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Rooftop Extension Option: Structural Fabric Survey

As part of the initial exploration of options for infill development on the Hemans Estate, the Council has commissioned ground and structural surveys to better understand the feasibility of each of the options under consideration.

One option the Council wanted to investigate further was the potential to increase the height of some of the existing blocks on the estate. Specifically Hunter and Darlington Houses through the possible addition of a further two storeys to the existing structures. the Council needed to commission specialists to carry out tests in order to gain a detailed understanding of the buildings capacity to withstand an extra two storeys and the increased weight and stress to the buildings structure.

In April 2016 Lambeth Council commissioned ESG Limited to undertake a structural fabric survey of two buildings, Darlington and Hunter Houses on the Hemans Estate. ESG visited the site in May 2016 in order to carry out a structural fabric survey of the two buildings in question.

The scope of works instructed to ESG included the removal of samples of concrete and masonry for compressive strength testing and to open up a number of locations within the residential areas to establish construction types within the building.


The buildings, completed in the late 1950's, were constructed of concrete ribs and clay pots, a common technique used throughout this period. ESG were instructed as part of their works to expose areas of the masonry walls and take brick samples for testing.

Samples were taken from a number of sites including internal and external walls, lift shafts and stairwells, roof slabs and balcony's. All tests revealed the structure was in a satisfactory condition throughout.

The results of the compression studies revealed that while the existing structure is in satisfactory the addition of a further two storeys with added weight would mean the building is likely to need structurally reinforcing in order to withstand the significant weight increase on the existing foundations. This was deemed to be too costly for the Council to proceed with and did not offer value for money when viewed relative to the number of additional homes possible.


The Council therefore does not intend to progress with the rooftop extension option outlined to residents previously. The council will continue to progress the ball court option for development with a view to consulting with residents in the near future.