Spanish Stair & Barrier Rules: Riser, Going, Handrails, Guarding

The requirement

A house stair in Spain is built to DB-SUA 1, §4.1. Riser (contrahuella): 20 cm max. Going (huella): 22 cm min. Clear width: 0.80 m min. Handrail: 90–110 cm. Guards: 0.90 m, or 1.10 m past a 6 m drop. There is no 2C+H check for a home’s own stair.

DB-SUA is the CTE’s book on safe use and access. First, get the class right. The CTE glossary (Anejo A) puts the stair inside a single-family or attached home in the class uso restringido. That means restricted use. Shared and public stairs sit in “uso general” instead. That class has stricter rules, and one extra rule. This page covers the house class.

• Riser (contrahuella): how tall each step is.
• Going (huella): how deep each step is, measured in the direction of travel.

For this class, each riser can be 20 cm tall at most. Each going must be at least 22 cm (DB-SUA 1, §4.1). Keep every step in a flight the same. The same clause sets a clear width of at least 0.80 m per flight (§4.1, point 1).

Curved stair? Under 1 m wide, measure the going on the stair’s own axis. At 1 m or wider, measure 50 cm in from the narrow side. Even then, the going must not drop under 5 cm at the narrow end. And it must not pass 44 cm at the wide end.

No 2C+H check for a house stair. DB-SUA 1 does carry a comfort formula. It keeps twice the riser (C) plus the going (H) between 54 cm and 70 cm. But §4.2.1 states it only for uso general stairs, the shared or public class. A home’s own stair skips it. The riser and going limits above are the whole rule.

Headroom has its own rule, in DB-SUA 2, §1.1. That is the impact section, not SUA 1. You need 2.10 m clear in restricted-use circulation zones. That means a home’s halls and landings. Other circulation zones need 2.20 m. A door threshold needs 2.00 m. The Ministry’s own note backs this up: the 2.10 m figure covers circulation zones only. It does not cover a living or sleeping room. So a sloped ceiling over a stair does not fail just because the room runs low somewhere else.

Handrail & guarding

The handrail (pasamanos) sits 90–110 cm above the pitch line. Read this one with care. The 90–110 cm figure sits in §4.2.4, the uso general clause. The house-stair clause (§4.1, point 4) asks for a handrail on any open side. It gives no height of its own. So the 90–110 cm figure gets used by common cross-reference. The code does not restate it for the house class.

Guarding (barreras de protección) protects a drop. DB-SUA 1 uses one rule for every kind of edge. Stair, landing, floor or balcony — the rule looks only at how far the drop is, not at what kind of edge it is (§3.2.1).

The gaps in the guarding matter too:

• No opening may let a 10 cm ball through. That figure covers homes, school zones, and public zones used for shops or assembly. Other public zones: 15 cm.
• A tread, a riser and a baluster’s lower edge can form a small triangle gap. That gap is exempt only if it sits 5 cm or less from the stair’s pitch line (§3.2.3).

Work it out on site

Say your floor-to-floor height is 2.80 m. You are setting out a house stair.

1. Pick the riser count. 2.80 m ÷ 0.20 m (the tallest a riser can be) = 14. That is a clean number. So: 14 risers, each 200 mm, right at the 20 cm cap.
2. Set the going. Try 220 mm, the minimum. Fourteen risers means 13 goings. So the stair runs 13 × 220 = 2860 mm along the floor. Check it fits the space. Spain sets no 2C+H check for this class. So a deeper going is a comfort call, your call, not a code one.
3. Check headroom and guards on their own. Confirm 2.10 m clear above the stair. Guard any open side to 0.90 m, or 1.10 m past a 6 m drop.

The calculator rounds the risers for you. It flags a riser past 20 cm or a going under 22 cm.

Do it in 5 seconds

Related

• Spanish Building Regulations hub: how the one national CTE and its Documentos Básicos work.
• Irish stair & barrier rules: handy if you compare riser and going rules across countries.

Sources

• CTE DB-SUA — Seguridad de Utilización y Accesibilidad, §4.1 (riser, going, restricted-use classification), §4.2.1 (2C+H formula, uso general only), §4.2.4 (handrail height, uso general), §3.2.1 (guard heights), §3.2.3 (guard-opening sphere rule), and DB-SUA 2 §1.1 (headroom). Read it at codigotecnico.org.

Read this first. These figures are from the current DB-SUA articulado (Real Decreto 450/2022, de 14 de junio, corrected BOE 02/02/2023). A further partial revision of the CTE affecting DB-SUA was in public consultation at the time these figures were checked (not yet adopted) — always confirm the current DB-SUA text at codigotecnico.org before you build to it.