Tree House Chhauni, Kathmandu Trihaus Design Studio Nisha Pradhan x Shirshak baniya
26/07/2021
SITE & CONTEXT
The site is located in the core residential area in Chhauni, Kathmandu. The site houses a 1000 sq.ft. office block, 50 years old residence and a garage along with plenty of trees. This place is deliberated as a flexible space that welcomes people of all age groups with a space that caters information, technology, eatery, B&B and work place. Tree house is supposed to be added on to the site along with other built spaces. Tree house is positioned near the access route of the site and this is supposed to be the significant component on the site. This tree house would serve as a vacation space as well as a hangout space. This project is a low budget small scale modular tiny house.
TREE SELECTION
The site had number of trees but the kind of tree and location that would be favorable for tree house was to be chosen. So, understanding the distance among trees and location, two Kapoor trees beside the office block were selected. This would also maintain the concept of core and visual proximity of the site.
Kapoor Tree Mango Tree Pine Tree Bottle Brush Tree
2’-7” CIR. Mango Tree 13’-6” 16’ 4’-2” CIR. Kapoor Tree
4’-5” CIR. Bottle Brush Tree
16’-9”
18’-6”’
5’-2”’
18’-9” 3’-5” CIR. Kapoor Tree 16’-8”
5’-6” CIR. Pine Tree
CIR. - Circumference
CONCEPT & IDEA
An attempt of reflecting respect towards the nature and not neglecting the ordinary was prepared. An intention of giving tree something to itself rather than just always being the one to be taking from it was initiated. However, an effort has been made in creating no hamper, no damage and no suffocation to the tree. The idea of the design is based on tiny house concept in consideration to the current scenario of covid pandemic as well as flood context. This would be habitually contextual enough to fit in any of the future site and can be afforded by the people of all income groups providing comfortable space.
CHALLENGES
The most challenging factor was creating a reliable support that would sustain the tree house with live load. This support must balance the structure without hampering the life of tree itself. Another challenge to the tree house is the possible water leakage around trunk holes because several number of branches cuts through the future roof structure.
CASE STUDIES
Tree House – BALI, INDONESIA In this tree house the expression of integrating architecture and environment is experimented which renders the relationship between space and nature. This successfully highlights the boundless space which has no walls and planes. Springing support system of bamboo is used to balance and transfer all loads of the structure. The admirable part of this tree house is the honest material interpretation along with transparent interaction between indoor and outdoor.
Tree House – BARDIYA, NEPAL This tree house is located at Bardiya National Park. This structure stands with four additional vertical timber supports. It has two floors; lower platform serves as a viewing deck and upper floor houses a private bedroom. As for material, timber is expressed at an extent.
Tree House – GULMI, NEPAL This tree house is purely constructed with metal structure. The idea of a tree house as a viewing deck is on a high demand in Nepal. Thus, the metal becomes the fastest and convenient material to construct. The support system used in this tree house is four vertical metal poles that directly reaches to the ground and transfers the load without hampering and effecting the tree.
Tree House – DHARAN, NEPAL This tree house uses timber, bamboo, thatch and metal pipes as a mixture of material palette. This is a two floored structure serving as a viewing deck in the lower platform and a indoor room in the upper floor. As for the structural system, a careful and efficient use of branches is made. In addition, vertical supports of bamboos are used to transfer the load directly on to the ground.
DRAFT DESIGN
Above is the initial design proposed as per client’s requirement; comprising of two floors, lower floor are being a gathering area catering about 8-10 people efficiently and upper floor being private with a bedroom and balcony. The budget of this design was estimated to NRs 10,00,000 which turned out to be very costly. So, a more simpler, cost effective and flexible design was supposed to be reconsidered.
Another issue of this design was with the supporting structural system. Vertical metal pipes were used to support the structure. But then, what tree was doing there was just standing upright in between the house. Tree was ornamented in this design but it stood as a functionless member. The tree house could still freely sustain without tree, with help of its vertical metal supports. So, several options were exercised in order to provide tree its own role and support.
Several staircase options were iterated. The problem in this staircase was with the load balancing factor. In order to support the inclined staircase member, additional adjustments in the support system had to be done as some portion of its load gets transferred on to the platform.
Spiral staircase was practical in terms of small area coverage, But, to construct this staircase of bamboo, budgeting and time estimation got inclined. So, this staircase option was also eradicated.
This staircase option was practical and comfortable. However, the staircase covered more area at the front. So, decision was made to rotate the single flight staircase in parallel to the platform.
MATERIAL
Bamboo was chosen as an ideal material to this construction considering the cost and flexibility. Bamboo is used in all of the supporting members. Whereas, high density metal pipe is used for circular tie and vertical support, which is braced upon the concrete platform that transfers all loads onto the ground. For walls, two inches bamboo lattice is plastered with mud inside and exposed outside. For roof, bamboo truss is covered with corrugated galvanized iron sheets which is to be covered with four inches thatch. The whole intention of choosing this material palette is to minimize the use of metal to blend the tree house on its natural background.
CONCEPTUAL DESIGN
The structural system was considered in order to redesign the tree house. In the final design, the functions of two floors; gathering space and bed space were minimized in single floor. Furthermore, the spiritual belief of energy flow through the funnel effect was implemented with the use of four way slope roof as per the user’s demand. Multiple design options were exercised and the most simplest one was chosen to develop more. Considering the cost effective scenario, this design was iterated as a modular one. The structural design was further developed and visualized through physical model.
The image left shows the base structure above the ground. Six inch concrete base is formed with four numbers of vertical heavy metal pipe. The concrete base is set six inches below and six inches above the ground in consideration that it would not hamper the root of the tree. Likewise, the vertical supports are placed with six inch of gap with the tree to create a sufficient space for a natural growth. This four vertical members are attached to a circular metal tie. This circular tie helps to support the springing bamboos which holds the tree house platform.
In total, twenty four springing bamboo supports are used to transfer load of tree house on to the ground. These are connected through a fish mouth joint on circular tie and platform. This support varies in the dimension and creates an inverted umbrella like structure.
The area of platform is two hundred forty square foot and lies at a twelve foot height above the ground. Bamboo are arranged in a lattice pattern around the trees which allows sufficient space for tree to grow. This also helps to resist the wind force. The horizontal platform is supported through the springing supports without any connection with tree. The maximum and minimum center to center gap in between lateral bamboos are 1.5 feet and 1 feet respectively.
Access to the tree house, is through single flight staircase made up of bamboos. 20’ x 12’ platform is divided into 12’ x 8’ bedroom and 12’ x 12’ living space. The room has a clear height of seven foot. The outer living space of tree house acts as a space for siting, eating and talking.
The interior space has a king size bed, side table and an open shelf. The window at east allows the user to have a view towards the site. The bed room has the tree trunk penetrating through the floor and roof compelling tree to be interactive and not letting user to forget about being inside a tree house. The exposed bamboo truss and natural material would reflect the minimalistic approach and honesty of the essential natural materials.
The slope of 30 degree is maintained in the four way slope. Roof and truss is supported in corners through three numbers of vertical bamboo posts.
The design could be constructed in three phases as per financial convenience and still continuously be functioning as well. For the first phase, structural support and platform is constructed with required handrails for safety purpose. This space could be used as a casual hangout area. The estimated cost for this phase of construction is around NRs. 2,26,885/(US$1910) (dated 7/13/2021)
For the second phase, roofing is added on the construction. The roof stands upon vertical bamboo supports on four sides that holds the truss and transfers the roof load to the platform. This space can be used as an functional space against rain. The estimated cost for construction up to this phase is around NRs. 2,92,429/- (US$ 2462) (dated on 7/13/2021)
The third phase is the end stage of this construction. For this phase, walls and fenestrations is introduced. So, an interior space is created and hence an indoor and semioutdoor space is expressed. The estimated cost for complete construction is around NRs. 3,28,444/- (US$ 2765) (dated 7/13/2021)
PHYSICAL MODEL
Above images shows the initial phase wise model interpretation of the tree house structure. During the model making process, several necessary and unnecessary structural pieces had been identified and modified. So, the model making and the 3d application software in the design process had a simultaneous relation.
PHOTOGRAPHS
From Left to right: Junior Architect Prakriti Bhandari, Junior Architect Nisha Pradhan, User Bijay Niraula, Senior Architect/Planner Saurav Shrestha during the meeting at site to brainstorm and initiate more collaboration between the expert group and user group for future plan and design.
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