How many coats of paint and why?

How many coats of paint and why? 

That question gets asked a ton when I am doing a painting estimate.  It seems that one coat should be sufficient – after all, it’s paint, same color same can from the same store however it isn't quite that simple

  Let’s look at several factors that can affect how many coats of paint are necessary for a perfect paint job.

Painting with the same color of paint

If the walls in a room are currently painted white and you paint them with white again, one coat should be sufficient. However, if the “new” paint is of low quality or has a sheen of any kind it will be difficult to match that same sheen as existing, while it may "cover" your finish would not be uniform

Assuming the walls are clean and not faded a single coat using the same sheen and good quality paint should be sufficient,.

Painting dark over light

Accurately estimating the number of coats you’ll need if you’re going from one color to another can be tricky. Theoretically, when painting a dark color over a light color, a single coat is all you need. But this isn’t always the case. (If ever) 

Some paint shades – for example, pastels, and even some heavier colors like deep red – are what we call low-hide colors. This means they don’t hide previous paint colors, as well as other shades do even when the previous colors are of a lighter tint. Two coats of paint are often necessary when using low-hide colors.

Also, custom-mixed colors and lower-grade paints won’t cover as well as factory-mixed paints, regardless of what shade you’re trying to hide.

Painting light over dark

Obviously when painting a light color, say a creamy yellow, over something like a rich mahogany, a single coat isn’t going to do the job. You might paint four coats, and still, that creamy yellow looks polluted. In this case, you can save time and money by applying a tinted primer before the new paint.

There are many types of primer, but all of them are engineered to neutrally block a current color and provide a surface that will allow the new paint to fully attach and cover. Before selecting a primer, talk with a professional painter or an experienced paint store staff member.