamental rain. It is natural, easy to use and relatively inexpensive. As with all building projects, this project is best done in fairly dry, warm weather.
Lay out your palm fronds and split the fronds down the spine using a machete or large blade. Cut all the way to the edge and place the right side of the frond in a separate pile from the left side. Keep the halves face up (like they are found on the tree).
Tie same-side fronds together in pairs. Take two right-side fronds tied together and climb to the lowest part of the roof. Affix the paired frond horizontally along the roof beam with string, so that the spine of the frond is sideways when viewed from inside. Repeat this step with the fronds all the way around the lowest layer.
Grab paired left-side fronds, following the same seam, and tie them to the previous layer so that the leaves are hanging in the opposite direction, at a diagonal to the first layer of palms, while still laying perfectly horizontally.
Affix right-side pairs above the spine of the previous layer so that there are no gaps between the spines. Tie with string and repeat for the entire layer. Repeat with the left-side fronds. Keep all fronds facing up.
Tie in double layers of alternating left and right fronds until you reach the top.
Remove leftover palm leaves from the spines and weave them, intersecting over and under, left and right, to form a braided mat of leaves that looks like a checkerboard when done. Create several (upwards of five) mats and lay them on top of each other and tie them together at all four edges, so that each mat is several layers thick. This will act as a roof cap.
Once you have your braided thatch roof cap, apply it to the very top of your thatched hut and secure it.
Palm fronds are completely waterproof when they are an inch thick. If you want to thatch your roof with a second layer, you can, but it is not necessary to do so. For a more finished look, trim the overhanging edges of the thatching just a bit so that doorways or windows are not blocked.
The very top part (the roof cap) of the roof should be the thickest part because structurally it is the weakest and most leak-prone area.