Work at the historic site is on behalf of principal contractor Brooks and Wood Ltd and is contributing towards the new car-park and visitor welcome building that are being created.
Enabling works will supplement the new gateway which will bring the house, gardens, parkland, farm and wider landscape together, highlighting the rich heritage of the destination.
The stately home run by The National Trust opened its doors in the 1970s and today welcomes 300,000 visitors per year.
Visitor numbers can reach up to 1,300 per day at peak times, meaning the existing car-park has been outgrown.
The new parking areas will cater for up to 1800 vehicles, made up of 1400 permanent spaces and 400 temporary grass spaces.
The phased project is anticipated to be complete around Spring 2020.
Michael George, Managing Director of Mick George Ltd said: ‘’The visitor numbers indicate just how popular the destination is, attracting people from near and far. We’re pleased to play a part in improving the experience for all those attending the facility.’’