Most of us purchase wall putty along with paints. We pay a lot of attention to the paint brand and its specifications. But often, wall putty is bought along with paints without much thought. Usually, a leading name or brand is an assurance that the quality will be good. Not much attention is paid to product specifications and non-product characteristics. Wall putty has various characteristics that can vary from brand to brand. A wrong choice of wall putty can spoil the entire painting work altogether. So, what should you look for before purchasing wall putty?
Some of the important parameters to be considered before choosing a brand of wall putty are listed below.
- Smooth finish: Provides a smooth surface after setting.
- Coverage: Covers high wall area per unit weight.
- Water resistance: After setting, resists spoilage due to contact of water.
- Adhesion strength: Ability to adhere to substrate.
- Compressive strength: Ability to withstand compressive load.
- Breathability: Ability to allow water vapour to permeate through it.
- Packaging Quality: Quality of packaging used.
- Storage: Storage in cool and dry location.
While some of the above characteristics are difficult to measure without actual usage or in a lab, many characteristics can be judged based on wall putty specifications. We recommend that product characteristics that are strongly linked to the application process like workability, smoothness of finish and coverage are best judged by using a sample of material in a trial. Many brands now offer 1 kg packs that can be used for undertaking such trial. Always make sure you do a full trial with two coats. You and your painting contractor should be able to judge aspects like workability, coverage and finish by using the sample material. Customers requiring ‘whiteness’ can also check it after using a trial pack.
There are other important product characteristics of wall putty that are not easily observable on site. These are tensile adhesion, compressive strength and water resistance. Typically, Indian manufacturers reference themselves to standards of Housing & Development Board, Singapore. For these characteristics, one would have to rely on the specifications mentioned on the bag or manufacturer website. Large users can also choose to get products tested independently on their own. Testing should be done only at reputed facilities. Ideally, multiple tests should be done in independent labs and an average figure arrived at, excluding outliers.
Tensile Adhesion: Should be >= 0.8 N/mm2
- Compressive Strength: Should be between 7 to 12 N/mm2
- Water Retentivity: Should be > 95%
- Water Absorption Coefficient: < 1 kg/m2.H1/2
- Workability: Initial Setting Time of >= 100 minutes and Final Setting Time of <= 500 minutes
Coming to non-product factors, always prefer manufacturers who use good quality impermeable packaging. Over time, wall putty tends to absorb moisture from atmosphere, reducing its performance. Good quality packaging ensures that the product is good to use within the indicated shelf life. Further, always prefer retailers or suppliers who store the material in a cool and dry condition. Finally, always look for the manufacturing date on the wall putty bag. Do not buy material that is near or past the expiry date. Typically, wall putty has a shelf life of 12 months.