Everything About Bathroom Tiles: The Buying and Planning Guide

How to Buy the Right Bathroom Tiles First Time

Choosing a tile colour is the enjoyable part. Everything that happens before and after that decision is where most bathroom renovations succeed or fail. Ordering the wrong quantity, picking a wall-only tile for the floor, using rigid adhesive on a timber substrate, or selecting a polished finish for a shower tray are all mistakes that cost hundreds of pounds and days of remedial work. They happen because the practical side of tile buying is rarely explained clearly.

This guide covers everything outside the design decision. How to measure and calculate quantities. How to read tile ratings and grades. What the terminology on the box actually means. Which adhesive goes where. What grout to use in wet areas. How much tiling costs in the UK, and where to source tiles without overpaying.

For help choosing between tile materials (ceramic, porcelain, natural stone, mosaic, vinyl), our bathroom tile types guide covers the physical properties of each. For layout patterns and design styles, see our contemporary tiling styles guide. For what is trending right now in colour and finish, our tile trends article has the latest.

How to Calculate Tile Quantities

Getting the quantity right avoids two equally frustrating outcomes. Too few tiles means a delay while you reorder, and the new batch may not match the original shade exactly. Too many tiles means money sitting in boxes in the garage. The goal is the right amount plus a sensible buffer for cuts, breakage, and future repairs.

Walls

Measure each wall separately: height multiplied by width gives the area in square metres. Add all four walls together. Deduct the area of any windows (measure the opening, not the frame) and the door opening. Add back the internal surfaces of any recessed niches, boxed-in pipework, or shower enclosure reveals, because these need tiling too. If you are tiling above a shower screen to the ceiling, measure the full height.

Floors

Length multiplied by width gives the floor area. Deduct any permanently fixed items you will not tile under (bath panel base, vanity unit base) if applicable. Most tilers tile the entire floor before fitting sanitaryware, so the deduction is often minimal.

Wastage Allowance

Add a percentage to the calculated area to cover cuts, breakage, and pattern alignment. The percentage depends on the layout pattern.

For small areas with large format tiles (a cloakroom tiled in 600x600mm, for example), calculate by tile count rather than percentage. Percentage-based calculations underestimate when the total number of tiles is low.

Always order an additional 5-10% on top of the wastage allowance and store these tiles from the same batch. Even if the range remains available in future, a different production batch will not match your original shade. Once your batch is gone, exact colour matching is impossible.

Understanding Tile Ratings and Grades

Tile packaging carries technical ratings that directly affect whether the tile will perform in your bathroom. Three ratings matter most.

Water Absorption Groups (ISO 10545-3)

This classification determines whether a tile is suitable for wet areas. The lower the absorption, the better the tile resists moisture penetration.

For shower floors, wet rooms, and any surface with constant water exposure, Group BIa (true porcelain, below 0.5% absorption) is the right choice. Group BIb is acceptable for general bathroom walls and floors that do not sit under direct water flow.

PEI Wear Rating

The PEI (Porcelain Enamel Institute) rating measures how well a glazed tile surface resists abrasion. It applies only to glazed tiles. Unglazed through-body porcelain does not receive a PEI rating because there is no glaze layer to wear through.

For bathroom floors, PEI 3 is the minimum. PEI 4 is recommended for family bathrooms where grit, sand, and foot traffic are heavier. Using a PEI 1 or 2 wall tile on a bathroom floor is one of the most common and costly tile buying mistakes.

Slip Resistance

Three testing systems are used in the UK, and suppliers may quote any of them.

The PTV pendulum test is the HSE’s preferred method in the UK. A PTV below 25 means high slip potential. Between 25 and 35 is moderate. Above 36 is classified as low slip potential and suitable for wet bathroom floors.

The critical fact that many homeowners miss is that polished porcelain tiles can show PTV values dropping from 81 when dry to just 15 when wet. Always check the wet PTV value, not the dry one. Matt, textured, and lappato (semi-polished) finishes maintain far better grip when wet. Small-format mosaics with their dense grout network offer inherently good slip resistance, which is why they remain the standard for shower trays and wet room floors.

Tile Terminology Decoded

The terms on tile packaging and supplier websites can be confusing. These are the ones that affect your buying decision.

Rectified vs Non-Rectified

After firing, tiles shrink slightly and unevenly. Rectified tiles have all four edges machine-ground to precise, uniform dimensions with tolerances under 0.5mm. This precision allows tight grout joints of 1.5-2mm, creating a sleek, near-seamless appearance. Non-rectified (or calibrated) tiles retain their post-firing edges with slight size variations of 1-2mm between tiles, requiring wider grout joints of 3-5mm to accommodate the inconsistency.

Rectified tiles cost more because of the additional machining step, but the visual difference on a finished wall is significant. For a contemporary, minimal-grout look, rectified porcelain is essential. For a more traditional or rustic aesthetic, non-rectified tiles with visible grout lines can work in your favour.

Through-Body vs Glazed Porcelain

Through-body (or full-body) porcelain has its colour and pattern running consistently through the entire thickness of the tile. If it chips, the chip is the same colour as the surface, making damage virtually invisible. Glazed porcelain has a decorative glaze layer applied over a different-coloured clay body. Modern inkjet printing allows photo-realistic marble, wood, and stone reproductions on glazed porcelain, but if the tile chips, the contrasting body colour underneath becomes visible.

For high-traffic bathroom floors, through-body porcelain is the more durable long-term choice. For walls and low-impact areas where design variety matters more than chip resistance, glazed porcelain offers a far wider range of finishes.

Surface Finishes

Matt tiles have a non-reflective, textured surface. They offer the best slip resistance when wet, show fewer water marks and limescale spots, and suit bathroom floors. Gloss tiles are highly reflective and make spaces feel larger by bouncing light, but they show every water spot and soap splash, and their slip resistance when wet is poor. Use them on walls only. Satin sits between the two. Lappato (semi-polished) is a partially polished surface with some textured areas remaining, offering a soft sheen with better grip than full gloss. It is a popular compromise for bathroom floors where homeowners want some reflectivity without the slip risk.

Choosing the Right Thickness

Tile thickness affects durability, weight, underfloor heating performance, and what your walls can support.

Weight matters on walls. A 10mm porcelain tile weighs approximately 24kg per square metre. Add 6-7kg for adhesive, and the total load approaches 31kg per square metre. Standard plasterboard supports up to 32kg per square metre, leaving almost no margin. For porcelain wall tiles heavier than 8mm, tile backer board (Wedi, Marmox, HardieBacker) rated up to 40-50kg per square metre is a safer substrate. Sand and cement render handles 50kg or more.

For bathrooms with underfloor heating, thinner tiles (6-10mm) heat up faster and transfer warmth more efficiently. Tiles up to 12mm work well with standard UFH systems. Excessively thick tiles (above 15mm) slow the heat-up response noticeably, though they hold warmth longer once heated.

Adhesive and Grout Selection

The adhesive is the structural bond between your tiles and the substrate. The grout protects the joints. Getting either wrong undermines the entire installation regardless of how expensive the tiles are.

Which Adhesive for Which Substrate

Standard rigid adhesive (C1 or C2 class) works on stable, solid substrates like sand and cement render or concrete. The moment the substrate can move, flex, or expand and contract, rigid adhesive will crack and tiles will debond. Flexible adhesive (S1 deformability class) is essential for timber and plywood substrates, underfloor heating, and large format tiles. Highly flexible S2 adhesive is recommended for the most demanding combinations: large format porcelain on a timber floor with underfloor heating beneath.

Rapid-set adhesive allows grouting within two to three hours rather than the standard 24 hours. Professional tilers use it to keep bathroom refits on schedule. Both standard and rapid versions are available in flexible grades. A 20kg bag covers approximately 4-5 square metres and costs £15-£25 for standard or £25-£48 for premium rapid flex. Leading UK brands include BAL, Mapei, Weber, Ardex, and Norcros.

Cement Grout vs Epoxy Grout

For shower floors, bath surrounds, and wet rooms, epoxy grout is worth the premium. It is completely waterproof, does not harbour mould, and never needs sealing. Cement grout absorbs moisture, stains over time, and develops black mould within two to three years in poorly ventilated wet areas. For walls above the splash zone, polymer-modified cement grout with anti-mould additives is an acceptable budget alternative.

Grout Joint Width

The width of the grout joint depends on the tile type, not personal preference. Rectified porcelain allows tight 1.5-2mm joints. Standard calibrated tiles need 2-3mm. Non-rectified ceramic and natural stone require 3-5mm. Handmade and artisan tiles (Zellige, encaustic) need 3-5mm or wider to accommodate their natural variation. These widths follow BS 5385-1 (wall tiling) and BS 5385-3 (floor tiling) guidance.

What Bathroom Tiling Costs in the UK

The total cost of a tiled bathroom includes far more than the tiles themselves. Adhesive, grout, primer, tanking for wet areas, and labour all add up significantly.

Professional tiling labour in Greater Manchester runs £180 to £250 per day. A skilled tiler covers 10-15 square metres of wall tiles or 8-12 square metres of floor tiles per day, depending on tile size and layout complexity. Herringbone and diagonal patterns reduce daily output by roughly 20-30% compared to standard brick bond.

For a standard bathroom with 15-20 square metres of tiling, the total installed cost ranges from approximately £1,100 for a budget ceramic specification to £2,600 for mid-range porcelain with epoxy grout, and upward of £4,500 for premium natural stone with full tanking. Old tile removal adds £800-£900 if needed. For a detailed breakdown of full bathroom renovation costs including sanitaryware, plumbing, and electrics, see our bathroom cost guide.

Where to Buy Tiles in the UK

High Street

Topps Tiles holds roughly a third of the UK tile market with over 300 stores. Their in-store displays are the largest of any UK retailer, and they offer a free three-sample service. Wickes and B&Q stock budget-to-midrange tiles alongside their kitchen and bathroom fittings, making them convenient for one-stop renovation shopping. Tile Giant (part of the Topps Tiles group) carries ethically sourced ranges and exclusive designs at competitive prices.

Online Specialists

Porcelain Superstore offers up to four free cut samples with no card details required, delivered within three working days. Walls and Floors holds over 20 million tiles in stock with next-day delivery and a price-beat promise (5 stars on Trustpilot from over 44,000 reviews). Tile Mountain carries a large range at competitive pricing with click-and-collect available. Victorian Plumbing stocks tiles alongside adhesives and grout from the BAL range, useful for ordering everything in one delivery.

Premium and Designer

Mandarin Stone operates 16 UK showrooms specialising in marble, limestone, and premium porcelain. Bert and May produces bespoke handmade artisan tiles and encaustic cement tiles (also available through B&Q). Original Style manufactures Victorian geometric tiles and period reproductions in the UK. Fired Earth carries luxury natural stone and artisan ranges.

How to Order Samples

Never commit to a tile based on a screen image. Tile colours look dramatically different in person, and your bathroom’s lighting (both natural and artificial) changes how they appear at different times of day. Order free samples from two or three suppliers, place them on the actual surfaces in your bathroom, and leave them for several days. First impressions fade, and you want a material you still appreciate after the novelty wears off. Check the samples against your chosen sanitaryware, vanity unit, and any paint colours. For guidance on choosing tiles that complement your fixtures, our bathroom tiling service page includes portfolio examples from previous projects.

Ten Mistakes That Waste Time and Money

Ordering exact quantities with no wastage. Every bathroom has more cuts than you expect. Pipes, corners, window reveals, and fixture cutouts all consume tile. Add 10-15% depending on layout pattern, then keep 5-10% extra from the same batch for future repairs.

Ignoring batch numbers. Tile colour varies between production runs. Check the batch code on every box before installation begins. If tiles from different batches must be used, mix them across the room rather than grouping them, so variations blend rather than create visible blocks.

Using wall tiles on floors. A PEI 1 decorative wall tile will crack under foot traffic within months. Always verify that the tile is rated for floor use (PEI 3 minimum) before buying it for a bathroom floor.

Choosing polished porcelain for wet floors. Polished surfaces become dangerously slippery when wet. Check the wet PTV rating, not the dry one. Matt, textured, or lappato finishes are safer for any surface that gets wet.

Using rigid adhesive on timber or heated floors. Thermal expansion and timber flex crack rigid adhesive bonds. Flexible S1 adhesive is the minimum for timber substrates and underfloor heating. S2 is recommended when both are present.

Skipping tanking in wet areas. Tiles and grout are not waterproof. Without a tanking membrane in the shower area, moisture migrates through grout joints to the substrate behind, causing hidden damage that surfaces months later. Our avoiding renovation mistakes guide covers this in detail.

Buying cheap adhesive for expensive tiles. A £10 bag of rigid adhesive under a £90 per square metre porcelain tile on a timber floor is a false economy. The adhesive is the structural foundation. It should match the demands of the substrate and tile, not the tightest line in the budget.

Not accounting for substrate preparation. Floors may need levelling compound (£10-£20 per m²). Walls may need re-rendering or backer board. Shower areas need tanking. These preparatory costs can add 20-40% to the total project cost, but cutting them leads to the failures described in our cheap bathroom fitters guide.

Ordering from multiple sources without batch matching. Topping up an order from a different supplier or at a different time risks receiving a mismatched production batch. Order the complete quantity plus spares from a single supplier in a single transaction.

Choosing tiles before knowing the substrate. The substrate determines the adhesive, the adhesive affects the build-up height, and the build-up height can affect door clearance, threshold heights, and shower tray levels. Know what is behind the walls and under the floor before committing to tile specifications.

Contact us for a free, no-obligation quote on your bathroom tiling project in Greater Manchester. We advise on tile selection, quantities, and specification to ensure the right materials go in the right places.

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