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30 FAQs
How long does exterior filler take to dry?
Drying times vary depending on the product:
• Quick Dry Filler – Ready to paint in just 1 hour
• Exterior Skimcoat, Rock Solid Repair & Tough Multi-Filler – Ready in 24 hours
• Masonry Repair – Allow 48–72 hours for full set.
Always check the product label, as drying times can be affected by temperature and humidity.
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Can I use Fill-Flex with Scrim Tape?
No, scrim tape is not required when using Fill-Flex but can be used to reinforce crack even further.
Whilst not strictly necessary, if you were to use Scrim Tape, you would fill the crack using Fill-Flex, then add the Scrim Tape over the top. Once dry, use a finishing or levelling filler to smooth surface.
Traditional crack repairs often rely on scrim tape to reinforce the joint and prevent future splitting. However, Fill-Flex already contains reinforcing fibres within the formula.
These fibres:
• Improve adhesion
• Bridge small gaps
• Increase flexibility
• Reduce the need for additional reinforcement
Because the fibres are built into the product, they effectively replace the need for scrim in most standard movement-related cracks (such as between skirting boards and walls).This simplifies the repair process and saves time during application.
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Can I use Skim-Flex in my shower?
No, Skim‑Flex is suitable for decorative applications and for use in kitchens and bathrooms, but it is not a waterproofing product like those used in showers.
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Can I use Skim-Flex over Fill-Flex?
Yes. Once Fill-Flex has fully set, Skim-Flex can be applied over the top to smooth and refine the repair, creating a paint ready finish.
Can I sand Skim-Flex
Yes. Skim-Flex is easy to sand once fully dry, allowing you to achieve a smooth, professional finish before decorating.
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What’s the difference between Skim-Flex and Fill-Flex?
For deeper cracks, choose Fill-Flex. For surface levelling, blending, or smoothing over moving surfaces (up to 5mm depth), choose Skim-Flex. Fill-Flex has a depth limit of 10mm (1cm) and is ideal for repairing small, reappearing hairline cracks. It’s fibre-reinforced, remains flexible after it's dry, and is resistant to sanding. This makes it perfect for targeted repairs where cracks are likely to reappear.
Skim-Flex has a maximum application depth of 5mm, so it’s designed as a skim coat rather than a deep filler. It’s best used for surface matching and smoothing over areas that may experience slight movement. It can be applied across wider surfaces to create a uniform finish and can be sanded once dry for a seamless result.
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When can I apply a second coat of Fill-Flex?
You can apply a second coat of Fill-Flex as soon as the first is dry, which usually takes up to 24 hours. The total thickness of the application should not exceed 10 mm (1 cm).
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Can Fill-Flex be used on wood?
Yes, but only on primed wood surfaces.
Fill Flex is suitable for:
Primed skirting boards.
Primed door frames.
Primed architraves.
Other painted or sealed timber trims.
It is not recommended for:
Bare, untreated wood.
Oiled or stained timber.
Surfaces without a primer or paint base.
Structural or load bearing repairs.
Floors.
Unprimed MDF.
Because wood naturally expands and contracts, using a flexible filler between primed timber and walls is ideal for preventing cracks where different materials meet.
If you’re applying filler between skirting and wall, ensure the timber is primed first for proper adhesion and long-lasting results.
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Can I sand Fill Flex?
Due to its flexible nature, Fill-Flex is not easily sanded.
Fill-Flex is reinforced with flexible fibres that allow it to move with the substrate. This flexibility is what prevents cracks from reappearing but it also means the product is resistant to sanding.
Unlike traditional fillers that dry rigid and can be sanded smooth, Fill Flex remains slightly flexible even after drying.
What should I do instead of sanding?
To achieve a smooth finish:
Apply flush to the surface.
Immediately smooth the surface using your finger.
Alternatively, use a slightly damp sponge.
Remove excess product while it is still workable.
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Are Toupret products suitable for use on lime render?
Our Rock Solid Repair Filler and Tough Multi-Filler are suitable for localised repairs on lime render. For individual application specifications, please refer to the product technical data sheet.
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Do I need to spot prime to prevent flashing and grinning if my paint has a high sheen level?
No, you still won't need to spot prime. Just make sure the filler is completely dry before painting.
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Can I skim with exterior filler?
Exterior surfaces
Yes! Our Exterior Skimcoat Filler range comes in powder or ready mixed version. It is designed for smoothing old or damaged render and can also be used to skim over masonry locally.
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Can you apply a finishing filler over Fill Flex?
Problem Surfaces
Yes, it’s a really good idea to finish with either Skim Flex (flexible skim-coat) or Fine Surface Filler. All Toupret products will adhere to Fill Flex once it is fully dried.
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How do I use Exterior Skimcoat Fillers?
Exterior surfaces
We've designed our skimcoat products for smoothing over large areas of masonry and render, allowing for traditional render repairs and eliminating the need to completely strip back old render. It’s designed to be applied thinly (up to 5mm). For deeper filling and repairs, use one of our exterior filling products first. We offer powder or ready to use Exterior Skimcoat products.
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Can interior fillers be used on wood?
Interior surfaces
Our Interior Surface products aren't suitable for wood our but Wood Repair Filler will be perfect. You will be able to paint or stain it in 3 hours.
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Which filler should I use for treating damp walls?
Problem Surfaces
Anti-Damp Render is a treatment filler for damp masonry on interiors or exteriors (such as garages or cellars). It is applied to raw substrates, either in light coats by brush in a criss-cross pattern, or thicker coats with a trowel or a blade to level irregularities in the substrate. However it is applied, a coat thickness of minimum 2 mm is required for the anti-damp properties to be effective. Anti-Damp Render is suitable for raw and non-dripping substrates [refer to the technical datasheet]. It will stand as a barrier against the residual water contained in your substrate while enabling the water vapour evaporation, thanks to its high water vapour permeability. Please ensure that the paint covering is also water vapour permeable.
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What is the maximum depth for Anti-Damp-Render?
Problem Surfaces
Anti-Damp Render performs best when applied to a depth of up to 1cm on damp substrates. Any deeper, and the breathable barrier created by the filler may be compromised, blocking the water flow to such an extent that it may force its way through the filler, causing it to peel off.
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Can I apply exterior filler onto damp walls?
Exterior surfaces
Masonry Repair Filler is very good for deep masonry repairs, can be shaped, and can be applied to damp masonry. You can use it to fill big defects in the substrate and you can also skim with it. It's paintable after 48 to 72 hours.
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Is Anti-Damp Render a filler or a render?
Problem Surfaces
It’s a filler with high cement content that does a rendering job on masonry substrates. The added ingredients provide anti-damp properties that allow it to act as a barrier to water penetration while still letting the substrate breathe. Anti-Damp Render is best applied to damp substrates to a depth of up to 1cm. Any deeper, and the breathable barrier created by the filler may be compromised.
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What is the difference between Joint & Skim: Ready To Use and Renovation Skimcoat?
Joint, Skim & Fill
The Joint & Skim product is very fine and is designed mainly for taping and jointing and fine skimming on plasterboard. The Renovation Skimcoat is also fine, but thicker, and is especially good for levelling surfaces and thicker applications, such as covering textures (but can also happily be used for taping and jointing).
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Rock Solid Repair Filler vs. Masonry Repair Filler: Which should I use?
Exterior surfaces
For bare masonry (damp or dry) apply Masonry Repair Filler. For all other dry substrates, including glass and glazed tiles, use Rock Solid Repair Filler.
Due to the strong properties of Rock Solid Repair Filler, it will need to be shaped and sanded before it sets. Masonry Repair Filler, on the other hand, can be sanded with ease.
If you’re looking to paint over the filler, consider that Masonry Repair Filler is cement-based and therefore requires pH levels to drop back before you are able to do so. This will take between 48 and 72 hours. Rock Solid Repair Filler can be painted over in 24 hours, regardless of the depth to which it has been applied.
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Can I buy direct from Toupret?
Where to Buy?
Unfortunately, we don’t sell direct, but you can find your nearest distributer on the Store Locator. Or if you’d like to contact us we can ask your local Toupret sales/technical representative to get in touch.
Can you send me a sample?
Where to Buy?
Unfortunately, we can’t offer free samples, but if you would like your local sales rep to contact you for some product advice or to direct you to a local stockist, please contact us.
Which filler should I use for levelling the surface of an exterior wall made of various materials and locally covered with paint?
First of all, make sure that the paint on the base substrate is not a plastic-based coating. This can’t be covered by any filler and needs to be stripped beforehand. Then, after scraping away non-cohesive areas and checking the moisture rate of your substrate, you can apply Rock Solid Repair Filler or Tough Multi-Filler to fill holes, cracks and various gaps. Once your localised filling is dry, you can apply our Exterior Skimcoat or Tough Mukti-Filler as a skim coat (up to 5mm) to achieve a really smooth and even wall. Then, once these filler coats are dry, you can apply your final coat.
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Can Joint, Skim & Fill cover Artex® and have a long-lasting, hard finish?
Joint, Skim & Fill
Yes, our Joint, Skim & Fill ready mixed and powder products will both do the job depending on the depth of the Artex. If it’s been de-nibbed, either would be fine and will be just as hard as plaster, dry wall and other fillers.
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What’s the difference between Joint Skim & Fill: Quick Dry and and Patch & Repair Filler: Quick Dry?
Joint, Skim & Fill
There are a couple of important differences between these products, which are designed to complement each other. Joint, Skim & Fill is designed for doing large areas of jointing and skimming, Patch & Repair Filler is for smaller holes and cracks. The adhesion on Joint, Skim & Fill powder conforms to European Standard EN 13963 which concerns reaction to fire and flexural strength for jointing products. For this reason, we proudly bear the CE logo on the jointing products in the range. This is the standard that’s required for commercial jointing, so you can be sure the product will stand up to the job. Patch & Repair powder is a bit harder than Joint, Skim & Fill powder when dry. Because Joint, Skim & Fill is primarily designed for smoothing over larger surface areas, the formula helps to make the job of sanding over large areas easier and more comfortable! But sanding is still easy when using Patch & Repair to fill smaller holes and cracks.
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Do your fillers still allow the walls to breathe if a large area is covered?
Exterior surfaces
Interior surfaces
Joint, Skim & Fill
Yes, they do! Our fillers are moisture vapour-permeable so your wall will be able to breathe, even if a large area is covered. Just make sure you also apply a breathable paint.
Do your fillers set chemically or atmospherically?
Our powder fillers set chemically and then dry atmospherically. In fact, all powder fillers containing plaster or cement work this way. The plaster or cement reacts with the water first to set to a solid crystal lattice. That structure is then fixed while the water evaporates until it becomes fully dry. Our ready-mixed fillers dry atmospherically - they lose moisture through the substrate and in the air. This is because there is no chemical reaction in this formula. Again, this is the case for most ready-mixed fillers.
Can I mix filler with paint or tint?
We advise against putting any additives into our products because this may affect the performance or the chemical composition.
How does this compare to plaster?
We love questions like this! We’re finding that more and more decorators, drywall specialists and builders are choosing to use fillers (such as our Joint, Skim & Fill range, for example!) as an alternative to plastering for some jobs. Not only do skimming fillers give a durable finish, but they’re breathable, don’t need to be sealed before decorating and dry white. They’re also very convenient to work with, being really easy to spread and with an open time of 45 minutes (rather than about 15 with plaster) yet they are dry in hours, rather than days, and are easy to sand for a perfect finish. Better and faster – win win!
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