停车棚选钢结构还是膜结构，看起来是“材料选择”，实际上是“成本结构的差异”。两者的价格标签差不了太多，但把五年、十年的维护费用算进去，差距就出来了。

Choosing steel structure or membrane structure for a parking shed may seem like a "material selection", but in reality it is a "difference in cost structure". The price tags of the two are not much different, but when the maintenance costs for five or ten years are included, the difference becomes apparent.

钢结构车棚的“隐藏账单”在维护上。 钢材本身强度高、承重好，但它的天敌是锈蚀。钢结构车棚通常需要涂漆防锈，一般一两年内钢材就会大面积生锈，之后需要除漆、除锈、重新涂漆，这套流程每隔几年就要重复一次。五年下来，维护费用可能接近当初的建造费用。

The 'hidden bill' for the steel structure carport is for maintenance. Steel itself has high strength and good load-bearing capacity, but its natural enemy is rust. Steel structure carports usually need to be painted for rust prevention. Within one or two years, the steel will rust extensively, and then it needs to be repainted, derusted, and repainted. This process needs to be repeated every few years. In five years, maintenance costs may approach the initial construction costs.

膜结构的核心优势是“不锈”。 膜材不与空气发生腐蚀反应，后期基本无需维护费用，设计使用寿命可达15-20年。膜材透光率约13%，对热能反射率高达73%，热吸收量很少，夏天棚下体感温度明显低于钢结构。膜材表面光滑，不易积雪和雨水，重量轻，有助于避免压塌风险。

The core advantage of membrane structure is "stainless". The membrane material does not undergo corrosion reaction with air, and there is basically no maintenance cost in the later stage. The designed service life can reach 15-20 years. The transmittance of the film material is about 13%, and the thermal energy reflectivity is as high as 73%. The heat absorption is very low, and the perceived temperature under the shed in summer is significantly lower than that of the steel structure. The surface of the membrane material is smooth, not prone to snow and rain, lightweight, and there is no need to worry about the risk of collapse.

选型的核心判断是“时间尺度”。 如果只打算用三五年，钢结构的初始成本优势更明显；如果按十年以上的使用周期来算，膜结构的“免维护”属性会大幅摊薄年均成本。停车棚不是消耗品，是基础设施。算账的时候，把“修修补补”的成本算进去，答案才真实。

The core judgment of selection is "time scale". If we only plan to use it for three to five years, the initial cost advantage of steel structures will be more obvious; If calculated based on a usage cycle of more than ten years, the "maintenance free" property of membrane structures will significantly dilute the average annual cost. Parking sheds are not consumables, they are infrastructure. When calculating accounts, including the cost of "repairing and patching" is the only way to get the true answer.