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What is decorators caulk :: Posted by: Admin on January 8th, 2013

What is decorators caulk / filler

Decorators caulk is a decorating gap filler, is made of an acrylic and is flexible once dried. It is ideal for areas that have movement but cannot be used like a powder filler and cannot be rubbed down, it can be painted over. It is the best kept decorators secret ever, my wife had never heard about “flexi-filler” as she calls it until I met her.

Notice the spelling also, it is decorators caulk, not cork.

What is decorators caulk used for

Decorators caulk, or decorators filler as it’s sometimes called is used for filling gaps around door and window frames, along the top of skirting boards, gaps around the ceiling and coving line and is ideal for using if there is movement due to it’s flexible properties.

Caulking Gun

Use decorators caulk for:

  • Around Door frames
  • Around Window frames (Wood or UPVC)
  • Skirting boards
  • Ceiling and wall line
  • Around coving
  • Staircases
  • Interior wall corners

How long does decorators caulk take to dry

This is dependent on many factors such as room temperature and humidity, size of gap filled and porousness of where it has been applied. The drying time can be anything from 20 minutes to 2 or more hours. If unsure it is best to leave for a few hours before over painting it.

How to use decorators caulk

Decorators caulk is easy to use, we have written a post detailing how to use decorators caulk on our other blog DIY By Design so there isn’t any need to cover it in depth here.

Why does decorators caulk crack

Decorators caulk may crack if the gap you filled is too large, it may also sink or shrink slightly. If this is the case apply a second layer of caulk over the top of the first one.

If the caulk has cracked or crazed when you have painted it, this could be you didn’t leave it long enough for it to dry.

It isn’t uncommon for paint to crack or craze on top of the filler, this is mostly a problem for emulsions, a simple solution is to paint over the caulk with a non-vinyl paint, such as an acrylic primer.


I have done a review on a caulk that doesn’t crack or craze, I have been using it for a while and the results are good.
Read my Review Of Dunlop Pro Decor Flexible Acrylic Filler Caulk here. And if you would like to buy some for yourself you can buy Dunlop Pro Decor Flexible Filler caulk from here.

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Posted in DIY Tips, Handyman tips | 46 Comments »

46 Responses to “What is decorators caulk”

  1. Little Says:

    I had new windows fitted the fitter filed everything with decorators chalk didn’t matter how big the gap. Is it used on brickwork?

    Date posted : April 17th, 2015 at 8:53 pm
  2. Admin Says:


    It can be used inside and out, if the outside is rendered it is best to use decorators caulk if it is to be overpainted. Are you sure it was decorators caulk and not silicone sealer? This is what most windows fitters use all the time which is a paint if you try and decorate over it.

    Date posted : April 19th, 2015 at 3:20 pm
  3. Wadz Says:

    Hi there

    Your blog is really useful; keep up the good work as its proving helpful to novists like me!

    I’m relatively new to DIY… my decorators caulking has crazed due to my impatience in not allowing sufficient time for it to dry out. I note your comment re acrylic primer, but do I simply apply it over the crazing, or do I prepare beforehand? If some preparing is required, what is actually required?

    Many thanks

    Date posted : October 26th, 2015 at 5:42 am
  4. Admin Says:


    Apply the acrylic primer directly to the caulk.

    Date posted : October 28th, 2015 at 4:05 pm
  5. Marie Says:

    Would one use caulk around a door etc after or before wallpaper?
    Many thanks

    Date posted : March 7th, 2016 at 1:49 pm
  6. Admin Says:


    Use it before wallpapering.

    Date posted : March 7th, 2016 at 2:39 pm
  7. kim Says:

    My daughter has just moved into her flat but all the artex ceilings have cracks running the full length. You can see they have been filled in the past probably with filler. Would caulk provide a better finish before I paint over

    Date posted : March 9th, 2016 at 6:00 pm
  8. Admin Says:


    Caulk will give more than powder filler, but depending on how much the crack moves it may still open up. The only long term solution is to have the joints taped and re-artexed or skimmed with plaster.
    Also, depending on what caulk you buy the emulsion may crack and craze on the caulk. You can prime it before emulsioning over, this should stop it. Or look out for one that says anti crack / craze.

    Date posted : March 12th, 2016 at 4:30 pm
  9. Stuart Thomson Says:


    I have just become aware of this product and wonder if its what i have been looking for. I moved into a new build almost 3 years ago and since then numerous cracks have appeared along the lines of the plasterboard. Can I use this to fill these hairline cracks?


    Date posted : April 22nd, 2016 at 2:09 pm
  10. Admin Says:


    Caulk is a flexible filler, but it cannot be rubbed down due to its rubbery nature when dry. It is fine to use around the ceiling line, skirting, door frames etc but for general crack filling it isn’t suitable. A reday mixed fine filler or a powder filler is better for cracks in walls.

    Date posted : April 22nd, 2016 at 2:59 pm
  11. AnnG Says:

    Thank you for this info. Two follow on Qs:

    Can decorators’ caulk be used in gaps between floor boards? Or is there a better product for this?

    Is it similar or different to the caulking used on boats?

    Date posted : April 30th, 2016 at 1:02 pm
  12. Admin Says:


    Yes, you can use caulk to fill gaps between floorboards. It is flexible so should expand and contract with the movement of the wood.

    I don’t know what would be used on boats.

    Date posted : April 30th, 2016 at 1:40 pm
  13. Alison Says:

    I’ve papered a ceiling with Wallrock thermal liner. There are some small gaps. If I fill them with caulk, then paint the ceiling, will the painted caulk bits look different from the painted paper?

    Date posted : May 18th, 2016 at 6:36 pm
  14. Admin Says:


    Best to use a fine surface filler or a powder filler rather than caulk as caulk can not be rubbed down.

    Date posted : May 21st, 2016 at 2:25 pm
  15. karen Says:

    I stupidly used caulk on walls as filler, I know stupid. Question is paint doesn’t cover it, three coats and still shows through, how can I fix it?

    Date posted : May 24th, 2016 at 10:20 pm
  16. Admin Says:


    The only way really is to coat it, leave it and coat it again. Make sure it is fully dry before applying another coat otherwise it will take of the previous one. Apply as many coats as required. If the caulk has sunk a little, you could apply ordinary filler and then coat it up again.

    Date posted : May 26th, 2016 at 3:17 pm
  17. Nikki Says:

    I have just had a room wallpapered and due to the ceiling be roughly ar texted and the wallpaper not being cut as neatly as it could the edge between paper and ceiling is a bit wonky. Could caulk be used to run along between to make a nice straight finish ?

    Date posted : June 22nd, 2016 at 10:10 am
  18. Admin Says:


    You could but in time the caulk may discolour. You could carefully caulk along paper and paint over it.

    Date posted : June 22nd, 2016 at 2:37 pm
  19. julie Says:

    Is it easy to take out silicone sealant from top of skirting boards, as this as discoloured and I can not paint it… I want to fill it with caulk and paint it.

    Date posted : August 23rd, 2016 at 12:18 pm
  20. Admin Says:


    It is hard to say. Depends on how well the silicone has been put on. But often once you get it started you can pull it out in one length.

    Date posted : August 25th, 2016 at 8:14 am
  21. Anne Says:

    I am proposing to paint walls with a water-based paint (instead of sizing prior to wallpapering – have been told this would be best). However, as with Karen, I have used caulk to fill loads of fine cracks in the plaster walls. It worked very well but is it OK to use a water-base paint (probably thinned down a bit) before wallpapering?


    Date posted : November 26th, 2016 at 5:51 pm
  22. Admin Says:


    You can paint emulsion onto your walls, use a non-vinyl emulsion, it may crack or craze on the filler.

    Sizing the walls maybe a safer long term solution unless you have a reason for painting first. If you paint and then paper if you change paper in the future some of the emulsion may come off that could potentially need filling or show through new paper.

    Date posted : November 27th, 2016 at 2:19 pm
  23. Andrew Says:

    I have new skirting boards that need caulking. Some parts of the skirting boards are fairly flush against the wall, other parts have quite wide gaps. Do I apply the same amount of caulk along all of the skirting board, even where there isnt much of a gap?


    Date posted : November 28th, 2016 at 3:55 pm
  24. Admin Says:


    Just apply the amount of caulk that is required, less on those areas that the skirting is close to the wall and more where there are larger gaps.

    Date posted : November 28th, 2016 at 5:44 pm
  25. Anne Says:

    Hi Adrian

    Many thanks for taking the time to respond to my query. I will take your advice and use size, then paper.
    I was trying to keep my query short so didn’t tell you that I hope to use lining paper and then paint over that with white emulsion paint.
    I guess that sizing will still be the way to go?


    Date posted : December 2nd, 2016 at 11:55 am
  26. Admin Says:


    Yes, Sizing would still be the way to go 🙂

    Date posted : December 2nd, 2016 at 1:44 pm
  27. JakeS Says:

    can I put a layer of filler over caulk or would i need to scrape off the caulk first? thanks

    Date posted : December 13th, 2016 at 12:07 pm
  28. Admin Says:


    I would scrape it off first otherwise when you come to rub down the filler the caulk could flake/roll off also.

    Date posted : December 13th, 2016 at 1:42 pm
  29. Ann Says:

    I’ve had smaller light switch covers fitted and there is now a gap between cover and emulsions lining paper. Can I fill the gap with decorators caulk or any other suggestions?

    Date posted : January 4th, 2017 at 9:37 pm
  30. Admin Says:


    Powder filler maybe a better option as it can be rubbed down, caulk can not be rubbed down.

    Date posted : January 5th, 2017 at 2:40 pm
  31. Chris Says:
    Do you have like a gold or silver acrylic caulk i can use in the corner of 2 walls?

    Date posted : February 10th, 2017 at 11:33 pm
  32. Admin Says:


    Gold or silver colour? No.

    Date posted : February 11th, 2017 at 3:42 pm
  33. Tracey Says:

    I’m repainting old kitchen doors which have an moulding which has cracked after painting previously.
    Would caulk which I then painted over prevent this happening again?

    Date posted : February 22nd, 2017 at 4:14 pm
  34. Admin Says:
    Date posted : February 23rd, 2017 at 11:12 am
  35. Colin Says:

    I want to fill a gap between window plastic trims & the wall. I was hoping not to have to paint this. Will I be ok with caulk or would silicone be best ?

    Date posted : March 20th, 2017 at 1:42 pm
  36. Admin Says:


    You can use either, silicone is ok if you are never going to paint over it, if you are caulk is best. If you only use caulk this in time may discolour as it is meant to be painted over.

    Date posted : March 22nd, 2017 at 2:16 pm
  37. Deb Says:

    I have plasterboarded my porch and have a few gaps. I don’t really want to buy joint filler and was wondering if caulk and/or ordinary filler would be ok to use with scrim and then skimmed.

    Date posted : August 14th, 2017 at 6:16 pm
  38. Admin Says:


    Ordinary filler should be fine with scrim tape. Caulk will not rub down.

    Date posted : August 16th, 2017 at 3:09 pm
  39. Ben Says:

    Hi there.

    Would caulk be the right solution for filling a 12 – 15mm gap between the top of tiles and the ceiling in our bathroom? It’s unlikely to ever get wet but there will obviously steam.


    Date posted : August 23rd, 2017 at 7:22 am
  40. Admin Says:


    It is too big to fill with caulk really, ideally use grout.

    Date posted : August 23rd, 2017 at 3:30 pm
  41. Margaret Says:

    I try to do a bit of DIY myself due to a tight budget.

    I was wondering whether caulk would be a good solution for a creaky staircase?
    The house is old, built in the 1930’s and had some ‘modernisation’ done to it (including the removal of an understands cupboard to make the tiny room look bigger) long before I moved into the house.

    Last summer, I did my best to fill in the underside of individual stair steps that seemed to be creaking the most. I used slithers of wood and wood filler. Then I put some tongue and groove the length of the underside of the stairs. It all seemed to work…until autumn/winter arrived at which point some gaps started opening up in the tongue and groove and the creaking started again. Incidentally, I don’t recall what I used to glue the tongue and groove. Possibly a mish-mash of whatever was available.

    Any advice or information would be greatly appreciated. Thank you in advance.

    Date posted : December 13th, 2017 at 1:58 pm
  42. Admin Says:

    Under the stairs you will see wedge shaped wood normally. These work loose over time and the stairs can creek. If they are banged in tighter and then glued it should solve the problem.

    The other alternative if you don’t have wedges on your stairs is to screw timber under the treads to support them. And fill any gaps.

    Caulk is flexible so will move with the wood so not really a long term solution. Stairs often creek over time due to drying out and moving.

    Caulk would be ok on the tongue and groove though.

    Date posted : December 16th, 2017 at 4:29 pm
  43. Margaret Says:

    That bit should have read understairs cupboard.☺ Predictive text took over. Apologies.

    Date posted : December 13th, 2017 at 2:02 pm
  44. Richard Says:

    Can filler be applied over the top of caulk and will it bond ?

    Date posted : January 15th, 2018 at 8:04 pm
  45. Admin Says:


    Caulk may prevent filler from bonding to it, depending on the brand used. If you need to do this, rough up the surface of the cauld first to give it a key to bond too.

    Date posted : January 16th, 2018 at 4:04 pm
  46. Review of Dunlop Pro Decor Flexible Acrylic Filler caulk :: Property Decorating Says:

    […] I have written about this problem before on this blog, Tips on using decorator’s caulk, also on Rayfields Interiors, How to use decorators caulk and also Fillers – knowing which one to use and on the Improving Your Property blog, What is decorators caulk / filler. […]

    Date posted : August 26th, 2018 at 3:18 pm

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