12a, Green Tiles, Green Tiles Lane, Denham, Uxbridge, UB9 5HX

12a is a mid-terrace house in Denham, Uxbridge, Uxbridge (UB9 5HX). It has a recorded floor area of 61 m² (around 657 sq ft), construction records dating it to 1930-1949 and council tax band D. The latest certificate (February 2018) shows a D (score 65), on the cusp of jumping into the C band. The rating has held steady at D across 2 certificates since March 2009. Between certificates, wall efficiency went from Very Poor to Poor, roof efficiency went from Poor to Average and window efficiency went from Poor to Good; while hot-water efficiency dropped from Average to Poor. The recommended improvements would lift it to B (score 82), a 2-band jump. Main heating runs on electricity. At 61 m² this is the 10th smallest of 23 units on EPC record in the building, where floor areas span 45–103 m². The building's EPC ratings span F to C across 23 units on file.

Untraded for 29 years, with the last transfer in November 1997. Only one transfer is on record with HM Land Registry, suggesting it has stayed in the same hands for a long time. Today's modelled estimate of £332,000 sits 309.9% above the 1997 sale of £81,000. On a £-per-square-foot basis, the last sale (£123/sq ft) was about 55.5% below the postcode norm.