# ARDEX X 78 S

Tile adhesive · ARDEX

A 20 kg bag of ARDEX X 78 S covers about 5.5 m², by ARDEX UK's own figure: “Approximately 5.5m 2 at 3mm thick per 20kg bag”. ARDEX UK's other figures are in the table below.
Source: ARDEX UK, ARDEX X 78 S product page, read 12 October 2026.

What it is for, in the maker's words: “ARDEX X 78 S is ideal for fixing fully vitrified or porcelain tiles, and other tiles with low porosity, as well as glass and porcelain mosaics and terrazzo” (ARDEX X 78 S product data sheet, read 12 October 2026).

## The maker's figures

| Figure | The maker's words |
|---|---|
| about 5.5 m² per 20 kg bag | “Approximately 5.5m 2 at 3mm thick per 20kg bag” |
| about 9.4 m² per 20 kg bag | “a 20kg bag of ARDEX X 78 S will cover approximately 9.4m² when using a 5mm x 5mm square toothed and notched trowel” |
| about 1.2 kg a square metre for each mm of bed | “using approximately 1.2kg of powder per m² per mm thickness of adhesive bed” |
- 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.

## Sizes

20 kg bag

## Where to buy it

The page has the shops' own searches for it, and any link there that is paid for is marked Ad: https://buildbatch.co.uk/products/ardex-x-78-s/#where-to-buy. BuildBatch sells nothing and compares no prices.

## Questions

**How much does a 20 kg bag of ARDEX X 78 S cover?** ARDEX UK states about 5.5 m² (“Approximately 5.5m 2 at 3mm thick per 20kg bag”) and about 9.4 m² (“a 20kg bag of ARDEX X 78 S will cover approximately 9.4m² when using a 5mm x 5mm square toothed and notched trowel”), in its ARDEX X 78 S product page, read 12 October 2026. Nothing is added for waste.

**What is ARDEX X 78 S for?** ARDEX UK says: “ARDEX X 78 S is ideal for fixing fully vitrified or porcelain tiles, and other tiles with low porosity, as well as glass and porcelain mosaics and terrazzo” (ARDEX X 78 S product data sheet, read 12 October 2026).

**What sizes does ARDEX X 78 S come in?** The catalogue lists 20 kg bag. A shop may not stock every size.

## Where the figures come from

- ARDEX UK, ARDEX X 78 S product page (https://ardex.co.uk/product/ardex-x-78-s-2/): coverage, read 12 October 2026.
- ARDEX UK, ARDEX X 78 S product data sheet (https://ardex.co.uk/wp-content/uploads/2017/06/technical-datasheet-x-78-s-w-s.pdf): coverage and what it is for, read 12 October 2026.

Written with AI tools; not yet checked by a tradesperson. Follow the bag's own instructions.

The page: https://buildbatch.co.uk/products/ardex-x-78-s/