Construction Updates

Follow our Tregaron Project!

We are excited to be constructing a science-centric facility on the Tregaron Campus. The new building (pictured above to the right of the Mansion) is the Project centerpiece, but the impact also includes:

  • Reaffirming the School's ongoing partnership with the Tregaron Conservancy
  • Landscape improvements around the campus, particularly around the driveway entrance from Macomb Street
  • New stairs from Macomb Street entrance to campus level
  • Restoration of the four-square garden
  • Green roof on the new building

The new building, Le Centre Brown, will have biology, chemistry, physics and Middle School science labs, as well as work and preparation areas for the labs. There will be project spaces to display work, a design technology lab and a new dining facility and fully-equipped kitchen.

The General Contractor selected to partner with us is MCN Build. The selection was made after a rigorous evaluation process overseen by JM Zell, the owner’s representative firm working closely with our Director of Facilities and Board. We are thrilled to have their partnership in this endeavor. 


With the excavation essentially completed by the end of 2023, a tower crane moved on to campus during Winter Break.

In early January the construction team began to pour concrete footings. Through January and February 2024, the foundations of a structure began to appear. When students and staff returned from Spring Break on April 1, it seemed as if the new structure had appeared out of nowhere. Scroll through the gallery to see more.

In early 2024 MCN began to pour cement supports; this view provides an overlay showing how Lower Level Two will eventually look.

In early 2024 MCN began to pour cement supports; this view provides an overlay showing how Lower Level Two will eventually look.

Before the cement for Lower Level One was poured.

Cement pouring in progressl

More cement pouring in action.

After the cement for Lower Level One was poured.

An expansive view of the site as of mid-April 2024.

Close up for Lower Level One floor.

Wider view of freshly-poured cement.

Aerial view of Lower Level One in mid-April.

A side view to see both Lower Level Two and Lower Level One.

An aerial view of Lower Level One with an overlay of the future spaces.


A significant portion of the new structure will be below grade, requiring extensive excavation and removal of soil. This work began immediately after the end of the 2022–2023 school year.

September 14 Update

The soil removal phase of excavation will commence as of September 15, 2023. Dump trucks will be entering and exiting Tregaron via Macomb Street, as they exceed the weight limit for the stone bridge near the Klingle Road exit. Construction traffic will be managed to minimize disruption and will not coincide with drop off and pick up periods. 

There are cameras in place at the Mansion, on the soccer field, and at the AAA Building, allowing for live tracking of the project. Please be patient as video may take time to load. Below the camera feeds there is a gallery of photos from the project; the gallery will be periodically updated.

Photo of Turf Removal

Goodbye to the old turf! The soccer field will be the primary staging area during construction.

Photo of foundation setting

An auger cast is being placed so a steel pile can be set. Eventually a shoring wall will hold the earth in place so excavation for the foundation can be performed.

Photo of rubble

The old grill area exists no more, but parent grill will continue in a new location.

Photo of former basketball court

The outdoor basketball court is gone, but it will be replaced by a half-size court.

Photo of excavation

Demolition in action.

Photo of demolition

Demolition of the stone wall begins.

A view of the excavation area, looking from the Mansion West Wing, at the end of November 2023.

The excavation area with the Mansion in the background.

A view of the wall that shores up the side of the excavation area.

Another November 2023 perspective of the work in progress.


The Dacha was not original to the estate, but was added by Ambassador Joseph Davies and his wife Marjorie Merriweather Post, who purchased the property in 1940, renaming it Tregaron to honor the Welsh town where Davies' father was born. Presumably as an homage to the time he served as U.S. Ambassador to the Soviet Union, the Dacha was built in 1945 to serve as Davies' retreat.

The Dacha has served a wide variety of purposes over the 40+ years Washington International School has owned Tregaron. Most recently it has provided space for larger groups of students, faculty, and staff to meet. Its new location, in the area to the east of the Mansion Solarium patio, ensures its ongoing integration into campus life in a setting more appropriate to a building of its type.

Work to prepare the site for the Dacha relocation began during Winter Break 2022–2023. The Dacha took its historic roll across campus during Spring Break 2023.

Photo of WIS Dacha

The Dacha was added to this location in the mid 1940s.

WIS Dacha Photo
Dacha Site Prep Photo

The Dacha will travel up this gravel pathway to reach its new home.

Photo of Solarium Patio

Future home of the Dacha, adjacent to the Solarium Patio.

Photo of Crated Statues

The statues have been temporarily relocated to make way for the Dacha.

Photo of Dacha Move Preparation

Fast progress from February 17 to February 21!

Photo of Dacha Move Preparation

Clearing the way for the future move.

Photo of Dacha with Exposed Foundation

Hill no more!

Photo of Side of Dacha

The foundation needs to be exposed so the Dacha can be lifted and moved.

Photo of Site for Dacha Relocation

The Dacha's future home!

Photo of Dacha Chimney Dismantling

The chimney had to be dismantled to facilitate the Dacha's move.

Photo of Raised Dacha

Another view of the Dacha waiting for its move.

Dacha on Platform Image

The Dacha has been raised and is awaiting transfer to a wheeled base.

Dacha Wheels

The wheels used to move the Dacha.

Dacha Moving Photo

Passing by the Mansion on moving day (March 30).

Dacha and Mansion Image

Plenty of room for the Dacha to get by the Mansion.

Dacha Photo

The Dacha is in its new home!

Closeup Photo of Dacha

Close-up of the relocated step is building the foundation walls.

We began to use the Dacha again in March 2024. Interior decor and landscaping will take place at a later date.

Rendering of Dacha Relocation

This rendering shows the Dacha in its new location; the brick exposure on the left is the outside wall of the Solarium

Here's a teaser video of the day before the Dacha's big move.

FUN FACT: The combined weight estimate for the Dacha and the supporting steel used during the move was 135,000 pounds (67.5 tons). If you estimate the weight of an elephant at four tons, moving the Dacha was like moving 17 elephants piled on top of each other!

A several-hour move collapsed into one minute! Click on the video above to see the Dacha move from one side of the Mansion to the other.