Primers

Anonymous asked 10 years ago

What is the difference between interior and exterior primers?

2 Answers
MagicDave answered.

Generally speaking, exterior primers have a built-in moisture barrier where as interior primers do not… however there is much more in the way they are formulated… which only a paint chemist could explain…

For example Pigmented Shellac Sealer Primer is excellent for interiors and does provide a moisture barrier but does not hold up for exteriors…

Regular Latex interior primers do not provide any moisture barrier … the same is true for some interior oil primers…

It's best to use a product that qualifies as both and is oil based… Kilz makes one like this… along with Zinzer Cover Stain…

At last… read the product labels…

Crowder Painting answered.

Exterior primers are more flexible than interior primers and have better binding resins. Generally, interior primers are harder but sand easy. Dave is right, go with a good universal primer (interior and exterior), can't go wrong with that combo.