Use a water-base primer on wallboards

The Associated Press
Friday October 13, 2000

Q: I have just finished renovating my living room and am now at the stage where the wallboard work is completed. Can you give me some advice as far as painting is concerned? 

A: Decorating newly finished wallboard can present a challenge for the amateur, because wallboard presents a problem surface for the painter.  

When painting wallboard you are actually painting two materials: the paper covering of the wallboard, and the compound that was used to treat nail or screw heads, seams and corners.  

The paper face has a slightly rough or “calendared” surface, while the taping compound is glass-smooth.  

These two surfaces also present unequal absorption rates, and will soak up paint or primer unequally. 

Because of these problems, wallboard manufacturers have always advised that you use a latex or water-based primer as a first coat on a new wallboard.  

Oil primers may dry slowly, soak into the paper face of the panels, and cause the paper nap to raise.  

Oil primers on wallboard will often cause very smooth spots where there is compound over seams or fasteners, and very tough areas where the nap of the paper has been raised.  

Thus, all wallboard manufacturers and the Gypsum Association, a trade organization that represents all wallboard manufacturers, recommend a heavy-bodied latex paint as a first coat over new wallboard. 

You can find special base coats for new wallboard. It is available premixed, or you can buy the primer in powder form and mix it with water.  

It is cheaper than ordinary primer, and will provide the coverage of primers and sealers, without the disadvantages of either of these two paint products.  

It will seal the surface, and contains enough fillers to act as a primer, so it equalizes the suction on both the taping compound areas and the bare paper areas. 

The Gypsum Association advises professionals to shear coat the entire surface of the wall or ceiling with compound, so no bare paper is left.  

In effect, one just plasters the entire surface with painting compound, so there is no difference in texture between paper and compound.  

However, troweling a complete room can be a messy job if you are not skilled with a trowel, so we advise using a first coat as a wallboard undercoater.  

Once the surface differences have been eliminated with a first coat, you can then recoat with any type of paint finish. 

Q: Can you give me some tips on how to wash painted walls? The walls are painted with white, washable paint. 

A: If you are interested in just cleaning a dirty wall, you can use soap and water. A gentle liquid soap, is good.  

Rub the wall down lightly with a towel or a sponge. Don’t scrub too hard, or you will create a slight gloss by removing the pigment. 

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