Best Brushes for Sash Window Painting: 2025 Expert Review
DR Joinery
Expert Joiner & Restoration Specialist
One of the most common questions I get asked is, 'What is the best sash window paint?' Whilst choosing a high-quality, microporous paint is vital for allowing the timber to breathe, the tool you use to apply it is equally important. Even the most expensive heritage paint will look poor if applied with a standard flat brush.
Sash windows are complex mechanisms. You are dealing with narrow glazing bars, meeting rails, and precise cutting-in against the glass. In York's historic properties, where layers of old paint often clog up the movement, achieving a thin, even coat is essential for the window to function correctly.
In this review, I'm looking at the specific brushes that allow you to get the best out of your chosen paint. I've tested a budget option for quick touch-ups, a traditional pure bristle set for oil-based heritage finishes, and a problem-solving set for those awkward corners.
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Specs vs. The Real World
The Spec: "Flat vs Round Brushes"
"A standard 2-inch flat brush covers more area quickly."
On a sash window, a flat brush is a nightmare. You need a round 'sash brush' that can be rotated to cut in sharply against the glass and mouldings without masking tape.
The Spec: "Synthetic vs Pure Bristle"
"Synthetic brushes are always longer-lasting and easier to clean."
For traditional oil-based paints used in heritage work, pure bristle often holds paint better and leaves fewer brush marks, though synthetic is improving for modern water-based systems.
My Top 3 Recommendations
Three options to cover different needs and budgets
Coral 33713 Aspire 21MM Round Sash Paint Brush Professional Firm Pointed Profile
CORAL
This single 21mm brush is an excellent, low-cost options for DIYers tackling a specific window. Ideally sized for standard glazing bars, the pointed profile allows for reasonable accuracy without breaking the bank.
The Good
- Extremely affordable for a specialised tool
- Pointed profile helps with cutting in against glass
- FSC wood handle is comfortable to hold
The Bad
- Single size limits versatility across different window sections
- Synthetic bristles may not hold as much oil paint as natural bristle
Installer Tip:
When painting glazing bars (the thin wood between panes), hold this brush like a pen. Rotate it in your fingers as you move along the moulding to maintain a sharp edge without needing tape.
Priced at £3.37 at the time of writing
Check Price on AmazonProDec 4 piece Trade Professional Pointed Pure Bristle Sash Brush Set
ProDec
For genuine joinery restoration using traditional oil-based paints or varnishes, pure bristle is still king. This ProDec set is what you'll often find in a professional's van. The natural bristles hold more paint and flow beautifully, reducing drag marks.
The Good
- Pure bristle is superior for oil-based gloss and satin
- Full range of sizes ensures you have the right brush for narrow and wide rails
- Copper ferrule prevents rusting (crucial for longevity)
The Bad
- More expensive upfront cost
- Requires more care when cleaning (especially with solvents)
- Can shed bristles initially if not combed out properly
Installer Tip:
Before using these for the final coat, 'break them in' on a primer coat first. This removes any loose bristles that might otherwise end up stuck in your perfect gloss finish.
Priced at £19.50 at the time of writing
Check Price on AmazonCoral 33719 Aspire 5 Piece Round Sash Paint Brush Set with Stubby
CORAL
This set bridges the gap between value and performance, but the real winner here is the inclusion of the 'Stubby' brush. In old York terraces, sash windows often sit deep in the reveal, making it hard to angle a long handle. The stubby brush solves that frustration.
The Good
- Stubby brush is essential for tight reveals and box corners
- Great value at roughly £2.30 per brush
- Micro-tipped filaments leave a smooth finish with modern paints
The Bad
- Synthetic bristles are stiffer, which takes getting used to if you prefer natural bristle
- Handles are basic wood, not varnished/lacquered like premium options
Installer Tip:
Use the 15mm brush for the glazing bars and the stubby 18mm for the meeting rail where space is tight. Don't overload the brush; sash windows need thin coats to prevent them sticking shut.
Priced at £11.48 at the time of writing
Check Price on AmazonFrequently Asked Questions
What is the best paint for sash windows?
Why use a round brush for sash windows?
How do I stop my sash windows sticking after painting?
Do I need to strip old paint off before repainting?
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