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Case Study:Roofing for a Passive Solar Home

The 70 year old single storeyed flat concrete roofed house “Kayavil House” located at Kollam district, Kerala is transformed into a “Cool Home by Dr. A.S Dili, Professor at Department of Architecture of TKM College of Engineering, Kollam by introducing innovative roof structure. Below are the details of the roof construction.

The project site experiences average annual temperature ranging from 25o to 35o Celsius. Summer lasts from March to May; the monsoon begins by June and ends by August. Kollam receives an annual average rainfall of around 2,700mm.

Technology involved

The house is equipped with an effective passive environment control system which makes the interiors cool in all seasons in the Warm-Humid climate of Kerala. The solution consists of an attic space above the false ceiling (protected with glass wool insulation) which is well ventilated with slits of appropriate sizes protected by steel grills.

Construction Details

1. Construction is started from the roof structure. Trafford shaped, 0.35mm thick powder coated steel sheet roof is supported by two inch diameter G.I pipe pillars of nine feet height.

 

 

 

2. Four inch thick, locally available concrete hollow blocks are used for the construction of walls with M-sand cement mortar. Additionally, 4 inch X 6 inch concrete belts have been inscribed into the walls to add a tie effect to the walls.

 

 

 

3. Stiffness of the wall is related to its thickness. Certain foldings have been provided specially to give stiffness to the walls which are thin. The wall is again plastered with cement mortar to enhance the strength.

 

 

4. Security is ensured by a grill work of 10mm diameter steel bars around the attic space above the external walls.

 

 

 

 

5. A frame work is made with coconut tree wood to provide an access to the attic space. A steel grill door is also given in the security grill work to provide entrance to the attic space.

 

 

 

6. GI frame work for the Calcium Silicate false ceiling is provided on the Veranda space. It is fixed at a height of five inches above the top of the wall to provide the ventilation slit for the attic space.

 

 

 

7. Two inch thick glass wool sheet fixed on aluminum foil is evenly laid on the top of gypsum board.

 

 

 

8. The heat flow through the roof and false ceiling towards the interior is controlled by two inch thick glass wool which is evenly laid on the top of gypsum board.

 

 

 

 

9. Calcium Silicate false ceiling is provided on the Veranda space. It is fixed at a height of five inches above the top of the wall to provide the ventilation slit for the attic space.

 

 

 

 

10. Attic space acts as the passive thermal control system in “Cool Home”.

 

 

 

 

 

 

 

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