The call of the wall

Parapet tales

Parapets are the first line of defence of buildings against rainwater. From brick to RCC to grill, architects are experimenting with their design, writes Bindu Gopal Rao.

Parapet walls must shed water away from the building and therefore it is necessary for them to have an external waterproof layer with a drip channel that directs water away from the building's external walls.

“This can be achieved by the conventional method of sloped cement plaster coating the masonry parapet wall. Another effective method is to ‘cap’ the parapet wall with rust-proof metal sheet layer with a drip. The traditional method of providing a tile layer or roof above the parapet may also be adopted if it is suitable for the architectural style of the building. Decorative cornices serve a dual purpose, they also shed rainwater away from walls,” says architect Deepa Bharatkumar.

In traditional homes, parapets were the simple masonry wall itself going upward. In palaces and few public buildings, they are ornate, sometimes with royal graphic symbols in the centre. Parapets are stronger, heavier and a more solid alternative to railings.

“However, parapet walls are slowly getting replaced by metal railings, especially in balconies. Steel being a high embodied energy material, it’s important that we use the material judiciously. Since they are exposed to rains and weather conditions, dampness leads to rusting and hence care should be taken to maintain them,” says B S Harikrishna, a building expert.

Adds Sanjay Puri, another architect, “Parapet walls for balconies and terraces are being done in glass generally since this creates a more open feeling and when one sits in a balcony, the vision is not restricted as is the case with solid brick parapet walls.
“If terraces are large enough, flower beds of 45 cm height along with glass parapets of 90 cm height are designed.”

Aesthetics versus safety

Safety plays a vital role while designing parapets. It is important to realise that they are part of the building elevation and hence, the need to design them aesthetically while being efficient and resourceful in the usage of material and balance the costs.

“A simple design would be to use hexagonal MS bars for the horizontals and make the top MS pipe rail project towards the inner surface of the balcony or terrace by about 3-4 inches so that it becomes very difficult for the child to climb up on the horizontal mid bars.

Because of the inclination of the top rail, they tend to fall back as they climb higher and hence prefer not to try climbing.

The spacing between the mid vertical or horizontal bars also is very important for safety,” explains Harikrishna. The height of the parapet wall is determined by the waterproofing layer on the flat roofs (terraces). “It is important to provide only vertical elements in the metal grilles or wood trellises - otherwise you are unintentionally providing a climbing structure to the parapet wall. In glass parapet walls, the supporting frame can be on the outside so that it cannot be used from the inside for climbing,” says Bharatkumar.

Young children must always be supervised on flat roofs in the interest of their safety. Cut lengths or scrap reinforcement bars can be sensibly used for railings with designs that look subtle and elegant without comprising on safety. “Besides glass, which is most popular, we are also seeing sturdy MS and Stainless Steel (SS) Laser cut jallis in different patterns being used increasingly in newer constructions. They serve the dual purpose of aesthetics as well as privacy. They have to be made in panels and anchored well for safety,” says Shruti Choudhari, a building expert.

Trend check

Glass, metal and GRC (glass reinforced concrete) are used in a number of ways to create parapets nowadays. “We created an interesting solution for a building in Jaipur which has sliding GRC screens at the edge of the balconies to reduce heat, offer privacy and provide security.

These can be completely open, semi-open or fully closed depending upon the occupants. In another project, we have twisted balconies with twisted glass railings,” explains Puri.

Glass parapet walls on roof-tops as well as for balconies provide all the safety one needs and still preserve the view of the outside. Contemporary buildings flaunt their steel-and-glass aesthetics with innovative hardware.“Green (living) roofs are becoming more and more common. Owners are using their roof-tops as additional space for living, entertaining and for growing ornamental and edible plants. For such roofs, the parapet wall may be designed as a planter with a built-in irrigation system. As on-site solar power and wind power generation picks up steam, parapet walls will be used to support wind-mills and solar panels in the future,” says Bharatkumar.

Materials such as toughened glass with a combination of stainless steel supports are also gaining popularity. “Toughened glass with SS members or MS members are generally being used with it being anchored on granite or Italian marble upstands or copings. Toughened glass with sealants anchored to the parapet walls or slabs directly are also being used without vertical supporting members as they give a clean look. Other materials being used are frosted glass, coloured, laminated glass and textured glass,” says Choudhari.

An interesting combination of metal and treated bamboo or wood framework can also act as parapets. “We can create parapets that are designed as planter boxes in masonry which can hold plants along the parapet wall. But care should be taken in the design to drain out murky water without spoiling other walls,” says Harikrishna.

“These days, the trend of having more open and clean parapet walls on balconies are being seen. It is very important not forget the safety part of the parapet which is the basics of its origin. Fixing arrangement of the balustrade which is primarily responsible for providing strength to the parapet is to be properly checked and approved in order to ensure safety. There is an ultra modern way of making parapet wall in complete glass, where glass either rests on the floor or it is fixed from the front with the help of SS screws. In any of these cases height should not be less than 2’6” from the finish floor level,” says another architect Anand Tiwari.