The last chance for “scaffold-free” photos and video of the Capitol is approaching, the Architect of the Capitol reports.

Views of the West Front, such as the picturesque scene from the edge of the Capitol Reflecting Pool, will be obstructed in the next few days as crews begin to construct scaffolding from the work platform on the Northwest corner of the building. By the end of March, scaffolding may stretch across the terrace to the roof of the Capitol.

Next up, as crews work to restore the 150-year-old cast iron icon to its original majesty, is a 17-day closure of the Rotunda. Beginning April 12, Capitol tourists will be out of luck if they want to glimpse the famed “Apotheosis of Washington” fresco, depicting President George Washington on his ascent to the heavens.

“I recognize this temporary rerouting of Capitol tours is unfortunate and will certainly cause some disappointment to some,” Architect of the Capitol Stephen T. Ayers told House appropriators during a March 4 panel. “This closure is for the contractor to place a protective canopy that will allow visitors to safely access the Rotunda while the exterior project continues.”

The Rotunda reopens April 28.

During that period, rings of scaffolding will begin to rise from the roof, eventually covering the entire exterior of the outer shell.

The first scaffolding visible from the East Front Plaza is expected as early as May.

For two years, crews will be hard at work repairing some 1,300 known cracks, breaks and missing pieces. In preparation for this phase of the project, Ayers sent teams to New Jersey and Ohio to look at how those states had repaired cast iron Domes topping their state houses.

“We found that they were, in fact, using different repair techniques,” Ayers said. “We spent a great deal of time evaluating those techniques and understanding if we could employ them here, would they be faster, cheaper and ultimately determined that the work that they did is not similar and not an apples-to-apples comparison to the work that we do.”

The biggest challenge in Washington, D.C., is that AOC cannot take cast-iron plates down to the ground for repairs under shop conditions. Instead, workers must keep the historic beacon of freedom intact, and do repairs from 250 to 280 feet in the air. With help from the National Institute of Standards and Technology, the team ultimately settled on mechanical “lock and stitch technique,” rather than welding. It involves drilling out cracks and stitching them together with a series of steel pins.

The next phase of the massive restoration project, estimated to cost $125 million, will be revitalizing the space between the outer shell and inner shell.

For fiscal 2015, Ayers is asking Congress to fund the third and final phase — a complete restoration of the Rotunda — that will restore all visible surfaces in the interior of the Dome back to their original condition.

“Our mission, of course, is to preserve the buildings of the Capitol campus for generations to come so they, too, can marvel at the splendor of the Dome, learn the history of our great nation and watch democracy in action,” Ayers said. “And with your support, we will continue in this stewardship role of our buildings and grounds, to inspire and educate all who visit the United States Capitol.”