Reconstruction after 2011 Flooding – Sindh A DFID-Funded project through IOM with Heritage Foundation
Purpose of presentation <ul><li>Description of the type of re-building work underway (300 already completed) </li></ul><ul><li>A guide to some of the reasons why so many houses were damaged </li></ul><ul><li>And the type of remedial measures that can be taken </li></ul><ul><li>Some innovative DRR / resilience measures </li></ul><ul><li>And how much this costs per house (VfM) </li></ul>
Local people learning to make a ring beam of bamboo and lime-concrete. The Ring Beam
Without a ring beam the heavy girders “point load” onto specific points on the wall causing it to crack, buckle then collapse
This conventional / brick and mortar wall is vulnerable because there is NO ring beam beneath the heavy steel girders!
A typical house in lower Sindh. The top of the wall is not protected by the roof – making it vulnerable to monsoon rain getting in, weakening and eventually causing the walls to collapse. By extending the eaves further out this would be resolved
This house has already been rebuilt – without technical advice so the building is once again vulnerable to collapse in heavy rains. For this reason, technical training is one of the best ways to build resilience to future floods / heavy rains. Training should take place in as many communities as possible, using “hands-on” learning, re-building at least one house properly – as reference for the rest of the community. Rain will flash in here and weaken the wall Point loading by this beam will cause collapse of the weakened wall
A typical roof in lower Sindh: weak and bearing directly onto the walls (& no ring beam to distribute the weight).
An extended eave, built by local people during Heritage Foundation training. This will prevent rain flooding into the top of the wall. The ring beam runs below these bamboo girders , now out of site, covered in earth plaster
Bamboo rafters placed at around 50cm centres on top of the bamboo girders. This roof offers greater structural integrity than the popular model of two steel girders and widely spaced bamboo rafters. It is also much cheaper. Girder Rafter
<ul><li>Bamboo girders in place </li></ul><ul><li>On top of the new ring beam </li></ul><ul><li>Note spacing between girders: 4 per house </li></ul><ul><li>Provides for extra strength of roof </li></ul>
These roofs are far stronger than typical roofs made from steel girders and bamboo poles (partially because of the shorter distances between each girder & rafter). So they can be used as “refuge platforms” in case of future flooding (or to grow food, store stuff, etc.). This is a good example of innovation, building resilience and value for money!
Local kids with architecture students from Karachi who should be proud of their voluntary work within these communities. And Carmen, from UN-OCHA whose coordination facilitated this programme
<ul><li>Lime-rich earth mix increases durability and water-resistance to wall </li></ul><ul><li>Especially at the base where standing water can weaken earthen walls </li></ul><ul><li>Lime bonds with the clay in earth much better than cement </li></ul><ul><li>Lime “carbonates” becoming increasingly harder and more resilient over time </li></ul><ul><li>Unlike cement, lime “self-heals” so small cracks in surface won’t allow water in. </li></ul>Karachi University Architecture student explains the methods and rationale of lime use
Critical DRR measures: house on raised platform, lime-strengthened external plaster, roof protruding over walls with longer eaves than usual
<ul><li>Heritage artisans and architecture student volunteers teach local people how to use lime </li></ul><ul><li>Health and safety measures are important – lime burns! </li></ul><ul><li>Lime is “slaked” with water, in a pit, as shown right, for days in advance; </li></ul><ul><li>Lime is locally available and much cheaper than cement. </li></ul>
Technical training delivered by Heritage staff and volunteers (student of architecture from Karachi)
Proud of their new homes, some people are decorating them – showing their pride and ownership
Experimenting with low-cost bamboo construction for a temporary school based on similar building systems
Yasmeen Lari, co-founder of Heritage Foundation – who have been working with bamboo and lime for 5 years in Kashmir, Swat valley and Sindh
Potential partnership with landowners and businesses <ul><li>The Local landowner (pictured) is very supportive of this project; </li></ul><ul><li>He has stated that he (and possibly other landowners) would be willing to contribute towards the costs of housing recovery; </li></ul><ul><li>Possibly on a match-funding basis: for every one paid for by DFID / others they would pay for another; </li></ul><ul><li>A similar scheme could be put in place for industry or large Karachi-based companies </li></ul>
The critical elements to affordable, flood resistant and sturdy homes: bamboo and lime (also have far lower environmental impact than brick, other timber and cement)
Cost <ul><li>Heritage paid 17,000 PKR per house ($200 / £ 160) </li></ul><ul><li>Around the price of one tent </li></ul><ul><li>5 times cheaper than some reconstruction </li></ul><ul><li>So 5 times more people can benefit if this method is used </li></ul><ul><li>This price possible because people themselves build the walls, using the earth around them, together with some lime. </li></ul><ul><li>Then they learn to build the roof, so they can build that for other people within their community </li></ul>
Annex on house damage <ul><li>Showing different types of houses and how they survived or collapsed </li></ul>
These houses have been in the water for over 3 months – and are still standing. This is testament to the capacity of well-built earthen walls to withstand flooding. As the pitched roofs have sufficient eaves, the top of the walls were also protected, preventing collapse.
In the same community this roof has collapsed. Probably due to poor wall construction and lack of ring beam; water may well have infiltrated through thatch roof into top of wall.
Typical construction technique in many parts of Sindh: walls are built around wooden posts, plastered with earth. These posts should be raised off the ground or placed in a lime-concrete bed to protect them from fungus and rotting.
A reed house from the same community already under reconstruction. This will be covered with mud plaster on both sides of the walls, upon which the roof will be placed. Strategic technical advice provided now could greatly increase the resilience of this building.
This shows how heavy roof beams without a ring beam have caused the walls to buckle and crack. They are also trunks from mature trees – which led to further deforestation in the area, something that should be avoided.