Home Improvement
Painting and Staining
Wood Crafts

Why must exterior house paints be oil-based?


Top Answer
User Avatar
Wiki User
2011-02-13 03:15:43
2011-02-13 03:15:43

Exterior house paints must be oil based because of the weather. If a water based paint is used, the paint will be damaged when it rains. Using a water based paint would be like coloring the outside of your house with washable markers.

Exterior Paints DON'T Have to be Oil BasedThe vast majority of exterior paints are water-soluble. Though water is the carrier, once an acrylic latex paint cures, it is no longer soluble in water, so the notion that it's like a washable marker is ridiculous. In testing, water based paints often outlast oil based paints because they form a non-reacting, flexible covering, while oil based paints are rigid (so they crack with expansion and contraction) and continuously oxidize, leaving a chalky surface.

Oil based paints can leave a nicer finish, particularly when glossy, because they flow better and dry more slowly than latexes. If you already have several layers of oil-based paint on, it's best to stick with it. Other than that, water based paints are better for most applications, interior or exterior.


I am in agreement...No Oil On Exteriors...you can't buy oil-based paint in volume anymore thanks to "o.s.h.a.".

Exterior latexes have elasticity and conform to weather changes. You can buy "Floetrol" if you're having a leveling problem. This reduces the viscocity of the paint thereby allowing it to lay down and self-level. If you're having the same problem with oil, use "penetrol" or "naptha".


In some applications, exterior paints are better!

Don't use latex paint. Latex paints are a marvelous invention for many reasons but, in some applications and under some conditions, gloss and semi-gloss latex paints can develop a "tackiness" that seems to last forever. I painted a garage door with an exterior latex paint over 5 years ago; in the warm weather, I still hear the sound of the tacky paint breaking contact as the door goes up!

The problem is known as "blocking", and can be caused by many factors such as applying an overly thick layer of paint, not allowing adequate drying between coats, reactions between the primer and the finish coat or the temperature at which the paint was applied -- too hot or too cold.

The best way to avoid blocking is to use an oil-based exterior alkyd paint instead. Alkyd paints, which are the top quality oil paints, dry hard, smooth, and do not produce tackiness. There are mixed views among painters on preparation for a latex-to-oil changeover. Oil paint can be applied over latex without priming as long as the environmental conditions are not too demanding. A light sanding OR the use of a "deglosser" such as Wilbond is essential for a firm paint bond. In the case of exterior doors, I vote for (at the least) sanding followed by priming the doors prior to applying the oil. The primer must be an exterior grade and can be either oil- or water-based. Again, there are some strong opinions on using either type of primer. Be sure it is an exterior grade. Under NO circumstances use Kilz, BIN, or any of the other interior primers.

Depending on location of painted surface, wood can become hot enough under exposure to the sun to blister paint and distort certain plastic moldings that some companies use to mount the window glass! This can cause the paint to prematurely fade or appear weathered. In fact, this overheated situation can even cause wood to expand and contract severely enough to cause cracks! And, guess what makes the situation even worse? Dark pain colors!

A final comment concerning blocking: if you are not ready to repaint and you would like to eliminate any tackiness, one method that I have used successfully is to apply auto or paste wax to the sticky area. The wax coating removed the tackiness, though it may have to be repeated occasionally when any tackiness reoccurs.


Related Questions

Exterior house paint does not have to be oil based, in fact, water based 100% acrylic paints hold up to the sun better and are more resistant to freeze-thaw cycles than an oil based paint. Oil based paint will fade much faster than Acrylic paint and will also crack and peel sooner. Oil based paint should only be used on surfaces that are prone to excessive wear such as entry doors or interior woodwork. Exterior hous paints must be oiled because if you paint outside the house with water paint it will begin to fade and was away everytime rain falls

To determine the cost to paint the exterior of a house one must know the dimensions in square footage of the existing structure. The variables would be contrasting trim, one coat coverage, and cost of labor.

I believe that you prime than paint than seal. It depends on the paint you are using and what you are painting A lot of the exterior paints used today don't require any undercoat. However if you are painting over a previously painted surface you must keep preparation in mind.

You have just given a string of names of different paints. It must be obvious what they are made from by the names.

Apply the water proofing exterior walls to save it during the rough weather. Furthermore,

The internal angles of a regular nonagon are 140o, so the exterior angles must be 220o (360o-140o).

To prepare for your house's exterior painting job you need to decide how much paint you need and what color paint you want to use. dutchboy.com/projects/faqs/exterior/index.jsp

An exterior angle of a decagon can have any value in the range (0, 360) degrees - excluding 180 degrees. The only constraint is that the sum of all exterior angles must be 360 degrees.

Unfortunately combining oil and water in paint always results in disaster. Oil based paints must be thinned with solvent. Brushes used to paint oil based paints also need to be cleaned with solvent.

On the front and back of the exterior of the vehicle.

The measure of an exterior angle of a trapezium can have any value in the range (0, 180) degrees. The sum of all four must be 360 degrees, and there must be two adjacent pairs that add to 180 degrees.

NO! An exterior rated primer must be used. Plus, choose a primer that is recommended for the surface you plan on painting.

The sum of the exterior angles of any polygon must be 360 degrees.360/8 = 45 degrees

If interior angle is 165 then exterior must be 15.Exterior angles of regular n-sided polygon = 360/n.As 360/n = 15, n must be 24

Revenue Bills must begin in the House of Representatives.

The sum of the exterior angles of any polygon must be 360 degrees. Subject to that constraint, individual angles can have any measure between 0 and 360 degrees.

Sum of the exterior angles is 360 degrees. So the sum of the interior angles must be 3*360 = 1080 degrees.

If exterior angles are 120 then interior angles must be 60 so you have an equilateral triangle

The sum of all exterior angles of a polygon is 360 degrees. In a regular polygon, all of the exterior angle are equal, so there must be 360/72=5 sides of the polygon, which makes it a pentagon.

must be- 2.0454545 because the question is not right.

All bills for raising revenue must originate in the House.

You must have noticed that once environmentalist types get into power, they will try to ban anything useful.

Sum of exterior angles = 360 degrees. If each one is 15 degrees then there must be 360/15 = 24 of them.

Yes, a Triangle can have 3 obtuse EXTERIOR angles of measure 120ยฐ ONLY in the case of an equilateral Triangle. OTHERWISE, a Triangle always has 2 obtuse Exterior angles and 1 acute Exterior angle.

What type of bill must originate in the House of Representatives?

Copyright ยฉ 2020 Multiply Media, LLC. All Rights Reserved. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply.