Decorator pattern for building a complete message

I am writing a tcp socket application in c#.in that,server has to send command to connected client and in turn client return some response. My command format is like

<header><header checksum> <operation type><parameter bytes> <checksum>

.for building command I am using decorator design pattern. Like base command bytes ,after that operation type decorator, then after header, footer decorator, decorator will be called in a fixed sequence, is there any way to fix decorator calling sequence or is there any better method to achieve it.