Gloss Paint: Water-Based vs Oil, Satinwood vs Gloss, and How to Get a Pro Finish on Woodwork

Buy a tin of oil-based white gloss for your new skirting boards in 2026 and you'll be repainting it in three years because it'll have gone the colour of weak tea. The reformulation that happened around 2010, when European VOC limits killed the old solvent-heavy recipes, made modern oil gloss noticeably worse at staying white than the stuff your dad used in the 1990s. The professional decorators worked this out a decade ago and shifted to water-based satinwood. Most homeowners haven't had the memo yet, and the result is a generation of new-build skirting that's slowly turning yellow under the stairs.

This page covers what trim paint to buy for the woodwork in a new extension, why the water-based vs oil-based decision matters more than the brand, and the application technique that beginners with a brush get systematically wrong.

What it is and what it's for

Gloss paint is the umbrella term for the high-pigment, hard-wearing paint applied to internal woodwork: skirting boards, architrave (the moulding around door frames), door leaves, door linings, window boards and any timber detailing. Strictly speaking, "gloss" is the highest sheen level, but in UK retail the word is often used loosely for any trim paint regardless of finish. The technically correct term for the whole category is "trim paint" or "wood paint", and within it you have three sheen levels:

• Gloss, around 80% sheen. Mirror-like, traditional, durable.
• Satinwood, around 30 to 40% sheen. The current UK default for new woodwork.
• Eggshell (water-based), around 15 to 20% sheen. Subtle, low-glare.

There are two formulation families: oil-based (solvent-borne) and water-based (water-borne). UK regulations cap the solvent content of trim paints sold in Great Britain. Under the Volatile Organic Compounds in Paints, Varnishes and Vehicle Refinishing Products Regulations 2012 (SI 2012/1715), interior trim paints are limited to 130 g/L for water-borne formulations and 300 g/L for solvent-borne. These are the Phase II limits that came into force in 2010 and which forced manufacturers to reformulate their old high-VOC oil glosses. The reformulation is the reason modern oil gloss yellows faster than the products on the shelves twenty years ago.

There is one British Standard worth knowing about: BS 6150:2019, the "Painting of Buildings Code of Practice". It's the document that sets out preparation, application and finishing requirements for painted woodwork and is what your decorator will reference if there's a dispute about workmanship.

The water-based vs oil-based decision

This is the single most important call you'll make on extension woodwork, and the trade has already made it. Walk into a busy decorating merchant and ask three professional decorators which they're using on white skirting and you'll get three answers that all sound like "water-based, obviously, because oil-based goes yellow."

Here's the comparison in detail.

For a new extension where the woodwork will be white or off-white, water-based satinwood is the right choice. Full stop. The yellowing problem on oil-based whites is severe, well-documented across forums and trade testing, and not solvable with brand selection. It's a chemistry problem in the resin family, not a quality issue with one product. Even Dulux's own product page for solvent-based satinwood includes a manufacturer's note recommending water-based alternatives if long-term whiteness matters.

Where oil-based still has a case: for dark or strong colours where yellowing is invisible, in unheated outbuildings where minimum application temperature matters, or for traditional period properties where the deeper flow and gloss of oil-based is the desired aesthetic. For everywhere else, water-based wins.

Sheen levels: which one to use

For most extension woodwork, you have three serious options.

Satinwood is the modern default. Around 30 to 40% sheen, slightly forgiving of imperfections in the underlying timber, washable, and the finish that contemporary kitchen and living spaces are usually photographed with. Skirting, architrave, door frames and most door leaves all look right in satinwood. If you can't decide, choose satinwood.

Eggshell (water-based trim eggshell, not emulsion eggshell) is even lower sheen, around 15 to 20%. Useful where you want the woodwork to recede visually rather than draw the eye. Looks particularly good on tall skirting in older properties or on panelled walls. Note that water-based trim eggshell and water-based emulsion eggshell are completely different products despite the shared name. Trim eggshell is for woodwork; emulsion eggshell is for walls. Don't substitute one for the other.

Gloss (around 80% sheen) is the traditional choice and still has its place. Maximum durability for high-traffic woodwork (doors that get scuffed by toddlers, hallway skirting, stair rails). The downside is that high gloss is brutally honest about the timber underneath. Every dent, every nail-hole, every uneven sand mark gets highlighted by the reflection. You need flawless preparation to make gloss look right. Satinwood forgives, gloss judges.

A common new-build extension scheme: water-based satinwood on skirting, architrave and door frames; same product or matched gloss on the door leaves themselves. Some homeowners like the slight contrast of higher-sheen doors against satin trim. That's an aesthetic call.

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Trade paint vs retail paint

There is a real, measurable difference between Dulux Trade Quick Dry Satinwood and Dulux retail Quick Dry Satinwood, and any decorator who's used both will tell you which is which inside ten minutes of opening the tin. Trade paint contains higher pigment density, more titanium dioxide for opacity, better thickeners that hold the paint on the brush without dripping, and a higher resin content that makes the dried film tougher.

According to Dulux's own technical materials, trade formulations can be thinned by up to 30% while still maintaining opacity, and coverage is 30 to 40% greater than the retail equivalent. In practical terms this means trade paint covers in two coats where retail might need three, and the dried finish is harder to scratch.

The price gap is small. Dulux Trade Quick Dry Satinwood 2.5L runs £43 – £52; the retail Dulux Quick-Dry Satinwood 2.5L sits around half that. You're saving a small amount by buying retail and adding an extra coat to every length of skirting. The maths doesn't work.

Where to buy trade paint without a trade account: Screwfix, Toolstation, Brewers and the Decorator Centre all sell to the public. You don't need a card. Wickes sells some Dulux Trade ranges in-store too.

Preparation and the paint system

Skipping prep is what causes paint to peel within 18 months. There is no paint, no matter how expensive or well-reviewed, that will stick to a poorly prepared surface for long. The system below is what works for new bare softwood or MDF in a new extension, and it's what professional decorators do when they're being paid by results rather than by the hour.

The standard system for new bare timber

1. Knotting solution on every visible knot (softwood only). Pine resin under heat and humidity bleeds through paint as a yellow-brown stain that becomes visible weeks or months after painting. The fix is to seal each knot before any primer goes on. Use shellac-based knotting solution applied with a small brush at under £5. Note: traditional shellac knotting can react with some water-based primers applied directly over it. For softwood that's going under a water-based system, the safer choice is Zinsser BIN, a shellac-based stain blocker formulated to be compatible with modern water-based topcoats.

2. Primer/undercoat. Bare timber and MDF both need a primer. For softwood, an acrylic primer-undercoat is fine if you've sealed the knots with BIN. For MDF, the cut edges are extremely porous and can swell when wet, so a shellac-based or oil-based MDF primer on the cut edges (corners, mitre cuts, scribed ends) is best practice before a water-based system over the top. Skipping primer is the single most common cause of paint peeling on new woodwork.

3. Two topcoats of trim paint. Sand lightly between coats with 240 or 320 grit sandpaper to remove dust nibs and create a key for the second coat. Wipe with a tack cloth before recoating.

If you're using a self-undercoating gloss (most modern oil-based glosses are sold this way) you can skip the dedicated undercoat and apply two topcoats directly over knotting and primer. Read the tin.

The compatibility trap when repainting existing woodwork

Switching paint families on existing woodwork is where most homeowner failures happen. The two compatibility rules:

• Water-based over oil-based: the new paint will not bond to the slick, cured oil surface unless you create a key. Sand the existing paint with 120 to 240 grit until the sheen is gone uniformly, then wash with sugar soap to remove dust and grease. An acrylic adhesion primer (Zinsser Bullseye 1-2-3 or BIN Aqua) bridges from cured oil to fresh water-based.
• Oil-based over water-based: the new oil paint will trap residual moisture and solvent in the water-based film below, and when the oil topcoat skins over before the water below has fully cured, the result is cracking. If switching back to oil, allow the water-based to fully cure (a week minimum, longer in cold or damp conditions) and then sand for adhesion before applying the oil topcoat.

When in doubt: sand to remove sheen, sugar-soap wash, and bridge with an adhesion primer. Skipping any of these is the difference between paint that lasts a decade and paint that scratches off with a fingernail in eighteen months.

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Application technique: the slap-it-on rule

This section is where homeowner decorating goes wrong most often, and the single most important practical difference between water-based and oil-based paint that nobody explains in the retail aisle.

Oil-based paint flows. You can brush a coat on, then come back five minutes later and gently work the brush over the wet film to smooth out marks and even up the coverage. The paint is forgiving because it stays open (wet and workable) for fifteen or twenty minutes.

Water-based paint does not flow like that. It stays open for two or three minutes at most, and during that window you can manipulate it. After that, the surface starts to skin even though the paint underneath is still wet. Once the surface has skinned, going back over it with a brush drags the half-set film, leaves visible brush marks, and creates a stippled or "balled" texture that you cannot smooth out without sanding back.

The trade rule, repeated on every decorator forum, is some variant of "lash it on, lay it off, leave it alone" or the more memorable "slap it on Bob Ross style, never go back". The technique:

1. Load the brush generously. Water-based paint needs more paint on the brush than oil-based, not less. A starved brush gives you brush marks straight away.
2. Apply in long, decisive strokes following the grain. Don't dab.
3. Lay off (a single light pass with the brush tip following the original stroke direction) within 30 seconds of laying down the paint.
4. Walk away. Do not come back to "fix" anything you can see. Whatever you see now will look fine when it's dry. Whatever you create by going back will be permanently visible.

If you have brush marks anxiety and a perfectionist instinct, you will have to consciously override it for water-based work. One DIY forum thread describes a homeowner who threw away four skirting board lengths learning this lesson before it stuck. The technique reads as counter-intuitive ("just leave the marks?") but it is correct.

Brush, roller or spray

For most homeowners on a typical extension, the practical answer is a combination of brush and small foam roller.

• Brush for cutting in: the join between woodwork and walls, internal corners, and any beaded or moulded detail. A 50mm angled-sash synthetic brush is the right tool for water-based work, because natural bristle holds too much water and bloats. Spend £6 minimum on a decent brush; cheaper brushes shed bristles into the paint. The Hamilton For The Decorator range, Harris Seriously Good, and the budget Purdy XL are all fine.
• Small foam roller (4 inch) for the flat sections of skirting and door leaves. The foam roller leaves a finer, more even film than a brush, with no brush marks. The orange peel texture from a foam roller is barely visible at a normal viewing distance and disappears entirely on satinwood and eggshell finishes (it's slightly visible on full gloss).
• Brush then immediately roll is the technique for the best amateur finish: apply paint with the brush in 1m sections, then run the foam roller over the wet brushed area to flatten the brush marks. Treat brush and roller as one combined tool, not two separate steps.

Spray application (HVLP for the best finish, airless for speed) is what kitchen joinery factories and full-time spraying decorators use, and it produces a finish a brush cannot match. It also requires several hundred pounds of equipment, masking up the entire room with plastic sheeting, and a steep learning curve. Not recommended for a one-off extension. For homeowners who want a sprayed finish, the practical answer is to buy pre-finished doors and skirting from a joinery shop that includes spraying in the price.

Drying conditions

Water-based paint is sensitive to temperature and humidity. The minimum application temperature is 8°C for most products. Below that, the paint film won't form properly and the resin won't fuse, leaving a porous, weak coating. In an unheated extension in winter, run a temporary heater for 24 hours before painting and keep it on through the drying period.

In hot, sunny conditions, water-based paint dries on the brush before you can lay it off. The trade tips: wipe the surface with a damp cloth before painting to slow drying, work in shade rather than direct sun, dip the brush in a water bucket periodically to keep it loaded, and on really hot days add a paint conditioner like Owatrol Floetrol or Smith and Rodger Flow and Bond to extend the open time. Note that Floetrol slightly reduces sheen, so use sparingly on full-gloss work.

How much do you need

Trim paint coverage runs 12 to 16 m² per litre per coat in practice, with manufacturer figures of 17 to 20 m²/L being theoretical maximums on smooth prepped surfaces. Use 14 m²/L as a planning figure for woodwork and 10 m²/L if any of the surfaces are textured or porous (bare softwood, sanded MDF edges).

For a typical single-storey extension with one new room plus utility, you'll have roughly:

• Skirting: 25 to 30 linear metres at around 0.15 m² per linear metre = 4 m²
• Architrave around 3 internal doors: 9 m total at 0.07 m² per linear metre = 0.6 m²
• 3 internal door leaves and frames: 3 doors x 4 m² each (both faces and edges) = 12 m²
• 2 window boards: 1 m² total

Total surface area: roughly 18 m². Two coats: 36 m². At 14 m²/L coverage, that's 2.6 litres of finished topcoat. Plus primer for the same surface area: another 2.6 litres. Plus knotting solution: one small tin covers an entire extension's worth of softwood knots.

Round up to one 2.5L tin of primer plus one 2.5L tin of topcoat, with a second 2.5L tin of topcoat held back for the third coat where coverage is patchy (typically architrave and door reveals where the brush has to work into corners). Total trim paint cost for a typical extension: £120 – £200.

Cost and where to buy

Trim paint pricing varies by brand tier and by formulation. Water-based trade products generally cost more per tin than oil-based equivalents, because the formulation is harder and uses more expensive resins. The trade-off is that they last longer in service, which is what matters.

Premium water-based eggshell sits at the top of the price range. Dulux Trade Diamond Eggshell water-based runs £52 – £58 for 2.5L. Pay it once for visible woodwork in a feature room and you'll get a finish that doesn't need redoing for a decade.

The shellac-based primer for sealing knots and MDF edges (Zinsser BIN) costs £22 – £28 for a 1L tin. One tin is enough for an entire extension's woodwork prep.

Where to buy

• Screwfix and Toolstation for Dulux Trade, Johnstone's Trade, Crown Trade, Leyland Trade and Zinsser. Click and collect, no trade card needed. Prices typically 10 to 20% below B&Q for identical product.
• Brewers decorating merchants for the widest range of trade brands, including Tikkurila, Bedec and the harder-to-find product lines. Knowledgeable counter staff who actually use the paint they sell. Open to the public; trade discount available on application.
• Wickes stocks some Dulux Trade ranges and a respectable own-brand quick-dry satin. Convenient for last-minute additions but rarely the cheapest.
• B&Q stocks retail Dulux, Crown and Sandtex. The retail products are usually adequate but not what professionals choose. Often discounted in spring sales.
• Specialist online (The Paint Shed, Decorating Direct) for trade-grade products across all brands at the keenest prices. Good for ordering ahead before the work starts.

Sequencing with the rest of the build

Two practical timing decisions decide whether the trim paint actually survives the rest of the project.

Paint before the carpet goes down. The full cure time for water-based satinwood is around a week, and for oil-based products it's four to six weeks. Until full cure, the paint film is soft and easily scratched. Carpet fitters dragging rolls of carpet across freshly painted skirting will leave permanent marks. Tile-cutting on the floor, plumbers running pipework or kitchen fitters lifting cabinets all do the same. Schedule the painting of skirting and architrave to be one of the last things before flooring goes in, with at least seven days of undisturbed cure time before any other trade comes through.

Caulk before topcoats, never after. The bead of decorator's caulk that fills the gap between skirting and wall must go on between the primer and the first topcoat, not after the topcoats are dry. Caulking over a finished surface leaves visible smear marks because the caulk sits proud and the top of the bead never matches the surrounding paint texture. The correct sequence: prime, fix the boards, caulk all gaps, then topcoat over the caulk to lock it in.

Common mistakes

Buying retail Dulux when Screwfix sells Dulux Trade for similar money. The price gap between retail and trade is small. The performance gap is meaningful. Always check the trade tin first.

Painting bare softwood without sealing the knots. Pine resin will bleed through any number of topcoats applied over an unsealed knot, and the only fix is to strip back to bare timber, seal the knot properly with shellac, and repaint. Knotting solution costs under £5 and takes ten minutes. Skipping it costs a day's repaint.

Using oil-based gloss on white skirting in 2026. It will yellow. You will be repainting it in three years. There is no oil-based reformulation on the market that has solved this problem. Use water-based satinwood instead.

Going back over water-based paint to "fix" brush marks. This is what creates the worst brush marks. Lay it down, lay off in one direction, walk away. The marks you see at the brush stage almost always disappear during drying. The marks you create by going back over half-dried paint never disappear.

Painting MDF cut edges with water-based paint without sealing them. The edges swell, fur up and stay that way permanently. Buy pre-primed MDF and seal the cut ends with shellac primer before fitting.

Skipping the primer when switching from oil to water-based on existing skirting. The new paint will appear to bond and then peel off in sheets six months later. Sand the existing oil paint with 240 grit, sugar-soap wash, and use an acrylic adhesion primer (Zinsser Bullseye 1-2-3 or BIN Aqua) before the new water-based topcoats.

Painting in a cold extension. Below 8°C, water-based paint won't form a proper film. Run temporary heating for 24 hours before painting and keep it on through the recoat window. Painting an unheated room in November and assuming it'll be fine is a recipe for soft, weak paint that scratches off the first time anything brushes against it.

Where you'll need this

• Decoration - trim paint goes on skirting, architrave, door frames, door leaves and window boards as part of the standard decoration sequence after the walls have been emulsioned

These materials appear across any extension or renovation project that involves new internal woodwork. The product selection and application technique above apply regardless of project type.