Build Wood Fired Water Heater

water heater
a heater and storage tank to supply heated water
Water heating is a thermodynamic process using an energy source to heat water above its initial temperature. Typical domestic uses of hot water are for cooking, cleaning, bathing, and space heating. In industry, both hot water and water heated to steam have many uses.
An appliance for supplying hot water for purposes other than space heating or pool heating.

wood fired
fueled by wood; "a wood-burning stove'
(Wood Firing) Firing by the original fuel, wood, gives a particular quality to the unglazed parts of stoneware and to a lesser extent earthenware. The wood must be absolutely dry. It is usually prepared and stored at least a year in advance.

build
Construct (something, typically something large) by putting parts or material together over a period of time
Incorporate (something) and make it a permanent part of a structure, system, or situation
Commission, finance, and oversee the building of (something)
construct: make by combining materials and parts; "this little pig made his house out of straw"; "Some eccentric constructed an electric brassiere warmer"
physique: constitution of the human body
build up: form or accumulate steadily; "Resistance to the manager's plan built up quickly"; "Pressure is building up at the Indian-Pakistani border"