Which Selleys rigid wall filler do you need, and how do you choose?

Selleys makes more than a dozen rigid gap filler formulations. They are all developed to close gaps and cover up holes and cracks in surfaces that are not expected to move or flex, for new builds or maintenance repairs. That qualifier is the whole basis of the category: if the surface moves, you are in the wrong section and should be looking at flexible gap fillers instead.

Within the rigid range, two decisions get you to the right product. The first is how big the defect is — a chip and a large hole are not the same job. The second is whether the surface is exposed to the weather, because the interior and exterior powder fillers are not interchangeable and the exterior one carries a restriction worth knowing before you buy.

What this category covers

Rigid fillers cover simple cracks, chips, holes and dents on interior and exterior surfaces. The range splits into three families: the pre-mixed Spakfilla products, the No More Cracks fillers including two powder fillers, and a mouldable plastic putty for repairs that need shaping rather than spreading.

How to choose

Simple cracks, chips, holes and dents

For everyday defects on interior and exterior surfaces, Selleys directs you to the Spakfilla products. They are pre-mixed and water-based, need only a single application, are fast drying, and can be sanded and painted over once dry.

Pre-mixed and single-application are the two properties doing the work here. A single application means you are not waiting for a first coat to dry so you can build up a second, which is what makes small repairs a same-day job rather than a two-day one.

• Spakfilla Rapid — fast-drying, for quick small repairs, easy to sand.
• Spakfilla Heavy Duty — a strong and durable repair for large gaps and cracks in walls and ceilings.
• Spakfilla Colour Smart — dries white and is easy to sand, which suits repairs that will be painted.
• Spakfilla Wall Repair Kit — wall crack and hole repair with the tools included.

When you need more than Spakfilla: the powder fillers

Selleys positions the No More Cracks powder fillers as the step up. No More Cracks Interior Powder Filler is ideal for use on plaster, plasterboard, bricks and wood that is not exposed to the elements, and gives a smooth, professional finish on walls and ceilings.

Where you need weather and water resistance, use No More Cracks Exterior Powder Filler — but Selleys is explicit that it is for masonry work only. That is a real limitation rather than a preference. It is not the exterior filler for timber, and reaching for it on a weatherboard or a timber frame is using it outside its stated scope.

Filling by the size of the defect

Two of the No More Cracks products are specified by scale rather than by substrate, which is the quickest way to choose when the surface is ordinary interior plasterboard:

• No More Cracks Small Cracks & Dents — for the small defects that spoil a wall or ceiling.
• No More Cracks Large Cracks & Holes — for large cracks and holes in walls, ceilings and other interior and exterior surfaces.

Filling by substrate

Where the surface itself is the deciding factor, the range has products named for it:

• No More Cracks Plaster Filler — for plaster walls and ceilings, dries quickly and sands easily with minimal shrinkage.
• No More Cracks Doors & Trims — for gaps and cracks in door frames and trim.
• No More Cracks Exterior Brick & Render — for gaps and cracks in brick and render, for a smooth finish.

Timber repairs, inside and out

No More Cracks Wood Filler is for repairing furniture, doors and other wood surfaces, and can be painted. No More Cracks Exterior Wood Filler is weather-resistant and easy to sand, which is what makes it the outdoor option.

Choose between these two on exposure rather than on the timber itself. An interior wood filler in an exterior application is being asked to handle moisture cycling and UV it was not formulated for.

When you need to shape the filler rather than spread it

Selleys Plasti-Bond Heavy Duty is a plastic putty that can be moulded before it hardens. Use it where the repair has a form to it — an edge, a corner, a missing piece — rather than a flat void to be filled and sanded back.

The safety divide in this category — the interior and exterior twins are not equivalent

The category page above pairs several products by exposure: an interior wood filler and an exterior one, an interior powder filler and an exterior one. Those pairs look alike, are mixed and applied the same way, and sit next to each other on the shelf. On hazard they are not alike at all, and that is the one place in this range where habit carries across but risk does not.

Group	Products	Classification
Danger	No More Cracks Exterior Powder Filler	H318 causes serious eye damage, H315 skin irritation, H335 may cause respiratory irritation. Contains 10–30% Portland cement
Warning — skin sensitisation	Exterior Wood Filler, Exterior Brick & Render, Large Cracks & Holes, Small Cracks & Dents	H317 may cause an allergic skin reaction
Warning — sensitisation and eye irritation	Plaster Filler, Spakfilla Rapid, Spakfilla Colour Smart, Spakfilla Wall Repair Kit	H317 plus H319 causes serious eye irritation
Not classified as hazardous	Interior Powder Filler, Interior Wood Filler, Doors & Trims, Spakfilla Heavy Duty	No signal word, no hazard statements

The two powder fillers are the sharpest divide on this site. Both are a bag of powder you mix with water. The interior one is not classified as hazardous at all — no signal word, composition given as 100% non-hazardous or below reporting limits. The exterior one contains 10–30% Portland cement and is the only Danger product in the range. Cement is why: wet cement is strongly alkaline, so H318 here is eye damage rather than irritation, and the dry powder gives H335 on the way into the bucket. If you have mixed the interior version bare-handed with no goggles and no mask, that is a habit to break before you open the exterior bag. Goggles while mixing, a P2 mask for the dry powder, and gloves for the wet paste.

The same asymmetry runs through the wood fillers, less dramatically. Interior Wood Filler is unclassified; Exterior Wood Filler carries Warning and H317. The interior product's own sheet still notes isothiazolinone preservatives below the listing threshold and warns that repeated contact may sensitise — so the difference is one of degree, not of kind. Sensitisation is not irritation: it is the immune system learning the material, it is generally permanent once acquired, and it builds from repeated casual contact rather than one bad exposure. Smoothing filler with a bare finger over many small repairs is exactly that pattern.

If the hazard profile is what decides it — a nursery, a household with eczema or an asthmatic, or simply not wanting to glove up for a five-minute repair — four products here carry no classification at all: Interior Powder Filler, Interior Wood Filler, Doors & Trims and Spakfilla Heavy Duty. Between them they cover interior walls, interior timber, door frames and trims, and large interior repairs, which is most of what this category is bought for.

Comparing the fillers on the numbers that decide the job

Two figures settle almost every choice here: how deep you can go in one pass, and how long before you can sand and paint. They are not independent — every product that publishes both gets dramatically slower as soon as you go deep.

Product	Sand / paint time	Depth in one application	Pack
Plaster Filler	30 minutes under 2 mm	See product page	100 g, 220 g tubs
Spakfilla Rapid	30 minutes under 2 mm; 24 hours over 2 mm	See product page	180 g, 260 g tubs
Spakfilla Colour Smart	2 hours at 2 mm	Up to 10 mm in one application	180 g / 400 mL tub
Small Cracks & Dents	1–2 hours at 1 mm; 2–3 hours at 2 mm	See product page	350 g, 750 g, 1.6 kg tubs
Interior Wood Filler	1–2 hours at 1 mm; 2–3 hours at 2 mm	See product page	270 g tub
Doors & Trims	2–3 hours at 2–3 mm	See product page	270 g, 580 g tubs
Exterior Brick & Render	2–3 hours at 2–3 mm	See product page	500 g tub
Spakfilla Heavy Duty	2–3 hours at 2 mm	6 mm layers, each dried before the next	435 g / 385 mL tub
Large Cracks & Holes	2–3 hours under 2 mm; 24 hours up to 6 mm	Up to 6 mm	230 g, 450 g, 1 kg tubs; 230 g tottle
Wall Repair Kit	As Spakfilla Rapid — 30 minutes under 2 mm, 24 hours over	Holes and cracks up to 8 cm wide	Kit with 100 g Spakfilla Rapid

"Rapid" is only rapid while the repair is shallow. Spakfilla Rapid sands and paints in 30 minutes under 2 mm and in 24 hours over it — a forty-eightfold step, not a gradual one. Fill a 3 mm chip with the fast product and you have bought the slowest wait in the table. The same cliff appears on Large Cracks & Holes, at 2–3 hours under 2 mm against 24 hours up to 6 mm. If the defect is deeper than a couple of millimetres, the honest options are to accept the overnight wait, or to build up in layers with Spakfilla Heavy Duty at 6 mm a time.

The exception is worth knowing, because it is the only one. Spakfilla Colour Smart is the single product here that publishes a single-application depth of up to 10 mm, at 2 hours for a 2 mm section — allow longer when it is deeper, cold or humid. For a deep hole that has to be painted the same day, it is the only product in the range whose own specification supports doing it in one pass.

Do not compare these tubs by weight. Two products publish both weight and volume, and they run in opposite directions: Colour Smart is 180 g in 400 mL, Spakfilla Heavy Duty is 435 g in 385 mL. The lighter tub holds the larger volume of filler — roughly 0.45 against 1.13 grams per millilitre. Plaster Filler publishes a density of 0.48, so its 220 g tub is about 460 mL of material, not the small pot the weight suggests. Lightweight fillers are formulated that way to sand easily and shrink little; a dense one is buying you strength in a large repair. Either way, grams on the label are not a measure of how much wall you can fill.

Common questions

What is the difference between a rigid filler and a flexible one?

Rigid fillers are developed for surfaces that are not expected to move or flex — cracks and holes in walls and ceilings. Flexible fillers retain flexibility once cured and go in joints between surfaces that move. See gap filler for those.

Do I need to mix Spakfilla?

No. The Spakfilla products are pre-mixed and water-based, need a single application, dry fast, and can be sanded and painted once dry.

When should I use a powder filler instead of Spakfilla?

Selleys positions the No More Cracks powder fillers as the choice when you need a little more than Spakfilla. Interior powder filler suits plaster, plasterboard, bricks and wood that is not exposed to the elements.

Can I use No More Cracks Exterior Powder Filler on outdoor timber?

No. Selleys states it is for masonry work only. For exterior timber, use No More Cracks Exterior Wood Filler, which is weather-resistant and easy to sand.

Which filler should I use if I am painting over the repair?

Spakfilla Colour Smart dries white and is easy to sand, which is why it is described as suiting painting work. The other Spakfilla products can also be sanded and painted once dry.

What do I use for a large hole in a wall?

Spakfilla Heavy Duty is described for large gaps and cracks in walls and ceilings, and No More Cracks Large Cracks & Holes covers large cracks and holes in interior and exterior surfaces.

Is there an option that comes with the tools?

Yes — the Spakfilla Wall Repair Kit includes the tools needed to repair wall cracks and holes.

What about a crack between the wall and the skirting board?

That is a moving joint, so a rigid filler is the wrong choice. Use a flexible filler from the gap filler range.