Durability · Why Okinawa Spec

The Case for Okinawa Spec
— Our commitment to durability

Within 500 m of Okinawa's coastline, airborne salt is roughly 10–20 times that of Tokyo. Typhoons make direct hits several times a year, sometimes with peak gusts above 60 m/s.
Having watched imported timber-framed trailer homes rot away in five years, Park Homes Okinawa arrived at a steel specification designed for Okinawa.

01
Salt damage protection

Hot-dip galvanizing
— Removing 99.99% of what causes rust

Okinawa's sea breeze is steel's greatest enemy. Ordinary anti-rust paint covers only the surface, so oxidation creeps in through scratches and bolt holes and rust appears within a few years. What Park Homes Okinawa uses,Hot-dip galvanizing, immerses the steel entirely in a molten bath held above zinc's melting point (about 420°C), atabout 450°C, forming an even zinc coating not just on the surface but inside and right through the holes.

Painting, welding or drilling afterwards would damage that coating. So at Park Homes Okinawa wecomplete all frame assembly, machining and drilling first, then take it apart again, transport it to a dedicated plant and hot-dip galvanize it. It means doing the work twice, but not skipping this step is the foundation of 20-year durability.

1
Frame fully assembled
Welding, bolting and drilling 100% completed
2
Taken apart again (doing it twice)← Not skipping this is the point
3
Transported to a dedicated plant
Carried to a plant equipped for hot-dip galvanizing
4
Hot-dip galvanizing
Fully immersed in a 450°C molten zinc bath. A coating forms inside and through the holes
99.99% of rust factors removed → reassembly and shippingA frame that has been through this process keeps standing up to Okinawa's salt
02
Typhoon & storm protection

Wind pressure S-4 or higher / watertightness W-5
— The Okinawa standard, fitted as standard

Window sashes have two performance standards: wind-pressure resistance (S grade) and watertightness (W grade). The Japan Sash Manufacturers Association recommends S-4 or higher in typhoon-prone regions. Typhoon No. 15, which caused severe damage in Chiba Prefecture in 2019, had peak gusts of 57.5 m/s — beyond the upper limit of the S-3 equivalent. In Okinawa this can happen almost every year.

Park Homes Okinawa fits every unit withwind pressure S-4 or higher and watertightness W-5 as standard. At no extra cost. What other makers add on as an “Okinawa option” is built in from the start.

S-4or higher
Wind-pressure resistance
(recommended for Okinawa)
W-5
Watertightness
(highest grade)
57.5m/s
Typhoon No. 15, 2019
Peak gust
03
Structure & service life

Timber does not last five years
— which is why we design in steel, for 20 years

After moving to Okinawa, President Sakata watched the imported timber-framed trailer homes he had previously sold deteriorate rapidly under salt damage and typhoons. “Timber does not last five years in Okinawa.” That experience led to the decision to manufacture in-house, in steel.

Today Park Homes Okinawa builds every unit withsteel framing, designed for a 20-year real service life. Only when hot-dip galvanizing, S-4-or-higher sashes and the Okinawa-spec design philosophy come together does that 20-year figure become real.

Timber frame (imported)
up to 5 years
Ordinary steel frame
up to 10 years
Park Homes Okinawa
designed for 20 years
Reference service life in Okinawa's salt and typhoon environment (our own research)

“Timber does not last five years in Okinawa. Then we have to build them ourselves.”
— with that resolve, he set up a factory in Tomigusuku City.

Hideyuki Sakata / President, Park Homes Okinawa
04
Manufacturing & after-sales

Because we build locally in Okinawa
— peace of mind after delivery too

Craftsmen who know Okinawa's climate inside out build each unit at our Tomigusuku City factory. The biggest benefit of local manufacturing comes after delivery: if something goes wrong, we can respond quickly. Factory viewings are available any time (by prior appointment).

About the factory and viewings

864-14 Onaga, Tomigusuku City, Okinawa 901-0223
People often tell us that seeing one in person changes their whole image of a trailer home.
Viewings are free and by prior appointment. Just get in touch.

Summary
Salt damage. Typhoons. Heat.
A specification that faces all of Okinawa head-on — that is the basis for 20 years.
Hot-dip galvanizing / S-4-or-higher sashes / steel designed for 20 years / built locally in Okinawa
— only with all four does it deserve to be called Okinawa spec.