Informal builders provide the bulk of affordable housing and define large areas of our cities. Originally created for those long considered as poor and unable to house themselves, over time the resultant informal housing generally matches higher income standards. This incremental process has been adopted by governments into programmes called 'site and services', focusing on housing and land development, and embracing process as the key. A methodology to capture this process has been developed which offers a base for developing effective policies in supporting the incremental builders.
mp3 iconIncremental Housing – The new site & services - Reinhard Goethert


Dr. Reinhard Goethert teaches at MIT, champions the informal building energy which is defining city growth, and stresses innovative participatory approaches. He directs SIGUS – the Special Interest Group in Urban Settlements, and is the secretarial for the Global University Consortium Exploring Incremental Housing.

His background includes the design of site and services projects, training programs for international development agencies, and community approaches in rebuilding after disasters.  


The rapid urban population surge of the 60s driven largely from migration with resultant massive unauthorized city expansion provided challenges in finding effective housing interventions.  Upgrading programs became widespread despite high monetary and spatial costs. This lecture focuses on a mimic of the informal housing process which offered a direction for policy, adopted in the 70s by development agencies worldwide and known as ‘site and services’. Difficulties and unresolved challenges in these projects ended their attraction and they fell out of widespread use by the mid 80’s. However, as credible studies indicated that urban population growth was expected to double in the next 20 years, a ‘site and services’ approach has again recently become the option of choice for housing intervention as one of the few proactive options available.  After-the-fact ‘catchup’ policy of upgrading communities as the policy choice was no longer seen as sufficient.

Reinhard proposes that to learn from the successful informal developments as seen everywhere around the world, and to tap their energy and resources, is providing a viable affordable option - this pay-as-you-go process is a key way by which families succeed. However, the process takes a long time, with a clear burden on the families.  Safety concerns of proper construction and lack of appropriate skills are challenges to the family-builders, particularly when additionally confronted with effects from global climatic change. Longitudinal surveys of informal areas and the previous site and services projects of the 70s offer a base for understanding the informal process and suggest areas of necessary and successful intervention.

Reinhard argues that the focus should continue the shift to ‘starter core units’ that can be expanded by owner energies, as they provide initial security and a frame for expansion, while also offering a ‘safe room’ for the increasing disasters from environmental change. A wide range of ‘starter’ options are now available to fit specific situations, from single story units to multi-story expandable apartments for increased densities.  Support/guidance for densification of existing housing provides an effective strategy for mitigating expensive urban sprawl. Standards need to be reoriented to reflect and embrace an incremental, pay-as-you go process. Funding support, and technical assistance needs to be reoriented. Infrastructure can also be developed incrementally, to parallel growth and demands at both neighborhood and house scales.


Articles, research by the Global University Consortium Exploring Incremental Housing