If your project is small enough, like painting a grille, or touching-up a couple of nail holes, you never have to worry how much paint you would need to buy. Just purchase the smallest pack and you’ll still have some leftovers. When the projects get bigger, you would need to come up with a good estimate. Otherwise, you may end up with way too much, which can be quite costly, or too little, which can be equally costly especially if you have half a dozen workers having an unscheduled "tea-break" while you "top-up".

To calculate the amount of paint required for a particular project, you would need to known basically 2 pieces of information :

1. the area to be painted and
2. the coverage of the paint

How to calculate the area to be painted?

a) Walls - Multiply the length and height of the wall to get the area.

b) Room - Add up the areas of all the walls of the room

c) Doors - Multiply the breath and height of the door and double it (for painting on both sides)

d) Cylindrical Pipes - Measure the diameter and the length of the pipe and use the following formula:

                                   Diameter x Length x 3.14

How do I obtain the coverage of the paint?

The coverage of the paint can be found on the product datasheet (also called technical datasheet or product specification). The way it is presented varies with company. Below is an example of Nippon emulsion paint:

The above shows that the theoretical coverage of this paint is 13 sq m / litre at 30 micron DFT (dry film thickness). In other words, one litre of paint can cover 13 square metres if painted at a dry film thickness of 30 microns.

Putting It All Together

Dividing the area to be painted by the coverage, we will arrive at an amount of paint required in litres. For example, if the area of a room is 48 sq metres and the coverage is 13 sq metres per litre, then the amount of paint needed is 48/13 or 3.7 litres. Add 20% loss factor and you’ll arrive at 4.44 litres. Remember that this is for one coat. Double it if you need to paint 2 coats.

Some Tips and Shortcuts

1) In our local context, a HDB room usually requires one can of 5-litre emulsion paint. Living rooms of 4-rooms and above usually need 2 cans.

2) If you do not have access to datasheets, use 8-10 sq m per litre for emulsion paint and 12 - 14 sq m per litre for oil-based paint. This does not work for industrial paints which can vary quite a lot.

3) Rockstone surfaces would require more paint and may need up to 50% more for rougher grains.

4) If the area to be painted is in square feet, multiply it by 0.093 to arrive at the equivalent in square metres.

Hope this post helps you in calculating the amount of paint needed to get that paint job done. However,  amount calculated can still vary depending on painting technique, equipment used and surface profile.

Hempel Marine Colour Card

I receive many enquiries for Hempel Marine Paint. I have uploaded the colour card for reference. Before that, a brief introduction.

Hempel is one of the top brands in marine coatings. First established in 1915 in Denmark, Hempel has grown into a worldwide leader in marine paints. It has 20 factories worldwide plus 130 stock distribution points, supported by 47 sales offices. In Singapore, Hempel office is located at 25 Tuas Ave 11.

The colour card is a PDF file. You would need to have Adobe PDF Reader installed first. If you do not have the reader, download the latest version here.

  Click here to open the colour card

ICI Paints (now Akzo Nobel) has its own proprietory colour notation for the colours in its colour palette fanbook. Colours present in this range can be produced by ICI’s Dulux Colour Solutions Tinting System. The system can produce the various types of Dulux paints - Pentalite, Pearl Glo, Gloss Finish and Weathershield.

The notation used by Dulux, though different in structure, is similar to the NCS notation (see post)  in its use of hue, chromaticness, and "blackness".  An example of the Dulux notation is shown below:

The colour notation indicates the degree of  hueness, the LRV (Light Reflectance Value), and the chroma value of the colour. 30 BG therefore denotes a colour that is between Blue and Green on a scale of 100. A number higher than 50 means that the colour is closer to Blue while a number less than 50 means that it is closer to Green.

The LRV also ranges between 0 and 100. The bigger the number, the lighter the colour. This number is somewhat similar to the first 2 digits in the NCS notation, which indicates the degree of "blackness".

The last part of the notation is the ‘Chroma’. It is a number between 0 and 999. The chroma of a colour makes the colour either intense or subtle. Therefore, the higher the number, the more intense the colour becomes.

The Dulux colour notation system is yet another type used for specifying colours. I suppose ICI adopted a proprietary system to cater to its strength in colours. Unfortunately, this system, being proprietary, is unlikely to be adopted as industry standard for specification of colours.

I’m pretty excited with the range of Rust Oleum products that is now available here (in Singapore). Rust Oleum is a well known company based in Illinois, and has been a market leader in rust preventive paint since 1921. History has it that a certain Scottish-born seaman by the name of Robert Fergusson accidentally spilled raw fish oil onto his rusted metal deck. The oil stopped the spread of the rust and heralded the birth of rust-preventive paint. I suppose top of his agenda was to remove the fishy smell !

I’ve always liked Rust Oleum’s one-coat solution for rust. However, that’s not what I want to write about here. I would like to shift the focus from their forte and introduce some very interesting specialty paints, of which they have quite a few. Our readers in States or Europe are familiar with some of these for years. For us here, the increasing interest in DIY in recent years makes it worthwhile for local retailers to bring them here. I’ll introduce one in this post, and a few more later on:

Rust Oleum Magnetic Latex Primer

This is an interesting product. You can convert any surface into one that attracts magnets. "What’s the use in that ?" you might ask. Well, with this paint, you can do away with cork boards and post-its for your notices and messages. Neither do you need to worry about damaging your walls with tapes or thumbtacks. Paint it on your doors and walls, and notes can be attached on it with magnets, something which, up to now, you can only do on your fridges.

Like the name suggests, Rust Oleum Magnetic Latex Primer acts as a basecoat. It is dark grey in colour (due to iron content?) and can easily be topcoated with most types of wall paint, and in the colours of your choice. Adhesion is just as good on wood, metal, concrete and plastered walls.

It is recommended to apply 3 thin coats instead of 2 thick ones, with overcoating time of 30 minutes each. One can contains 887 ml of paint and can cover 16 square feet (based on 3 thin coats).

This product and a few of Rust Oleum specialty paints are available in Selffix DIY. For locations, go to:

www.selffix.com

The following are the side labels:

Over the weeks (or months), I’ll introduce a few more Rust Oleum products, possibly a few of the following:

• Glow in the Dark paint
• Reflective Paint
• Stone Creation
• Frosted Glass coating

Feel free to ask a question or share a comment.

Jotun Penguard HB

I was recently asked to specify the paint system for a potable water tank. "Potable water" simply means water that is "fit to drink". The substrate was steel and had not been painted. I used to recommend the Amercoat 395 system, but since I was not sure of its availability, I specified Jotun’s Penguard HB system instead.

The paint system requires :

• the bare steel to be blasted to SA 2.5
• 3 coats of Jotun Penguard HB White
• Special washing procedure prior to usage

This paint system does not require a separate primer, as Penguard HB is self-priming. This is great, as wastage is reduced with only one type of paint. Dry film thickness per coat is 100 microns, with the full system totalling 300 microns. Re-coating time and curing time varies with ambient temperature (see Datasheet).

  Jotun Penguard HB Datasheet

Jotun Special Washing Instructions