Cutting a new stair opening in a floor
A new staircase means cutting joists and re-routing their load into trimmer beams. Our assessment reviews the floor build-up, the proposed opening and the supports it will need.
What the assessment covers
- • Floor construction: timber joists, concrete slab, beam and block, hollowcore
- • Joist direction and span relative to the proposed opening
- • Trimming and trimmer requirements, and where their loads land
- • Headroom, going and rise implications flagged against Part K expectations
What you send us
- • Photos of the ceiling below and the floor above, plus any exposed joists
- • Existing plans and the proposed staircase position
- • Opening dimensions and floor thickness if known
- • Property age and what the floor supports (loft, habitable room, storage)
What you receive
- • Indicative risk level and confidence rating
- • Budget range for the structural works
- • Watch points: joist hangers, notching limits, fire separation, headroom
- • Whether engineer's calculations and a building regulations application are expected
Avertissement légal
Ce document est informatif. Il ne constitue ni une note de calcul, ni un diagnostic réglementaire, ni une validation d'exécution de travaux. Aucun avis produit par la plateforme ne constitue une note de calcul, un diagnostic réglementaire ou une validation d'exécution de travaux. Aucune décision de travaux ne doit être prise sans validation par un professionnel qualifié (architecte, bureau d'études structure, ingénieur).
Frequently asked questions
Can I cut joists myself?
Cutting structural joists without trimming them correctly is one of the most common causes of floor deflection and cracking. Any opening wider than a single joist bay should be designed by a structural engineer.
Does a loft conversion staircase need building control?
Yes. Loft conversions are notifiable works and the new floor, staircase, fire escape route and protected stairwell are all assessed by building control.