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Bostik J115 Flexible Smooth Finish Grout

Tile grout · Bostik

Bostik J115 Flexible Smooth Finish Grout takes about 5 m² a kilogram, by Bostik Ltd's own figure: “Approx. 5m² per 1kg mixed grout at 2mm joint width”. Bostik Ltd's other figures are in the table below.

Source: Bostik Ltd, Bostik J115 Flexible Smooth Finish Grout technical data sheet, read 12 October 2026.

Plan wall tiles for a roomPlan floor tiles for a room

Coverage
about 5 m²/kgBostik Ltd's figure
Bag sizes
5 kg1 size in the catalogue
For
Walls and floorsin the maker's words

Where to buy it

The shops' own searches for it. BuildBatch sells nothing and compares no prices.

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Coverage

Bostik Ltd gives 7 figures for Bostik J115 Flexible Smooth Finish Grout, each for the conditions in its own words. Each is the maker's own, with its source below.

Bostik J115 Flexible Smooth Finish Grout: the maker's coverage figures
FigureThe maker's words
about 5 m² a kilogram“Approx. 5m² per 1kg mixed grout at 2mm joint width”Bostik Ltd, Bostik J115 Flexible Smooth Finish Grout technical data sheet, read 12 October 2026
about 0.6 m² a kilogram“Approx. 0.6m² per 1kg mixed grout at 15mm joint width”Bostik Ltd, Bostik J115 Flexible Smooth Finish Grout technical data sheet, read 12 October 2026
0.23 kg a square metre“2mm 300 x 300 x 9mm 0.23kg/m2”Bostik Ltd, Bostik J115 Flexible Smooth Finish Grout technical data sheet, read 12 October 2026
0.57 kg a square metre“5mm 200 x 200 x 6mm 0.57kg/m2”Bostik Ltd, Bostik J115 Flexible Smooth Finish Grout technical data sheet, read 12 October 2026
1 kg a square metre“8mm 300 x 300 x 10mm 1.0kg/m2”Bostik Ltd, Bostik J115 Flexible Smooth Finish Grout technical data sheet, read 12 October 2026
1.62 kg a square metre“15mm 300 x 300 x 9mm 1.62kg/m2”Bostik Ltd, Bostik J115 Flexible Smooth Finish Grout technical data sheet, read 12 October 2026
2.16 kg a square metre“10mm 200 x 100 x 8mm 2.16kg/m2”Bostik Ltd, Bostik J115 Flexible Smooth Finish Grout technical data sheet, read 12 October 2026

What one bag covers at the maker's rate

Arithmetic on the maker's figure: the bag's kilograms divided by a rate a square metre, or times an area a kilogram, with nothing added for waste.

Bostik J115 Flexible Smooth Finish Grout: the area one bag covers at each of the maker's rates
The maker's rateA 5 kg bag
about 5 m²/kg“Approx. 5m² per 1kg mixed grout at 2mm joint width”about 25 m²
about 0.6 m²/kg“Approx. 0.6m² per 1kg mixed grout at 15mm joint width”about 3 m²
0.23 kg/m²“2mm 300 x 300 x 9mm 0.23kg/m2”21.7 m²
0.57 kg/m²“5mm 200 x 200 x 6mm 0.57kg/m2”8.8 m²
1 kg/m²“8mm 300 x 300 x 10mm 1.0kg/m2”5 m²
1.62 kg/m²“15mm 300 x 300 x 9mm 1.62kg/m2”3.1 m²
2.16 kg/m²“10mm 200 x 100 x 8mm 2.16kg/m2”2.3 m²

When the figure runs short

The conditions the maker names
Each figure is for the notch, bed, tile or joint the maker names beside it. An uneven surface, a larger notch or buttering the backs of the tiles takes more.
Waste
None of these figures adds anything for what is left in the bucket or spilt.

What it is for

In the maker's own words.

“Bostik J115 FLEXIBLE SMOOTH FINISH GROUT is a professional quality, cementitious, polymer-modified grout suitable for use on both walls and floors”
Bostik Ltd, Bostik J115 Flexible Smooth Finish Grout technical data sheet. Read on 12 October 2026.

Bag sizes

Questions about Bostik J115 Flexible Smooth Finish Grout

How much does a 5 kg bag of Bostik J115 Flexible Smooth Finish Grout cover?

Bostik Ltd gives a rate a square metre, not an area a bag. At its rates a 5 kg bag covers about 25 m² (“Approx. 5m² per 1kg mixed grout at 2mm joint width”), about 3 m² (“Approx. 0.6m² per 1kg mixed grout at 15mm joint width”), 21.7 m² (“2mm 300 x 300 x 9mm 0.23kg/m2”), 8.8 m² (“5mm 200 x 200 x 6mm 0.57kg/m2”), 5 m² (“8mm 300 x 300 x 10mm 1.0kg/m2”), 3.1 m² (“15mm 300 x 300 x 9mm 1.62kg/m2”) and 2.3 m² (“10mm 200 x 100 x 8mm 2.16kg/m2”): the bag's kilograms divided by the rate, with nothing added for waste.

How much Bostik J115 Flexible Smooth Finish Grout per square metre?

Bostik Ltd states 0.23 kg a square metre (“2mm 300 x 300 x 9mm 0.23kg/m2”), 0.57 kg a square metre (“5mm 200 x 200 x 6mm 0.57kg/m2”), 1 kg a square metre (“8mm 300 x 300 x 10mm 1.0kg/m2”), 1.62 kg a square metre (“15mm 300 x 300 x 9mm 1.62kg/m2”) and 2.16 kg a square metre (“10mm 200 x 100 x 8mm 2.16kg/m2”).

What is Bostik J115 Flexible Smooth Finish Grout for?

Bostik Ltd says: “Bostik J115 FLEXIBLE SMOOTH FINISH GROUT is a professional quality, cementitious, polymer-modified grout suitable for use on both walls and floors” (Bostik J115 Flexible Smooth Finish Grout technical data sheet, read 12 October 2026).

What sizes does Bostik J115 Flexible Smooth Finish Grout come in?

The catalogue lists 5 kg bag. A shop may not stock every size.

Other tile grouts

In alphabetical order, with each maker's own figures. A maker measures its coverage its own way, so the figures are not a test of one product against another. Every product under tile grout.

More from Bostik

The other Bostik products in the catalogue, by name. All Bostik products.

Where the figures come from

This page was written with AI tools from the maker's own documents; it is not yet checked by a tradesperson. The figures are the maker's, and a maker's figure is their best case: follow the bag's own instructions.