Should you prime a wall that is already painted?

I get this question all the time from a lot of people and today were going to discuss whether or not to use primer. Below you will see a short list when primer is necessary to achieve a good job.

You should prime a wall only on the following cases:

-      If the drywall has never been painted in other words if it’s brand new.

-     For walls that have a oil base paint, because latex paint doesn’t adhere very well to oil paint, now keep in mind that regardless of the job you should always sand the walls with a 100 grit sand paper before you paint or prime any wall, so that the new paint has a good grip over the old paint.

-    For stains on the wall due to water damage, markers or any other kind of stain. For water damage I recommend using either oil base primer or shellac primer (alcohol base), because sometimes if you use the latex primer you would see the stain come back again.

-     If you are painting bare wood, it is always necessary to prime bare wood because you want to make sure that the paint is going to stick well to the wood and also to cover the grains on the wood.

-     If you are painting a surface that is too shiny or smooth, because paint doesn’t adhere too well to shiny and smooth surfaces.

There is no need to prime a wall if they were previously painted, because basically the old paint is your primer, now if you have any of the situations I listed above then, yes! you need to prime the wall before painting.

Selecting the right paint brush for the job

It is very important to use the right paint brush, depending on the task at hand, let’s take a look at the different sizes and shapes that are available.

As far as shape you have the rectangular type and the angle type, sizes vary from 3’ inch down to 1.5’ inch and the materials which they  are made from vary from brand to brand, but the most common types are the chinex/polyester  and nylon/polyester blend.

You may see brushes bigger than 3’ inches at the store, but those are mainly use for stain and polyurethane applications. They are a little to heavy and big for ceilings, walls and trim.

Now let’s say you want to paint a room in your house in which you would do the ceiling, walls and trim. For cutting in the ceilings and walls I like to use the 3’ angle brush if I’m working on a residential setting, however if I’m working in a commercial setting then I’ll use the 3’inch rectangular paint brush, just because it holds a little more paint.

Once you are done with the ceilings and walls we move to the crown molding, doors and baseboard. For this I like to use the 2.5’ inch brush, because it gives you more precision for getting into those tight spaces and also holds less paint which is perfect for trim.

So no matter what the job is, you should always use the tools that you feel the most comfortable with. Also another thing to keep in mind is that as far as paint goes there is latex paint (water-base) and oil base which is no longer  in use for residential applications, so when buying a new paint brush make sure you get the latex type.