Tips on light fixtures and bathroom renovation…

Architect Navneet Malhotra is a perpetual student. He loves to break myths and unmask the true cause for bad work by constantly sharing experience… “Path to gaining knowledge is through sharing,” is his motto.



Does the colour of indoor lighting impact the colour of a wall? How do I make my dimly-lit lobby look bigger and improve the look of other larger rooms that are flushed with soft winter sunlight? Also, how are LED, CFL and regular filament bulbs different from each other? What do you recommend if cost is not an issue?

Pravesh Mehra, Janakpuri, New Delhi

Firstly, artificial or natural light has a huge impact on the way our eyes perceive colour. Just as bulbs and tubes emit different grades of light, natural light also changes its tone from morning to evening. A given surface will absorb and mix with the ambient light of the room. The final colour seen by our eyes is the one reflected by this surface. While pure white light makes the wall look pale and the space seem sparse and bland, yellow light adds warmth and makes colours appear rich. Both lights play an important role. While yellow light is used extensively in residences and hospitality spaces, white light has been known to comfort the eyes while working for long hours on a computer or reading (which is why it is preferred in most offices, schools and hospitals).

When it comes to your lobby, go for pastel shades on the wall and white on the ceiling if you prefer yellow light. But should you opt for white, use a darker shade of the same pastel colour with healthy doses of diffused ambient lights. Designers often conceal lights in niches and coves in the wall or false ceilings to create an evenly diffused lighting condition that mimics natural light. This illusion of ambient illumination, supported by other spotlights, easily helps to alleviate the dullness of a closed space. Since your house faces south (given that it receives ample sun in the cold months), it should be relatively cool in summer and warm in winter. Therefore, you can safely use almost all dark shades. If you feel you get too much sunlight, you could use cool colours like blue and violet. In rooms with abundant light, you could also try natural tones such as dark green-grey, brown or deep green. Hot colours like red and mauve can be used in rooms that remain cool. Using wall paints with a slight surface lustre would also help in improving the reflectivity index of the light. But before you do that, make sure you level the wall surface with POP (as high-lustre paint accentuates surface irregularities).

Lastly, LEDs have been around for a long time but they have gained popularity in building lighting only recently. They are energy-efficient, robust and long-lasting when compared to CFLs or the traditional incandescent bulbs. If cost is not an issue, then LED becomes the natural choice, provided you find the fixture design of your choice. Currently, the few branded manufacturers who deal in LEDs are primarily focusing on floor up-lighters and false ceilings only. But beware, as some of these simply put their stamp on cheap imported products. Osram is a good, reliable choice. Please refer to the comparative chart for the three types of bulbs. The data marked below is approximate and indicative in nature.

What would be the cost incurred to redo an 8 ft x 5 ft bathroom (completely or partially)? Is it necessary to take the wall tiles right up to the ceiling?

RB Deshpande, Pune

Cost estimation is an important part of deciding on a refurbishment project. Dismantling the floor and wall tiles will set you back by approximately Rs 2,000 to Rs 3,000 lumpsum (LS). Monies for removal of debris can vary, depending on the distance of the site from the dumping ground. But that cost for this will be somewhere between Rs 3,000 and Rs 5,000 (LS). The material required within the WC (water supply and discharge pipes, joints, adhesives, etc) will cost Rs 6,000 to Rs 8,000 (LS). This does not include the cost of material required from the overhead tank or extended length to the manhole. Labour costs for pipes and fixtures for the bathroom (not including shafts) would be Rs 6,000 to Rs 8,000. Waterproofing costs approximately Rs 30 per sq ft to Rs 45 per sq ft, while PCC (subfloor filling) is Rs 20 per sq ft to Rs 25 per sq ft. The cost of wall tiles (considering final quantity + wastage, usual discounts given, tax levied and transportation) is Rs 22 per sq ft to Rs 1,500 per sq ft. Other costs include expenses incurred for mortar and adhesive (Rs 25 per sq ft to Rs 35 per sq ft); labour for fixing tiles (Rs 30 per sq ft to Rs 40 per sq ft); new fittings/fixtures (Rs 8,000 onward); wall and ceiling plaster (Rs 18 per sq ft to Rs 22 per sq ft); painting the wall (Rs 8 per sq ft to Rs 25 per sq ft); miscellaneous fittings (Rs 5,000 to Rs 15,000 [LS]) and false ceiling (Rs 45 per sq ft to Rs 55 per sq ft). Keep in mind that all these costs are ‘cost-to-customer’ and specific to New Delhi only.

As for the wall, ideally the bathing area should be tiled upto 7 ft; the washbasin section upto 3 ft; and the WC area upto 4 ft. Also skirt the perimeter with tiles to avoid mop stains on the wall. The rest is up to your discretion.

What is the type of light fixture and what intensity will achieve the best results for a recessed cove in a false ceiling? Also, how do we maintain this space if the room is not air-conditioned? And lastly, what is the difference between ‘laminates’ and ‘Duco paint’?

Gaurav Sanghvi, Mumbai

Using more than one level of false ceiling and cantilevering the lower level can produce recessed coves or shelves that can house light fixtures. Such coves can be used to produce a shallow, diffused light that can either be used to highlight a certain section of the ceiling or help create an impression of floating levels. As the fixtures used within a cove are hidden from view, most of their light is absorbed by the surrounding surfaces and only a small fraction bounces back down through reflection. Owing to this, LED rope lights do not work as cove fixtures, and LED strips, while they do the job, prove to be expensive. On the other hand, the low-intensity, slim T5 tubes, which are easily available, are inexpensive and have a good energy-consumption-to-output ratio. For a continuous band of light, place all the tube lights linearly with a slight overlap to do away with dark spots. To achieve this overlap, connect each tube with flexible wire connectors instead of the regular rigid end-connector fitting. To avoid overheating of wires, make sure not to connect more than ten to one circuit. Dust accumulation in these niches is a standard problem that is best controlled with periodic maintenance. Use a vacuum cleaner instead of a broom or duster for better results.

As for the difference between Duco paint and laminates — Duco is a unique paint that gives an extremely smooth surface finish. A laminate, on the other hand, is a pre-finished multi-layer decorative skin that is glued to wood with adhesives. Duco requires extensive multi-stage surface preparation and paint application. With each layer, the paint surface improves in both texture and lustre. It is sprayed on the surface using a high-pressure compressor machine. Its ability to achieve a good grip with the undersurface and its robust, long-lasting quality makes it the natural choice for the automotive industry. This quality attracted the interior industry as well. The paint had a flawless finish on organic wood forms that traditional laminates were unable to achieve. The only similarity between the two is that they are both surface treatments and their cost is approximately the same (about Rs 50 per sq ft to Rs 75 per sq ft). Dulux and MRF are the preferred brands in the market.

I live in a barsaati on the second floor. The roof gets is so hot during the summer that even an AC is ineffective. Could you please suggest a cost-effective solution for this problem?

Raghunandan Pandey, Gwalior

Summers in North India are dreadful, especially for small independent residential units with large open terraces (barsaatis). These units are particularly troublesome as their small volumes are exposed to the sun from all sides, including its roof. These small structures absorb sunlight all through the day, leading to a large build-up of heat inside the rooms. As a result of this, one needs to spend a lot of energy to cool them.

You could start by replacing the single glass panes of your existing windows with double glass panels. Also, installing thick drapes on these windows to prevent deep penetration of sunlight would help greatly in insulating the rooms. But do not forget to open the windows in the evening to allow the trapped hot air to escape. Additionally, here are a few options to help minimize heat gain from the roof (which constitutes almost 70% to 80% of the problem). A simple solution is to create a nursery with lots of potted plants on the terrace and covering it with a green perforated cloth fixed at a height of 6 ft to 7 ft. Alternatively, you could shade the severely exposed surfaces with tarpaulin. Make sure the sheet is properly secured and that this enclosure has enough gaps to let the hot air out. A thatched roof erected on bamboo will also have the same effect… and the area could double up as an evening sit-out as well.

You can put earthen pots upside down all over the terrace. The trapped air acts as good insulation. This method blocks sunrays from reaching the roof, but it restricts your usage of the terrace. These solutions are temporary, in that you can remove the green cloth, tarpaulin and the pots in winter.

Yet another way to reduce heat absorption considerably is to increase the reflective index of the slabs on the roof by fixing broken pieces of white glazed tiles or by painting the roof white using waterproof cement paint. Needless to say, the second solution is temporary. Broken tiles, on the other hand, can be embedded in wet mortar and the joints filled with white cement slurry. You can pick up broken tiles from any local tile factory. They’ll probably charge you only cartage.

Finally, you could look at insulating the existing roof from above or below. White elastomeric coating applied on the exposed roof surface and outer walls will increase their reflectivity as well as improve the waterproofing ability of the slab. The estimated life of these products is about ten years.

A slightly more expensive option would be to create a false ceiling in the room. The air gap thus created between the existing roof slab and the false ceiling will reduce heat transfer to a large extent. You can also install an exhaust fan above the false ceiling to remove the trapped hot air in between the two surfaces quickly. You can further insulate the ceiling by fixing 2-inch-thick polystyrene (Thermocol) slabs of 40 kg per m3 density with dash fasteners and chicken wire mesh directly to the underside of the roof slab. POP can then be applied to the underside of this surface such that the wire mesh gets embedded in the plaster. Paint the surface for best results.