By 1780 the building had started its long association with the medical profession:[9] it was home to a family of doctors for about 130 years,[6][10] although it was rented from the estate landowner for the whole time.

He worked on the magazine Punch, which at the time was edited by fellow Crawley resident Mark Lemon, and illustrated Charles Dickens's series of Christmas stories in the 1840s.

The latest version of the masterplan, dated September 2008, recommends that Tree House should be kept, while allowing "justified" alterations or extensions to be made.

[1] Threatened with demolition and replacement by an office block extension in the 1970s, it was instead dismantled, transported to the Weald and Downland Open Air Museum at Singleton and rebuilt there.

[3] The "Crawley Elm" stood immediately opposite; an ancient, substantial tree, it predated the building.

Another 19th-century author of a work about trees described its "tall, straight stem which ascends to a height of 70 feet [21 m] ... [and] the fantastic ruggedness of its roots".

[2][18] The roofline is lower than that of the Great hall section, which is partly covered with slabs of Horsham stone,[18] a material used often in the area.

These issues coincided with the building being designated as within the zone covered by the £700m "Town Centre North" regeneration programme.

In response to a request from the voluntary sector tenants, to provide better accommodation, the Council moved all of the functions previously undertaken in Tree House to a new building (the Orchard) elsewhere in the town centre in November 2006.