Hi Brad,
The term "tace" might well be another Cecil Hewett invention.
Check out his fig no 286 on page 276 of English Historic Carpentry.
He lists 2 examples for this end of tie beam joint but I can add a third which is in the Bishop's Camera roof at Farnham Castle, Surrey and this tie beam has now been dendrodated by Moir with a date range of between 1306 and 1338 (Moir, 2006) which is almost midway between Hewett's proposed date range of 1200 - 1400.
Regards
Ken Hume
