What a topic cluster actually is
A topic cluster is a deliberate structure: one substantial pillar page covering a subject broadly, surrounded by cluster pages that each answer one specific question in depth, all connected by internal links. The pillar links down to every cluster page; every cluster page links back up to the pillar. To Google, that structure reads as coverage. To a customer, it reads as a business that knows its subject inside out.
Google's systems evaluate expertise at the site level as well as the page level. Ten scattered blog posts on ten unrelated topics build authority in nothing. Ten pages that comprehensively cover one subject your customers care about make your whole domain more credible for every query in that space. That is why well-built cluster sites regularly outrank larger domains on the topics they genuinely own.
Pick pillars from your services, not your keyword tool
The right pillar topics are the services that make you money, phrased the way customers think about them. A keyword tool refines the choice; it should not make it. For each core service, ask: what does someone research in the fortnight before they buy this? Those research questions become your cluster pages, and the service subject becomes your pillar.
For a trades business the candidates are usually obvious: boiler replacement for a heating engineer, loft conversions for a builder, EV charger installation for an electrician. Pick the service with the best margin and genuine search demand, and sanity-check that demand in Google Keyword Planner before committing months of writing to it.
Two or three clusters built properly beat eight started and abandoned. A pillar page needs roughly 1,500 to 2,500 words of genuinely useful coverage, and each cluster needs six to twelve supporting pages published over a few months. Budget your capacity honestly before you commit.
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Worked example: an electrician in the Black Country
Take a concrete scenario: an electrical contractor in Wednesbury who wants more EV charger installation work. The pillar page is 'EV Home Charger Installation: The Complete Guide', a thorough walkthrough of choosing, buying and installing a home chargepoint, ending with a clear enquiry call to action.
The cluster pages
- How much does EV charger installation cost in the UK?
- 7kW vs 22kW home chargers: which do you actually need?
- Tethered vs untethered chargers, explained with photos
- Can you install an EV charger in a rented home or flat? (covering current government chargepoint grants)
- Do you need to notify your DNO before installing a charger?
- How long does installation take? A job diary with pictures
- Solar panels and EV charging: how they work together
- Smart charging rules and regulations for UK homes
Each page answers one question a real buyer asks, uses the electrician's own job photos and pricing experience, and quietly demonstrates the first-hand expertise no AI summary can match. Six months in, the domain has a plausible claim to be the local authority on the subject, and the pillar starts competing for the commercial head terms.
The linking rules that make it work
The structure only exists if the links exist. Apply these rules without exception:
- Every cluster page links to the pillar once, high in the content, with a descriptive anchor such as 'EV charger installation guide', never 'click here'
- The pillar links to every cluster page at the point where that topic naturally arises in the text
- Sibling cluster pages link to each other where relevant: the cost page should link to the 7kW vs 22kW page
- Your commercial service page links to the pillar, and the pillar links back to the service page and contact form
- No cluster page should be reachable only from the blog index; that is an orphan in waiting
Review the links every time you publish. A new cluster page means one new link added to the pillar, and usually one or two added to its siblings.
The planning spreadsheet
Run the whole programme from a single sheet, one row per page, with columns for:
- Page title and the target query
- Role: pillar or cluster, and which pillar it belongs to
- Search intent and the one question the page answers
- Status: planned, drafted, published, refreshed
- URL once live
- Links in and links out, listed explicitly so nothing is forgotten
- Publish date and next review date (refresh cost and regulation pages yearly)
This turns strategy into a checklist. Anyone in the business can see what exists, what is missing and which links are still owed. It also stops the quiet failure mode where pages get written but never connected.
Key Takeaway
Choose one profitable service, build a 1,500 to 2,500 word pillar page covering it end to end, then publish six to twelve cluster pages that each answer one real pre-purchase question. Link every cluster to the pillar with descriptive anchors, link the pillar back to every cluster, and connect siblings. Run it all from one spreadsheet that tracks links owed, and judge success at cluster level in Search Console over three to six months.
Measure by cluster, not by page
Judge the programme at cluster level. In Search Console, filter queries by topic and watch impressions, average position and clicks for the whole cluster over three to six months. Individual pages will wobble; the cluster trend tells you whether Google is beginning to treat you as an authority. Enquiries that mention the content ('I read your guide on chargers') are the signal that matters most.
Also watch behaviour on the site itself: in GA4, check whether visitors move between cluster pages and from cluster pages to the service page. If nobody follows the links, the anchors or their placement need work, because the structure serves users first and crawlers second.
Expect slow starts. Clusters compound: the tenth page benefits from the nine before it in a way the first never could. If you would like help mapping pillars and clusters for your own services, our content team plans and writes these programmes for UK small businesses.