The timber-framed design of flats destroyed in a huge blaze are at the centre of a wide-ranging safety probe, it emerged this week.
About 20 families remain homeless after flames tore through homes in Bennett Close, Hounslow, last Tuesday, damaging the four-storey block so severely that it may have to be torn down less than two years after being completed.
The flats are the latest in a line of timber-framed buildings destroyed by fires, sparking an investigation into the newly-popular building technique.
John Gaffney, station manager at Acton Fire Investigation Unit, said: "There have been a number of fires in timber-framed buildings, particularly blocks of flats.
"Timber burns more readily than brick and both ourselves and the Building Research Establishment are looking into the implications of that."
The investigation will come as worrying news to residents in surrounding homes on the estate, many of which are built using the same technique.
A spokesman for builders George Wimpey said: "We are extremely saddened to hear of the damage caused by the fire, and while there is no suggestion George Wimpey is responsible, we will of course offer the fire authorities every assistance in their investigations."
The cause of last Tuesday's blaze remains unknown but investigators believe a discarded cigarette may have burned through a ventilation cover on an outside wall, allowing the heat to pass up through the building and set the roof alight.
It is just since months since families were evacuated from the same block in the middle of the night after the entrance, where a group of youths had been smoking, caught light.