Paint does not last forever. It also has an uncanny knack for making homes look new or old, based on their condition. That is why a relatively new house with peeling paint will look old. It’s while an old home with paint that is in perfect condition may look like it was just newly built.
CRITICAL SAFETY WARNING: If your home was built before 1978, that “peeling paint” is likely Lead-Based. Peeling, chipping, or cracking lead paint creates toxic dust that can cause permanent brain damage in children. Do not sand, scrape, or disturb these surfaces until you have read the EPA Safety Protocols outlined in this guide.
It will all eventually need touch-ups, whether the most expensive kind of paint or only a cheap one is applied. Some will last a bit longer. All will eventually succumb to wear and tear, regardless of surface. And because they are constantly exposed to the elements, the exterior components of any home are typically the first ones to be affected.
Preparing Surfaces
Before you can start applying the first coat to the window frames and sill, you need to prepare these surfaces first. Prep work is important if you want the paint to adhere to the surface and get a smooth finish properly. The kind of preparation needed will depend on the material of your window frames and sills.
1. Protect the Work Zone Don’t forget to keep your floors or the ground protected before starting. Place plastic sheets on the ground directly under the windows you will work on. This is especially critical if your home is pre-1978, as you must catch any paint chips or dust generated during the process.
2. Clean and Degrease (By Material)
- For Vinyl: Clean the surface by applying a degreaser using a sponge or cloth. A solution of water and dishwashing liquid is recommended because it is mild enough to prevent damaging vinyl.
- Solvents: If using chemical removers, ensure they are safe for vinyl (mineral spirits and acetone are generally safe; strong strippers are not).
- Profiling: Use 220-grit sandpaper to lightly sand the surface. The goal is to remove the “shine” so the paint sticks.
- For Aluminum: Use a dishwashing liquid solution to clean the surface.
- Scrubbing: For hard-to-remove dirt and grease, scrub with a semi-abrasive scouring pad.
- Profiling: Remove loose or peeling parts using medium-grit (100-grit) sandpaper. You can also apply a solvent for easier removal. Do not apply primer if the aluminum is still wet.
3. Remove Dust Whether working on wood, vinyl, or aluminum, it is vital to remove all dust present after sanding. If not, expect to see bumps and a rough finish.
- The Tool: Use a HEPA vacuum or a damp tack cloth.
- The Detail: Dust may seem minuscule, but it creates a barrier that causes paint to peel even after applying multiple layers.
4. Mask the Glass Once the surface is clean, dry, and dust-free, cover the glass and nearby structures with newspaper and painter’s tape. This prevents the new layer of paint from accidentally getting on the glass.
- Note: If you have a steady hand, you can leave the glass bare and use a glass scraper later to remove stray paint, but be careful not to scratch the pane.
How to Paint Window Frames and Sills
| Pt. | Steps | Notes |
| 1 | Check for signs of water damage, rot, mold, and mildew. Expert tip: Before uncapping your paint, verify the substrate integrity with a digital moisture meter; if the reading exceeds 17%, any new coating is statistically guaranteed to blister within months due to internal vapor pressure. | |
| 2 | Look for gaps present between the glass and the frames and seal them off using fillers, like acrylic sealants or multi-purpose putty. | Allow them to dry. Patch up any holes in the sill as well. |
| 3 | If you do not want the installed fixtures to be affected by the paint, remove them first. | Maybe you plan to open or close the window while working. Remove all hardware (lifts, locks, pulls) and boil them in a crockpot to strip old paint. |
| 4 | If there is chipping or peeling paint, it must be removed to create a stable base. However, never dry-scrape on pre-1978 homes. The Safety Rule: Dry scraping releases invisible lead dust. You must mist the peeling area with a spray bottle of water before touching it. The Action: While the paint is damp, use a sharp scraper to gently lift off the loose flakes. Do not force it; if the paint is stuck firmly, leave it alone. Clean Up: Immediately wipe up any paint chips with a damp paper towel and dispose of them in a sealed heavy-duty trash bag. | Start with the loosest section. If lead is detected, it should be encapsulated or removed using the proper methods mentioned in the previous section. |
| 5 | Now that the loose paint is gone, you must roughen the remaining shiny paint so the new primer will stick. Do not use a power sander (unless it has a HEPA vacuum attachment), as this creates the highest volume of toxic dust. The Tool: Use a medium-grit sanding sponge dipped in water. The Action: Squeeze out the excess water so the sponge is damp, not dripping. Scrub the frames and sills in a circular motion. The Result: You should see a “sludge” form rather than dust flying in the air. This sludge traps the lead. Wipe it away frequently with a clean, wet rag. The goal is a dull, matte finish, not bare wood. | It allows better adhesion. |
| 6 | Clean off the surface using a vacuum or a damp cloth to wipe up the area. If lead paint is suspected, use a HEPA vacuum. Standard vacuums aerosolize lead dust, poisoning the air. | |
| 7 | Apply a thin layer of primer and allow it to dry first. If you are restoring bare, desiccated timber using linseed oil, apply your oil-based primer immediately while the pretreatment is still wet (the “wet-on-wet” technique). This forces a deep chemical bond within the wood’s cellular structure rather than just sitting on top. | Once the prep work is completed, you can finally paint the window frames and sills. It includes the primer application. The primer should match the surface you will work on. Use a wood primer for wood frames and sills, a metal primer for aluminum, and a vinyl primer for vinyl ones. You have a bit more leeway when choosing which product to use. You can use different types to work on the material used for the frames and sills. |
| 8 | Once dry, stir the paint you will be using. It’s even if only using a single color. | This ensures that the ingredients are mixed together. |
| 9 | Place painter’s tape or masking tape on the weatherstrips and window tracks to prevent paint from getting into those areas. Do not paint the sash tracks or the parting bead as it causes window sticking, which can break glass and cause lead friction. | Immediately remove any spill that gets to those areas; dried paint will prevent them from working properly. |
| 10 | Dip the brush in the bucket. | Make sure to remove excess by tapping the brush on the sides of the bucket. Apply it on the inside of the frame first, then going down to the jambs. The painting should be done from top to bottom to avoid ruining the finish with drips. |
| 11 | After painting the inside frame of sliding or tilt-out windows, open and close the window a few times to prevent it from getting stuck as it dries. | Do this repeatedly every after an hour or two if the sash was not removed. |
| 12 | If working on sliding windows, paint the upper sash first. | The lower sash should be raised up, while the upper sash should be lowered. Start at the crossbar and work towards the rest of the upper sash. You should also start at the upper sash first of tilt-out windows; access it by tilting down the bottom sash. Allow it to dry first before moving on to the lower sash. |
| 13 | To paint the lower sash, return the upper sash to its original position and drop the lower sash. | Follow the same process as the previous step. |
| 14 | With the windows open, paint the windowsill and casing. It includes the exterior window trim and the edges of the window. For horizontal sills, do not paint with “W” strokes. Apply a heavy “wave” of paint in strictly parallel lines. This allows the self-leveling agents to merge the brush strokes into a glass-like sheet before they dry. Select your coating based on your schedule constraints: choose Sherwin-Williams Emerald Urethane for rapid 4-hour recoat times, or opt for Benjamin Moore Advance if you prioritize a glass-like, self-leveling finish over application speed. | |
| 15 | Once it is dry, add another layer to the sections you previously went over. | Two coats should be applied at a minimum to get the best coverage and to fully protect the surface. Continue applying paint until you get the desired coverage and color. |
| 16 | To protect the surface, you can apply a clear coat that is polyurethane-based as the final step. Do not confuse “dry to the touch” with structural durability. Advanced enamels like Emerald Urethane require a full 14-day cure cycle to chemically harden before they can support heavy static loads (like flower pots) without permanent indentation. | This coating will also act as a sealant to prevent it from being damaged in a short time The surface must be dry before reattaching any fixtures and sashes uninstalled before painting. |
Avoid working in direct sunlight. If working in a humid environment or while raining, add one to two hours of drying time to the manufacturer’s recommendation. This will help ensure any condensation is removed from the air.
