Thorndown Stain Blocking Primer


From £19.97

(38 customer reviews)

THORNDOWN™ Stain Blocking Primer. Ideal for use below all wood paints and wood stains. Available in 4x colours.


Courier Instruction (if out) * 


Thorndown™ Paints – FREE Next Day Delivery!*

*Thorndown™ Paint is normally delivered next working day if ordered early enough for us to process and pack, however some remote areas may take a bit longer, and there may be additional charges for some areas. Please see more delivery information here.


THORNDOWN™ Stain Blocking Primer

Thorndown Stain Blocking Primer is a high performing multi-surface primer primarily developed for tannin and stain blocking on timber surfaces. It’s formulated to work on all softwood and hardwood including pressure-treated timber, Accoya, Iroko, plywood, MDF and hardboard. It blocks stubborn and persistent stains including water stains, marker pens, and seals porous surfaces with excellent blocking of bleeding knots and sap streaks. It also contains flash rust inhibitor to stop rust forming and fungicide film preservation to stop paint film degrading with mould. It’s easy to keep your paint job looking great by applying a base coat of stain blocking primer first, stopping tannins from wood coming through and staining your paint coating. For use on any wood, anywhere.

Thorndown Stain Blocking Primer works perfectly with all Thorndown wood paints, there is a choice of stain blocking primer in clear for translucent wood paint colours, UV Clear, and semi-opaque colours, white for whites, off-whites, creams and light colours, grey for all mid to darker tones, and a black.


  • 2x Sizes – 750ml & 2.5L
  • Made in the UK
  • Perfect for softwood and hardwood, including pine, cedar, redwood, plywood, MDF and hardboard
  • Works on all painted surfaces of timber, masonry and plaster
  • Quick drying – dry in 1 hour in fine weather conditions
  • Available in Clear, White, Grey and Black
  • Water-based primer, sealer and stain killer
  • Suitable for use on interior and exterior surfaces
  • Excellent adhesion to all timber and painted surfaces
  • Blocks stubborn and persistent stains including water stains, marker pens and more
  • Seals porous surfaces with excellent blocking of bleeding knots and sap streaks
  • Flash rust inhibitor prevents rust forming while drying
  • Fungicide film preservation stops the paint film degrading with mould
  • Stunning, carefully crafted high performance Eco paint – water-based eco product with minimal VOC (Volatile Organic Compounds) at 0.28%, and low odour


Thorndown Stain Block Primer comes in a choice of Clear (for translucent wood paint colours, UV Clear, and semi-opaque colours), White (for whites, off-whites, creams and light colours), Grey (for all mid to darker tones), and a Black.

Application Guide

What you’ll need: Brush, roller (use a foam roller sleeve) or sprayer; whichever colours you want (or want to mix and match); imagination.

Preparation: For best results, sand surfaces and use a wood preservative if needed on untreated fresh timber.

Application: Use a brush, roller, or HVLP sprayer. ‘Avoid the rain, and apply with the grain’, as they say, and leave to dry. When coating large areas, paint up to still-wet paint, as applying over dry paint can make things look uneven.

Coats: Only 1 coat is needed but you can apply a second on particularly resinous or troublesome wood, like very knotty woods or ones with high tannin bleed or leeching.

Drying: In fine weather, a single coat dries easily in an hour or two (20°C and low humidity), ready to paint on a second coat if required, or to apply a paint top coat.

Cleaning Up: Use hot or cold water, with or without detergent, on paint-wet equipment. Be very careful not to allow sprayer nozzles to dry out – this will make cleaning them almost impossible!

Disposal: Please, please don’t throw away unused or dried paint or preserver into drains or watercourses. Most local authorities have free facilities for disposing of paint and coatings. Tins are fully recyclable but remember to make sure they’re clean.

Coverage: You’ll paint 6m² – 12m² of timber surface (one coat) with one litre; rough sawn surfaces will take a lot more paint than a smooth surface, and second coats take less than the first. So each paint can will do approximately:

  • 750ml up to 4.5m²
  • 2.5L up to 15m²

Storage: Paint will keep for approx. 2 years or more in a sealed tin stored out of freezing or extremely high temperatures. Mix well before use.


Beauty is in the eye of the beholder, and so is colour. We all see and interpret colour slightly differently to each other, as do our VDU screens, software and printers that we use. The colour swatches you see on screen and on a printed colour chart are designed as a guide.

The exact and final colour you paint up at home will look slightly different depending on the material you paint it onto and the lighting. For example a colour painted onto new softwood will look slightly different if painted on old hardwood. If you paint up a wooden planter the colour will look different depending on the lighting and where you put it in the garden.

We always recommend trying a small tin at home, where it’s going to end up. Our colours are made precisely using a technically engineered colour system ensuring continuity of colour throughout batches.


Thorndown™ Paint delivery generally takes 1-3 working days. Postcode areas shown below fall outside the standard UK mainland delivery for our couriers, which will incur additional delivery charges, and will probably take a day or two longer to reach you:

Scottish Highlands (+£9.99)

  • All AB Postcodes, FK19 – 21, IV1 – 20,IV63, IV21 – 24, IV25, IV26 – 28, IV30 – 37, IV40, IV52 – 54, KW1 – 14, PA21 – 35, PA37 – 39, PA36, PA40, PH15 – 26, PH30, PH31,  PH32, PH33 – 41, PH49, PH50

Scottish Offshore (+£14.99)

  • HS1 – 9, IV41 – 51, IV55 – 56, KA27 – 28, KW15 – 17, PA20, PA41 – 49, PA60 – 78, PH42 – 44, ZE1 – 3

Isle of Wight (+£14.99)

  • PO30 – 41

Northern Ireland (+£19.99)

  • All BT Postcodes

Isle of Man (+£29.99)

  • All IM Postcodes

Please Note: There is no delivery service to the Channel Islands or Ireland.

38 reviews for Thorndown Stain Blocking Primer

  1. Ian Skinner

    We ordered this paint after searching for some genuine Antracite Grey colour with RAL 7016 number. We wanted something to exactly match our recently install roller shutter garage door The reason for choosing Thorndowns was the exact colour match and their green ethos in their manufacturing process. The paint arrived the day after ordering which was excellent service The paint itself was a smooth consistency and had very little smell which we expected from its low VOC rating. It brushed on very easily with a nice finish. Touch dry within an hour and 2 coats have given a perfect finish Very pleased. Would consider other products from this company. Ian

  2. Claire Coe

    We would highly recommend Thorndown Wood Paints. The colour is great, it was so easy to apply and dried with a lovely dense coverage.

  3. Mrs. Calcutt

    Love the paint , just glides on and covers really well. Love the colour as well.

  4. Elizabeth Morris

    Hi I ordered the grey paint it was delivered this morning, really impressed with your prompt service

  5. Ian Skinner

    Super service Ordered yesterday arrived today Can’t get better than that Thank you

  6. Linda Duff

    I am so glad I found your product. Initially, I thought it sounded expensive at £15 for a smallish can. Money well spent! It did two coats on my shed and bench. Looks great! I then ordered a sample size for my newish front door which had been damaged by my twin grandchildrens double buggy. I just finished two coats today from a £5 sample pot. No sign of scratches whatsoever. I am ddelighted! Thank you so much.!

  7. Phill

    Excellent service – by yourselves and APC –  as paint arrived at lunchtime today 

  8. Phill

      Thank you for substituting, as requested.  Just need some Sun now – which is in very short supply here this past few weeks 

  9. Mrs. Diane Melody

    I have ordered three different colours from your charts in the last two weeks, and all I can say is that I’m so  pleased with the colours, they are true to the colour charts you sent me. Thank you very much. Keep up the work. Mrs Hills. ps. from ordering to the delivery was fantastic in less than 48 hrs. Just to let you know paint arrived this morning.  Thank you so much for such a wonderful service.  Its a fabulous paint. 

  10. Nicky Hart

    Thank you for the speedy paint delivery My old garage door now matches my new windows perfectly Thank you for a great service x 

  11. Mike Hutchinson

    Super quick delivery and lovely paint to work with. Easy on, good coverage and low smells. At first i thought it definitely looked lighter than the colour on the colour chart card i had, closer to the cathedral green, but i see that in different light that it is indeed closer to sedge as ordered. In any case its a cheery green that goes particularly well with my newly resanded and oiled reddish brown doorstep. Thanks for the quick service 

  12. Shawn Taylor

    We are so pleased with the paint, it covers amazingly well and the colour is fantastic.

  13. Carl Mills

    I just wanted to say that I have just used the paint you sent and found it to be great to use, and has dried quickly with a great look and finish.

  14. Lynsey Gilmour

    We used your paint for the cladding on the dormer on our house earlier this year, and we were so happy with it we’ve ordered it again to repaint all our fences, sheds and the chicken shed to match! It’s wonderful stuff! Thank you! 

  15. Vijay D

    I’ve purchased some of your paint recently and I have to say, it’s incredibly good! Many thanks

  16. Mr. Tom Cleugh

    I have just finished a project of front gates and fencing using your RAL1760 paint and I’m delighted with both the quality of the paint and subsequent end result. Kind Regards

  17. Adrian Hornell

    I’m delighted to tell you that the order I placed 23 hours ago has just arrived (in perfect condition as always)! Regards

  18. Jennifer Owen

    Thank you so much. This is the first time we have used Thorndown paint and it certainly won’t be the last. The colours are great and the coverage is good. There’s no dreadful paint smell, they dry quickly and the brushes are easy to clean. What’s not to like. Packing and delivery were very efficient too.

  19. Alison Wallace

    We loved the paint. Fantastic. We’ve been recommending this to everyone who’s commented.

  20. Andrea Jackman

    I just wanted to drop a line and say thank you for helping me to achieve the right colour for the interior of my greenhouse. The hazel colour of the table in the photo on your website was achieved by mixing it with the Orange you sent and am very pleased with the results now. The jet black on the outside is perfect with the rich colour on the inside. Kind regards

  21. Aniece Khamon

    Wow Caroline, I got an email from APC yesterday and then the paint has been delivered this afternoon. I cant tell you how much I appreciate it. Very impressed and feel very special, thank you so much Very Best wishes

  22. Sarah Sparks

    We’ve just painted the summer house – greymond satin. We are really pleased with the quality of your paint and the colour is lovely. Thank you also for the speedy delivery! Especially during these difficult times. Kind regards

  23. Lee Johnson

    My partner and I absolutely love your paint, the colour is amazing and the coverage, finish and quality is the best we’ve ever used, seriously. We have tried every paint under the sun, but will only be using your brand for everything moving forward. Warm regards,

  24. Pete McClellan

    I got my Anthracite Grey paint yesterday and have been really impressed with it. Cracking stuff; many thanks. Best regards,

  25. Melanie Pursglove

    Thanks for the efficient delivery of the paint. I have used it this weekend on my allotment shed – was concerned in that it has previously been oiled but the product was a dream. Very impressed – performed well off the brush and the colour was exactly what I wanted – coverage and opacity is amazing – a joy to use! The hands on experience has given me great enthusiasm for the product

  26. Rod Whiting

    Have just received from you a 2.5litre can of the above, to paint my Anthracite Composite door surround/Inset between my Kitchen/Garage which was 12mm Hardwood Ply in Beech before your super Paint was applied. I am so pleased with the result; perfect match and finish. Paint Quality was superb and it applies so easily with no brush marks and dries very quickly. I would definitely recommend your company to all my friends etc. Keep up the good work. Many Thanks

  27. Naomi Slade

    I found it really nice to use – it goes on well and spreads evenly, giving good coverage which is not being too thin or thick. And it was also really forgiving when working on wood that is rough or thirsty like parts of my fence. It dries fast which is great when working outside, but not so fast that you have to dilute the bottom of the tin (!). So all in all I got the impression of a quality product, and I approve of the sustainable ethos, too.

  28. Tony Johns

    We used Thorndown paints which were so easy to apply, excellent quality and superb customer service. Given we only live down the road, they even delivered them on their way home. I thoroughly recommend them.

  29. Leigh

    It’s been really fun selecting colours from the Thorndown wood paint range for our nursery development projects. As an eco-conscious business, it’s great to be able to use a range of paints that not only offer high-performance, but they’re also friendly on the environment and an absolute pleasure to use, as well as offering a beautiful variety of colours.

  30. Kim von Coels

    I love your paint! Great coverage. Great colour. Great finish.

  31. Alec

    APC couriers have just delivered the paint before I left for work. First class service, thank you!

  32. Ben Chandler

    One coat was perfect, and great colours

  33. Stuart

    Thorndown Paints are now our preferred Paint Suppliers…. we as a company offer our customers a unique ‘in-house’ painting service for garden sheds and summerhouses. To achieve the quality of finish that is acceptable we now use and recommend Thorndown Paints. The range of colours is extensive from subtle pastel shades to bright vibrant colours. Coverage is superb and the finish on planed timber is second to none, the finished surfaces have a very pleasing semi-gloss texture which gives a highly professional finish on the products painted (Spray or Brush application). We have no hesitation in recommending Thorndown Paint Products.

  34. Annie Legge

    Wow your paint is stunning! I’m not the best at painting and I get bored but I so loved using your paint, it’s really really lovely.

  35. Patrick Finnmore

    Here are a couple of pictures of the window. It’s looking just as good as when it was painted a year ago. If anything I think it’s retained it’s colour/finish a bit better than the Superdeck.

  36. ArtDesignSign

    Gave the workshop a little Christmas cheer with my new Peelable Glass Paint from @thorndownpaints. Absolutely amazing stuff, goes on like a dream and covers really well even with just one coat, will definitely be investing in some more colours for future projects

  37. Janet Carman

    Hi, Just wanted to say thank you so much for the extremely efficient service you provided. My order which you didn’t receive until yesterday afternoon, arrived at 9am this morning.

  38. Terry Strong

    Two coats have really helped reduce the heat and sun glare. Well pleased with the result

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