Preparing Exterior Trim for Paint
The wood trim of a house is most susceptible when it comes to damage from sun, rain, and wind. You will need to thoroughly clean, sand lightly and prime the surface. You may also need to scrap, strip, re-glaze, wire brush, fill or caulk the trimmings.
- Scrub away all dirt and chalking paint with a scrub brush an d trisodium phosphate (TSP) solution. Rinse the trim thoroughly, and allow it to dry completely before preparing the surfaces for primer and paint.
- The primer provides a base to which the paint can adhere as well as seals it. Slow-drying alkyd-base primers are recommended. On partially bare wood, apply two coats of primer. Tint the primer with some of the finish color to help with more coverage.
- Sand the fascia with rough to find-grit paper. Remember to use safety goggles and dust mask or respirator.
- Blister the paint with a heat gun, and peel it away with a putty knife. Remember to keep a hose nearby for safety.
- Tap out old window glazing compound that is cracked or brittle.
- Power sand the windowsills with a palm sander, graduating from rough- to fine-grit paper and fill cracks and holes with a vinyl exterior spackling compound, and sand the surface when dry.
- Spread new glazing compound along the window frames at an angle, and let it cure.
Once you’ve done the preparation of the surfaces, protect the surrounding area with thick cotton dropcloths before starting your paint job. Protect roofing or other surfaces that will not be coated by may be splattered with paint by using 3-inch tape.
Always paint in fair (above 50 degrees F.), dry weather as cooler temperatures may cause poor adherence. Start your paint job after the morning dew dries, and stop at least 2 hours before the evening dampness sets in.
Avoid painting in direct sunlight and follow the sun around the house. Do not use solvent-thinned paints to cool surfaces that will be heated by the sun in a few hours as this may cause the paint to blister.
Paint in the following order: the overhangs and gutters, then the main surfaces from the top down, and then the trim. Finish with the shutters, railings, porch, and foundation.
If you plan to paint the trim a different color than the siding, wait until the siding has completely dried before beginning the trim. Apply masking tape to protect the siding from the trim paint, and remove the tape immediately after finishing.
Lastly, paint exterior doors and windows. Use a power sprayer for shutters (remove them first). If you’re using a brush for the shutter, begin at the joints where the louvers meet the frame, then paint the lourve, and then finally the frame itself. Always start painting against the grain and finish by painting with the grain.
Let a wall dry fully before deciding whether touchups are needed. A paint finish often will look patchy or uneven until it has fully dried.
Painting Siding & Trim
- Brush on a coat of primer; tint the primer to a color that is similar to your finish color, for a better finish.
- Begin at the top of a wall, and apply the finish coat. Dip the brush no more than 1 inch into the paint. When painting lap siding, start by painting along the bottom edges of horizontal boards. To prevent drips and lap marks, paint all the way across three or four boards.
- Dip the brush about 2 inches into the paint, and tap it against the side of the bucket to clear paint from one side. Then turn the brush parallel to the ground as you lift it. Press the paint-heavy side of the brush against the surface, spreading the paint in a side-to-side motion on horizontal siding or up and down on vertical siding.
- On windows, paint lightly along mullions, allowing a slight bead of paint to lap onto the glass with a sash brush. Before the paint dries, remove the overlap from the glass with a rag wrapped around the end of a putty knife. Holding it at an angle, pull it along the joint between the frame and the glass. Dry paint can be removed with a razor blade. Always paint perpendicular against the wood grain to get good coverage on the face of the trim. Open an operable window when painting the sash of an operable window, so that it won’t be sealed shut by paint.
Painting Aluminum Siding
- Thoroughly clean the siding by scrubbing it with water and tri-sodium phosphate (TSP) or a non-phosphate detergent and then rinse.
- Allow to dry completely, and then sand any chipped or peeled painted areas so that the surface is smooth. Use a buffing pad to remove any chalk from the surface.
- Prime exposed metal with a high-quality acrylic latex metal primer. Apply one or two coats of a high-quality, 100% acrylic latex paint specifically made for metal siding (satin or eggshell finishes for longevity).
- If possible do the painting on an overcast day; if not, avoid painting in direct sunlight.