Write-up and Concept Storyboards by Ahanta Ganti
Our senior project lead who strives to work with alternative materials, relates her process of building a timber house in Alibag as a culturally sustainable solution in keeping with the global movement towards timber as a construction material.
Project Build-up Illustration GIF by Tushara M
Model of our project at Awas
In a world full of green-washing, LEED ratings and plug-ins to find sustainable solutions to design briefs, what relevance do back to basics hold? How do you tread gently, in a coastal town with predominantly black cotton soil to avoid concrete mammoths being flumped onto the ground? On a site where 2 trees embrace each other and teach us to grow in harmony, how do you build not only ‘around’ but also ‘with’ the unspoken protagonists of the site?
This was our response to the brief for a retirement home and skill centre in Awas, Alibag, for one of our patrons of design, who we have had the pleasure of working with on 13 projects so far
Image from site at Awas
Over the years, the once quaint coastal town has gained popularity owing to the quick commute by ferry, serving as a get-away destination to the urban dwellers of Mumbai who are tired of the buzzing city life.
The ethos of this project involved legacy, conservation, warmth, simple-engineering and fuss-free living. The brief was to create a compact house that drew inspiration from old Alibag houses and entailed minimal maintenance. Traditionally, the old Alibaug houses followed a double layer of timber columns with masonry walls in between.
Kelkar Wada at Alibag
Following the footsteps of the wadas of Maharashtra that exhibited exuberant timber framework detailing, we explored timber as our structural system. Fascinating as it may seem, this material, while used extensively structurally in erstwhile times, faded to being limited to cladding, flooring & millworks over the last few decades.
Vishrambaug Wada, Credits : Wordpress
Very little information was available out there on the kinds of woods that could be used in a structural capacity. Rising prices of timber, unsustainable forestry practices and quicker modern construction technologies fuelled this.
Upon research, we came across 3 kinds of wood that held potential to be used as a structural system : Canadian wood, Indonesian teak (bangkirai) and Indian hardwood. Indonesia is known to have vast forests of wood, but due to difficulty in imports, questionable forest management practices and soaring prices, we eliminated this option. We turned to Indian hardwood and explored species like Irul/ Pyinkadu (Indian jackwood) and old Burma teak. However these are more expensive, have higher wastage and there is no centralised agency to overlook the forestation practices, distribution and availability, which made it hard for us to work with it.
Canadian wood on the other hand, had a single entity managing imports, connecting designers to contractors and also providing structural assistance. Certified sustainably managed forests ensured that whatever was being consumed, was also being given back to mother earth. These mainly involved species like Douglas fir & spruce-pine-fir.
We partnered with BuildKraft India, a Delhi based bespoke millwork and contracting team affiliated with Canadian wood, who guided us with our structural grid of 1.5 metres, spanning column free spaces upto 6 metres of depth, vetted by our structural engineer. The timber adopted was Doughlas-fir for the structural system and Yellow Cedar for the doors and windows.
Planks of softwood imported from Canada and transported by sea, were trimmed and glued together under pressure at the BuildKraft India factory. This process is called lamination and it helps to achieve exceptional strength and stability in timber that ordinarily may not be used structurally.
Process of glue lamination (from top left to right bottom): (1) Raw timber planks (2 & 3) Gauging & Planeing (4) Alternating timber grains (5 & 6) Glue laminating (7) Clamping (8) Declamping (9 & 10) Sanding (11) Coating & Staining (12) Finished GLT member
While traditionally local hardwoods were used in India that were more durable, their slow growth rate makes them less renewable and more expensive. Softwoods on the other hand are less dense but grow at a much faster rate, making them a renewable resource when sourced from certified sustainably managed forests. Coupled with technologies such as glue lamination leading to exceptional strengths and higher fire-resistance, softwoods make for better suitors for structural systems in the current times.
Various junctions and joineries between the timber members as well as the timber-to-RCC members were carefully detailed out. A visit to their studio at Delhi to review a 1:1 scale mockup of the same marked the first glimpse of our vision on paper to reality, a truly wondrous moment.
These Glue Laminated Timber; ‘GLT’ sections were transported to site and assembled as a kit-of-parts by a team of skilled carpenters, who ensured every timber member sat snugly into the other, crafting each space at a time.
Joinery Details between : (1) Post and Plinth (2) Post and Beam (3) Post-Beam and Rafter
A hybrid structural system was adopted with RCC upto the plinth to combat the sludgy black cotton soil, upon which 25% of the structure that comprised the first floor with a terrace embraced R.C.C, while the remaining 75% took up the timber post and beam structure.
In keeping with the narrow timber sections, we were looking for a lighter walling material that could remain exposed. Thus a dry walling system was adopted, where cementitious boards are mounted on a framework of PPGI studs to form a lightweight yet sturdy composite wall. This is a common and popular system in more industrialized countries.
Structural Buildup at Awas
Images from our site at Awas
Sustainable timber with its contemporary technologies of glue and cross lamination are being seen as a highly sustainable future in lieu of concrete and steel. In Europe, multi-storey buildings are being constructed using this material. For us, this was a start in using timber in a residential project along with a dry walling technology. We have also used this in a much more ambitious way for canopies in Palitana which will perhaps be a subject for later newsletters and blogs.
While it is immensely promising, we couldn’t help but wonder how our local woods in India could be explored in the sector of mass timber building. Could there be a possibility to explore glue laminated systems with recyclable woods or local softwoods such as Deodhar, Cheed and Kail ? Could the forestry practices in India promote plantation timber towards a more sustainable construction industry? Would more set-ups for fabrication & lamination across the country make it more accessible and economical? With this aspiration, we hope this technology be embraced far more across the continent for a greener future.