Which paint should I use on bare wood?
Which paint should I use on bare wood?
Knotting solution on the knots, a wood primer, then your topcoat — and prime end grain twice.
Bare timber presents three separate problems and each needs its own answer: resin in knots, tannin in the wood itself, and end grain that behaves like a bundle of straws. Knots keep releasing resin for years and will push a brown stain through any number of topcoats unless they are sealed with shellac knotting. Tannin-rich hardwoods bleed a similar stain over the whole surface and need a stain-blocking primer, not just knotting. End grain absorbs many times more paint than face grain, so it needs a second priming coat or it will be the first place moisture gets in — which is why exterior joinery rots at cut ends and mitres before anywhere else.
The options, ranked
| Option | Good at | Bad at |
|---|---|---|
| Shellac knotting solution | Seals resin in knots so it cannot bleed a brown stain through the finish months later. | Only a spot treatment; it is not a primer for the whole surface. |
| Water-based wood primer | Low odour, fast recoat, and flexible enough for exterior joinery movement. | Raises the grain, so the first coat needs cutting back at 180-220. |
| Oil-based primer | Penetrates and seals better on resinous softwood and on very absorbent timber. | Slow, strong-smelling, and yellows under a pale topcoat. |
| Stain-blocking primer | Handles tannin-rich woods such as oak, cedar and mahogany, whose extractives bleed through ordinary primer. | More expensive, and shellac-based versions need methylated spirit to clean up. |
Technique that changes the outcome
- Sand to 120-150, dust off, and wipe with a barely damp cloth
- Knot the knots, then prime everything, then prime the end grain again
- Cut back the raised grain at 180-220 after the first water-based coat
- Prime the back and edges of anything exterior before it is fitted
What goes wrong
- Skipping knotting solution and hoping the primer will cope
- Painting timber that is still wet; measure or wait, because paint over damp wood blisters
- Leaving end grain unsealed, especially on a cut mitre outdoors
Compiled practical guidance rather than a published standard. Product formulations vary by brand and market, so read the label — and where the work is structural, electrical or gas, the regulations that apply where you are govern rather than anything here.
Other paint questions
| For | Use |
|---|---|
| Previously painted wood | Clean it, key it and spot-prime bare areas — and find out first whether the existing paint is oil or water based. |
| Plastic | Any paint, provided an adhesion promoter goes on first — and on polypropylene or polyethylene, the promoter is not optional. |
| Kitchens | A scrubbable acrylic eggshell or satin on the walls — and for cabinets, degrease, prime and use a proper cabinet enamel. |
| Bathrooms | A moisture-resistant acrylic in a satin or eggshell sheen with a mould inhibitor — but ventilation, not paint, is the actual fix. |
| Metal | Remove the rust, apply a rust-inhibiting primer the same day, then an alkyd or a direct-to-metal acrylic. |
| Ceilings | A flat matt emulsion — and if there is a water stain or nicotine, seal it with a shellac-based stain block first. |
| Tiles | Tile paint over an epoxy or adhesion primer on a thoroughly degreased and abraded glaze — and expect a limited life in a shower. |
| Fences | A penetrating stain or fence treatment rather than a film-forming paint — and let new pressure-treated timber weather first. |
| Floors | Two-pack epoxy on concrete after a moisture test and a proper grind; floor-grade varnish or floor paint on timber. |
| Radiators | A radiator enamel — water-based acrylic ones no longer yellow, which ordinary gloss on a hot surface always will. |
| Exterior masonry | A breathable mineral or masonry paint — and on an old solid wall, breathability matters more than any durability claim. |
| Galvanised metal | A mordant wash, a self-etch primer or a purpose-made acrylic primer for galvanising — ordinary oil-based primer peels off in sheets. |
| UPVC | A uPVC-specific paint or an adhesion promoter with an acrylic topcoat — and avoid dark colours, which can distort the frame. |
Common questions
- Which paint should I use on bare wood?
- Knotting solution on the knots, a wood primer, then your topcoat — and prime end grain twice.
- What should I avoid?
- Skipping knotting solution and hoping the primer will cope Painting timber that is still wet; measure or wait, because paint over damp wood blisters Leaving end grain unsealed, especially on a cut mitre outdoors
Related pages
- Which paint goes over previously painted wood? Clean it, key it and spot-prime bare areas — and find out first whether the existing paint is oil or water based.
- Which paint sticks to plastic? Any paint, provided an adhesion promoter goes on first — and on polypropylene or polyethylene, the promoter is not optional.
- Which paint should I use in a kitchen? A scrubbable acrylic eggshell or satin on the walls — and for cabinets, degrease, prime and use a proper cabinet enamel.
- Which paint should I use in a bathroom? A moisture-resistant acrylic in a satin or eggshell sheen with a mould inhibitor — but ventilation, not paint, is the actual fix.
- Which paint should I use on metal? Remove the rust, apply a rust-inhibiting primer the same day, then an alkyd or a direct-to-metal acrylic.
- Which paint should I use on a ceiling? A flat matt emulsion — and if there is a water stain or nicotine, seal it with a shellac-based stain block first.
- Which paint can I use on tiles? Tile paint over an epoxy or adhesion primer on a thoroughly degreased and abraded glaze — and expect a limited life in a shower.
- Which paint should I use on a fence? A penetrating stain or fence treatment rather than a film-forming paint — and let new pressure-treated timber weather first.
- Which paint should I use on a floor? Two-pack epoxy on concrete after a moisture test and a proper grind; floor-grade varnish or floor paint on timber.
- Which paint should I use on radiators? A radiator enamel — water-based acrylic ones no longer yellow, which ordinary gloss on a hot surface always will.
- Which sandpaper grit for bare wood before finishing? Sandpaper grit
Sources
- Typical range compiled from manufacturer specifications — At One Place