Problems and Fixes - Exterior Paint

This story covers some of the problems you may run into with existing exterior surfaces and how to cure those problems before you repaint.


Exterior paints can exhibit more problems than interior paints because they are subjected to the sun, wind, and weather. Here are some of the most common.


Alligatoring can be caused by:
-- Applying alkyd enamel over a more flexible latex primer
-- Applying the top coat before the primer dries
-- Oil-base paints aging and undergoing temperature fluctuations

-- Remove old paint with a scraper or heat gun. Sand the surface and prime it with high-quality latex or oil-base primer, then finish with a top-quality exterior latex paint.


Chalking can be caused by:
-- Low-grade, highly pigmented paint
-- Using interior paint on an outdoor surface

-- Scrub off as much of the chalky residue as possible with a stiff bristle brush and rinse thoroughly.
-- If noticeable chalk is still present, apply high-quality oil-base or acrylic latex primer, then repaint with a quality exterior coating.
-- If little or no chalk remains and the old paint is sound, no priming is necessary.

Paint incompatibility

Paint incompatibility can be caused by:
--Painting latex paint over more than three or four coats of oil-base paint

-- Completely remove the flaking paint and sand and spot-prime where necessary. Repaint with a top-quality latex exterior or oil-base paint.


Peeling can be caused by:
-- Moisture seepage through uncaulked joints, worn caulk, leaks in roof or walls, or leaks through interior walls to the exterior
-- Poor surface preparation
-- Low-quality paint
-- Applying oil-base paint on a wet surface
-- Earlier blistering of paint

-- Try to eliminate the source of moisture.
-- Remove all loose paint with scraper, sand rough edges, prime, and repaint with a high-quality acrylic latex exterior paint.

Cracking and flaking

Cracking and flaking can be caused by:
-- Low-quality paint with poor flexibility
-- Thinning or spreading the paint too thin
-- Poor surface preparation, especially omitting primer on bare wood
-- Painting in cool or windy conditions, which can make latex paint dry too fast

-- If cracking stops above the substrate, remove loose or flaking paint with a scraper, feather-sand the edges, prime any bare spots, and repaint.
-- If you can see the substrate through the cracks, remove all of the paint, then prime and repaint with a high-quality exterior latex.


Lapping can be caused by:
-- Failure to maintain a wet edge when applying paint

-- Paint from unpainted to painted surface.
-- Plan for interruptions at a natural break, such as a window, door, or corner. Alkyd paints generally hold a wet edge longer than latex paints.

Comments (1)
sisbat1 wrote:

can anyone tell me what difference there is between interior and exterior paint?

12/7/2010 09:44:17 PM Report Abuse
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