Wall filler buying guide

Wall fillers can be used to even out small imperfections in a range of surfaces. They are made up of binders which harden upon contact with the air and can be lime or plaster-based.

Some common types of filler include fine surface filler, interior filler and multi-purpose filler which is a two-in-one product. These fillers can either come in powder form or as ready-mixed pastes. Here are a few examples of wall filler applications:

• Filling in holes in rented homes.

• Repairing walls or ceilings in order to paint.

• Repairing damage from impacts, scratches or other issues.

In short, there are many situations in which you can use a filler. Wall filler is simply used to cover up superficial blemishes in walls and ceilings.

These products can be used indoors or outdoors. However, please note that unless the product is labelled 'suitable for outdoor use', it is only suited to indoor use. Always check the product specifications before purchase.

Want to fill in a drill hole? Think that old tub of fine surface filler at the bottom of your tool box will do the job? Think again! It is absolutely not recommended to use a fine surface filler for this type of task.

Conversely, you cannot fill very shallow cracks with interior filler. It will simply disappear upon sanding. Multi-purpose fillers can be used to smooth surfaces and fill large and small cracks.

Fine surface fillers

Fine surface fillers are used to cover up imperfections such as hairline cracks and scratches up to a maximum depth of 2 mm.

Interior fillers

Special interior fillers can be used to fill in holes, cracks and other flaws measuring 2 mm to 1cm or even bigger if dealing with drill holes.

Multi-purpose fillers

Multi-purpose or all-purpose fillers can be used for both fine cracks and larger gaps. However, they will offer less coverage than interior fillers designed for bigger cracks.

As mentioned above, fillers are used mainly for walls and ceilings. They are most commonly used to patch up plaster but can occasionally be used for concrete, depending on the formula. Wood, plastic and other materials usually require the use of a specially designed filler.

When it comes to choosing between powder and paste, it should be said that both are good options. However, each type of product is best suited to a specific set of applications.

Powder filler for large-scale renovations

If you have a lot of work to do and a lot of surfaces to prepare – before painting, for example – powder is a good option. Powder wall filler is inexpensive to buy and you will get a lot of filler out of one bag. The downside is that you need to prepare it before use.

This involves mixing the powder with the correct ratio of water as indicated by the manufacturer. Once prepared, the filler needs to be used right away – you cannot save any leftover product. It is therefore important to prepare the right quantity of filler before it dries out so be sure to check curing times.

Ready-mixed filler: a practical option for small jobs

Only got a small surface to fix up? Ready-mixed filler will do the job nicely. This type of product is practical and can be reused. You just need to make sure to close the cap or lid tightly after use. The drawback of ready-mixed filler is that it is more expensive than powder.

Furthermore, this type of product is pre-mixed in precise ratios so it isn't possible to alter the consistency of the filler like you can with powder filler. That said, it can be used to prep or repair almost all types of surfaces.

No matter whether you go for a fine surface filler or an interior filler for larger cracks, you will need the following tools to apply your product:

• A filling knife or wider decorating knife designed for filler; the first features a narrower blade for more precision while the second usually features a wider blade for finishing work.

• Scraper: available in a range of sizes, these versatile tools are great for applying filler; choose the right type of scraper for your task.

• Paint scraper to prepare the surface prior to filling. This type of tool can be used to remove paint bubbles or paint and debris from cracks.

• Sandpaper to sand down the filler and even out the surface once dry.

• A brush or cloth to dust down your surface after sanding and before applying paint.

• Sponge soaked in water to clean up tools after application.

The types of fillers described above are designed for indoor use in dry rooms. As they cure upon contact with the air, they are not suited to areas with humidity. There are, however, special kitchen, bathroom and outdoor fillers.

It's also possible to find fillers with special properties; for example wood fillers and low-VOC fillers. These products often contain resins and additives to make them suitable for specific applications. Here are a few examples:

• Moisture-resistant filler: designed to cope with humid environments.

• Natural fillers: these low-VOC fillers contain natural binders as part of their formulas.

• Masonry repair fillers: designed for outdoor use, these fillers have high mechanical strength and cope well with moisture and the elements.

• Wood fillers: these products are often formulated with wood fibres making them perfect for wood repairs.

It's a good idea to have several small tubs or tubes of ready-mixed filler on hand in your tool box. They won't take up a lot of room, will only cost a few pounds and can come in handy for a range of DIY tasks.