Portable buildings are not necessarily portable in the sense that they will be moved frequently. Rather, they are portable in the sense that they are usually built at one location and then hauled to another location and dropped off or quickly assembled on site. Still, there are times when the portability of these structures can be utilized to move them a few feet to accommodate a new landscaping theme or miles away to a new location.
Plan the Job
Plan the job considering the size of the building, how the building is positioned in the current location and the distance the building is to be moved.
Disconnect or remove anything added to the building that made the building "semi-permanent" as opposed to portable. Disconnect any electric lines or water pipes running to the building. Remove any steps, trellises or other items that were added after the building was positioned at the site.
Empty the building. Even if the move is to be only a few feet, the extra weight of items stored inside can add to the difficulty of the move and place unnecessary strain to the structure.
Check to see if the building was built on skids (think sled runners). Most are, and if you need to move the building only a short distance, say from one side of the yard to the other, the easiest way is to just tow the building on its skids.
Build a set of skids, if necessary. Purchase a pair of 6 by 6 beams the length of the building. Jack up the building off the ground using at least two Hi-Lift jacks (four is better–one for each corner) until the beams can be positioned under the building, then lower the building onto the skids. Use lag bolts to fasten the building to the beams.
Fasten chains to each of the skids, attach the chains to a tow vehicle and drag the shed to its new location.
Long Distance Move
Obtain a trailer with a bed large enough to fit the building.
Position the trailer as close to the building as possible and detach from the tow vehicle so the rear end of the trailer can be tilted down to the ground.
Jack up the building far enough for wooden rollers to fit under the skids. Fairly round chunks of firewood make good rollers.
Attach a come along to the tongue of the trailer and attach chains to the building skids. Connect the hook on the come along to the chains.
Work the lever on the come along, ratcheting and rolling the building up onto the deck of the trailer. Reposition the rollers and adjust the chains as needed. Go slow and steady to do the job right the first time.
Jack up the building once it's completely on the trailer to remove the rollers, then lower until the skids of the building are resting on the trailer deck.
Fasten the skids of the building to the deck using tie-down straps or screws, hook up the trailer and tow to the new location.
Back the trailer to the new location for the building, put the building back on the rollers and slowly move the building to the rear of the trailer until it tilts.
Pull the trailer out from under the building.