The sinkhole that opened up in Hemel Hempstead has now been filled with 250 cubic metres of foamed concrete.
Work was carried out at Oatridge Gardens in Adeyfield on Friday and the special type of concrete allows some flexibility, while also supporting the home above it.
Now teams of engineers have moved in to carry out geo-technical probing of the while estate - this is expected to take around a week and involves the drilling of about 60 holes.
The results from this testing will be analysed to identify if any further work is required.
Hightown Praetorian & Churches Housing Association, which part owns the homes, is also working closely with the utility providers to reinstate all of the services to the 48 homes as soon as possible.
Spokesman Emma Crump said: “Hightown’s efforts are being concentrated on supporting the residents with their temporary housing arrangements, and other short term issues. We would like to thank Tesco, Asda and Stevensons School Uniform shop who have supported those residents who have not had access to their homes by providing clothing.”
The people living in 32 homes on the estate have been given the all clear to move back in and those that have chosen to do so have been given electric heaters until the gas supply is reconnected, which Hightown hopes will be next week.
Others have chosen to stay with family or friends and where this is not possible the housing association has arranged hotel accommodation.
Hightown has also arranged a 24-hour security presence on the site.
After weeks of above average rainfall it is thought that the sinkhole was caused by underground chalk mines, former claypits and building homes on sand.
Hightown says the site was thoroughly investigated by home builders the Jarvis Group before building began in 2008 and the piled foundations were designed by a structural engineer taking into account the results of geo-techniocal reports.