--- title: "Split Tension and Dual Firmness Mattresses" description: "Plain UK guide to split tension and dual firmness mattresses versus zip-and-link — one unit or two, and what to ask." url: "https://bedguide.co.uk/mattresses/split-tension-and-dual-firmness/" category: "mattresses" primary_entity: "split tension mattress" date_published: 2026-08-28 date_modified: 2026-08-28 --- # Split Tension and Dual Firmness Mattresses > A split tension mattress is one mattress with two spring-tension or firmness bands, one for each sleeper. A zip-and-link bed is two mattresses joined with a zip. Shops also say dual firmness or half-and-half. None of these words is a legal standard. Ask whether you are buying one unit or two, and which UK size each half is. ## Key facts - Materials: pocket springs, dual tension spring units, zip-and-link pairs, hybrid stacks - Typical lifespan: 7–10 years Key facts: - Split tension: One unit — Two bands inside one mattress and one cover. - Zip-and-link: Two units — Two mattresses joined. Can mix types and go up stairs apart. - The shop words: Not a law — Dual firmness and half-and-half are catalogue names, not a British Standard. Sources: - [National Bed Federation — regulations and standards](https://www.bedfed.org.uk/resources/regulations-standards/) — UK size names are industry practice, not a legal scorecard. Split-tension labels are shop language on top of those names. Checked 2026-08-28. - [IKEA UK mattress size guide](https://www.ikea.com/gb/en/rooms/bedroom/mattress-size-guide-pub63d34391/) — Reminds you to lock centimetres first. A dual-feel story does not fix a 150 cm mattress on a 160 cm frame. Checked 2026-08-28. ## What is a split tension mattress? A split tension mattress is one mattress with two spring-tension or firmness bands. One sleeper gets one band. The other sleeper gets the other. Shops also say dual firmness or half-and-half. None of those words is a British Standard. The join sits inside one cover. You still buy one UK plan size. A King is 150 × 200 cm. A Super King is 180 × 200 cm. Write those centimetres before you talk about “his and hers”. This page is education. It is not a ranking. Big UK shops sell this idea to couples. We explain the build. We do not pick a brand. ## How is split tension different from zip-and-link? Zip-and-link is two mattresses joined with a zip or a link strip. Each half can be a different type, not only a different tension. Two Singles (90 × 190 cm) often make a Super King width. See [couples and zip-and-link](/mattresses/couples-and-zip-and-link). | Question | Split tension | Zip-and-link | | --- | --- | --- | | How many mattresses? | One | Two | | Can types differ? | Usually no — one stack, two bands | Yes — pocket on one side, foam on the other if sold that way | | Stairs | One large object | Two smaller objects | | Centre feel | A built-in join under one quilt | A zip; a bridge pad can hide it | | Adjustable base | Only if the whole unit flexes | Easier on dual motors | In short: ask “one unit or two?” before you ask “soft and firm”. A side-by-side sits at [split tension vs zip-and-link](/compare/split-tension-vs-zip-and-link). ## Why do UK shops push this for couples? Partners do not share body weight. They do not always share sleep position. Soft, medium and firm labels mix [spring tension and top feel](/mattresses/spring-tension-vs-comfort-feel). A “medium” compromise can leave one person perched and the other bottomed out. Split tension tries to keep one bed and two support bands. It does not fix heat, snoring, or a mattress that is too narrow. A UK Double is still 135 cm wide. Two adults still get about 67.5 cm each. Motion is a separate question. Pocket sprung and foam damp partner movement in different ways. See [motion isolation](/mattresses/motion-isolation). A split unit can still pass bounce across the join. ## What should I ask before I pay? 1. Is this one mattress or two zipped together? 2. Is the split spring tension, top feel, or both? 3. Which UK size is the whole plan, in centimetres? 4. Which tension band is aimed at which body weight? 5. Can I turn it, or only rotate it? 6. Does the warranty treat the join as one product? 7. What base and slat gap does the warranty allow? We do not publish a stone-to-tension chart. John Lewis, Dreams and handmade makers use different bands. Ask the maker which tension they intend for your weight. See [questions to ask in a bed shop](/mattresses/questions-to-ask-in-a-bed-shop). ## Who should skip split tension? Skip it if both of you already like the same support band. A well-chosen single tension is simpler. Skip it if you need two constructions, not two tensions — use zip-and-link. Skip it if the stairs will not take a Super King in one piece. Skip any page that says split tension treats back pain. That is a medical claim. We will not make it. See [support claims](/health/mattress-support-claims). ## Related BedGuide entries - [Couples and zip-and-link](/mattresses/couples-and-zip-and-link) - [Spring tension vs comfort feel](/mattresses/spring-tension-vs-comfort-feel) - [How to try a mattress in a shop](/mattresses/how-to-try-a-mattress-in-a-shop) - [UK standard bed sizes](/sizing/uk-standard-bed-sizes) - [How to choose a mattress](/mattresses/how-to-choose-a-mattress) ## Frequently asked questions ### What is a split tension mattress? It is one mattress with two support or firmness bands, one for each sleeper. Shops also say dual firmness or half-and-half. The join is inside one cover. It is not the same as two mattresses zipped together. ### Is split tension the same as zip-and-link? No. Split tension is usually one mattress. Zip-and-link is two mattresses joined with a zip. Zip-and-link can mix types and is easier on narrow stairs. Split tension looks more like one bed. Ask which build you have. ### Who needs a split tension mattress? Couples whose body weights or liked firmness bands sit far apart, and who still want one cover and one plan size. If you also need two constructions, or you cannot get a Super King up the stairs, look at zip-and-link first. ### What UK size is a split tension mattress? It is still a named UK plan. A King is 150 × 200 cm. A Super King is 180 × 200 cm. Each half is not a full Single unless the ticket says so. Write the whole centimetre pair, then ask how the join is built. --- Source: https://bedguide.co.uk/mattresses/split-tension-and-dual-firmness/ · BedGuide — educational encyclopedia, no affiliate commission. Facts checked against official sources where possible; see https://bedguide.co.uk/editorial-policy. Report an error: https://bedguide.co.uk/corrections.