Read on Twitter
It took a couple of days, but the NCC says this is the in-progress reconstruction of the former "caretaker's cottage" on the property, derelict since 2008, into a guesthouse for visitors (it's been moved from up the road). The cost is included in the Harrington Lake rehab budget. https://twitter.com/PierrePoilievre/status/1251897292782817280
The NCC has been open about the work on the building (see https://bit.ly/2VQKTfm e.g.). That it was being moved is less obvious. And the labelling of the structures at Harrington Lake is difficult to decode.
The NCC published a big report about the official residences in 2018: https://bit.ly/2RZOu9J If you know what you're looking for, you can find that this structure (the "caretaker's cottage") was, in that assessment, basically rubble.
Depending where you look, the structure is called the caretaker's cottage (above), the farmhouse ( https://bit.ly/2VQKTfm ), the staff cottage ( https://bit.ly/2S1hj5w ).
The job isn't cheap: $2.5 million. In a quick search, I don't believe the structure in question has heritage status (unlike the main house at Harrington Lake).
One other thing: The NCC says all the work at Harrington Lake is on hold due to the pandemic.
