Accessibility Adaptations for the Home: What You Can Do and What It Costs

A wet room — a fully waterproofed, level-access shower room — is the most commonly requested structural accessibility adaptation for London homes, and also one that adds genuine value to the property regardless of the specific accessibility driver.

**What a wet room conversion involves**: Converting an existing bathroom to a wet room requires: 1. Strip-out of existing bath, shower enclosure, and floor finishes 2. Forming a linear drain (channel drain) across the shower area — recessed into the structural floor 3. Tanking the floor and walls with a waterproof membrane system (typically a cementitious tanking slurry or a proprietary tanking board system such as Wedi or Marmox) 4. Laying a continuous floor tile or slip-resistant safety vinyl with a gentle fall to the drain 5. Fitting a fixed or fold-down shower seat 6. Installing a thermostatic shower valve (allowing safe temperature control — essential for users with reduced sensation) 7. Fitting a shower head on a height-adjustable rail 8. Appropriate grab rails at the entry point and within the shower area (to BS 8300:2018)

• **Floor construction for wet rooms**:
• Wet rooms are significantly easier to form on concrete ground floors (solid slab construction — common in newer builds and flat conversions). On suspended timber floors (the majority of older London terraces), creating a level-access wet room requires either:
• •Cutting a rebate in the floor joists to receive the drain body and set the floor finish at the correct level — structurally complex and requiring careful structural assessment
• •Raising the floor level in the adjacent bedroom or landing to match, creating a step-free transition from both directions
• •Replacing the timber suspended floor with a concrete topping within the room

• **Costs for wet room conversion (London 2025, contractor labour and supply of standard tiles and fittings, client supplies sanitary ware)**:
• •Ground floor concrete slab, existing bathroom conversion (no structural floor alteration): £8,000–£14,000
• •Upper floor suspended timber, requiring floor level modification or joist rebating: £12,000–£20,000
• •New wet room in a house extension (designed from scratch): £10,000–£18,000

• Part M (Access to and Use of Buildings) of the Building Regulations sets minimum clear opening widths for door openings:
• •New-build: 775mm clear opening width for doorways accessed by wheelchair users (a standard 826mm wide door in an 838mm frame delivers this)
• •Refurbishment: 750mm clear opening is the minimum recommended in BS 8300:2018

Most internal doors in Victorian and Edwardian London terraces were built to 686mm wide — approximately 650mm clear opening — significantly narrower than the BS 8300 recommendation. Widening these openings is a structural intervention where the opening is in a load-bearing wall.

• **What widening a doorway involves**:
• •Structural survey to confirm whether the wall is load-bearing
• •If load-bearing: design for a lintel or RSJ above the new, wider opening (structural engineer input required)
• •Building Control approval if the work constitutes a structural alteration
• •Careful phasing with other works — if the door is on a staircase wall, structural continuity during construction must be maintained

• **Level thresholds**:
• External doors, and doors between the house and an accessible extension or annex, should have level thresholds — eliminating the step that most Victorian properties have at the external door. This requires either:
• •Excavating and forming a ramp approach to bring the external ground level to match the internal floor level
• •Or — more practically in most London terraces — designing the accessible approach (ramp) to eliminate the change in level over a sufficient distance (maximum gradient 1:12 for ramps in public buildings; 1:12 to 1:20 for residential)

• **Costs (London 2025)**:
• •Single doorway widening (non-structural): £600–£1,200
• •Single doorway widening (structural, with lintel): £1,500–£3,500
• •External access ramp (concrete, 1.2m wide, standard gradient): £2,500–£5,000
• •Level threshold to external door (excavation and formation): £1,200–£2,500

Where a user cannot safely use the stairs but needs access to upper floors, the two main solutions are a through-floor lift or a stairlift. The choice depends on the user's mobility, the property's structural configuration, and budget.

**Stairlift**: A stairlift fits a motorised seat onto a rail mounted to the stair strings. It is the least structurally invasive option — no floor penetration or major structural work. The rail is bolted to the stair treads, not the walls.

**Pros**: Fast installation (1–2 days), relatively low cost (£2,000–£6,000 for a straight stairlift, £5,000–£12,000 for curved stair), reversible **Cons**: The user must be able to transfer on and off the seat independently or with assistance; the stairlift occupies width of the stair and may make it difficult for others to pass; unsuitable if the user cannot sit safely without support

**Through-floor lift (platform lift)**: A through-floor lift creates a vertical opening in the first floor and installs a small platform cab that carries the user from ground to first floor level. It requires a structural opening in the floor (and potentially relocation of structural elements), and a structural engineer's sign-off.

**Floor opening requirements**: Typically 800mm × 1,000mm minimum clear platform size; floor opening approximately 900mm × 1,100mm **Structural implications**: Floor joists must be trimmed (cut and supported) around the opening; a 'trimmer joist' and 'trimming joist' must carry the point loads created by the opening — standard structural carpentry if the opening is positioned to avoid significant structural interruption **Building Regulations**: The installation of a through-floor lift is notifiable under Part K (Protection from falling, collision, and impact) — building control approval and completion certificate required

• **Costs (London 2025, including structural opening and installation)**:
• •Straight stairlift: £2,000–£6,000 (supply and fit)
• •Curved stairlift: £5,000–£12,000 (supply and fit)
• •Through-floor platform lift (supply, structural opening, install): £12,000–£25,000

**Disabled Facilities Grant (DFG)**: Homeowners and private tenants in England can apply to their local council for a Disabled Facilities Grant to fund accessibility adaptations. The maximum mandatory grant is £30,000 (England). The grant is means-tested for adults over 16. A formal assessment by an Occupational Therapist (OT) is typically required to confirm the recommended adaptations and support the grant application.

• **Part M of the Building Regulations**:
• Part M (Access to and Use of Buildings) applies to:
• •All new dwellings (must meet Requirement M4(1) as a minimum — Visitable Dwellings — or M4(2) / M4(3) if specified by the local planning authority)
• •Material change of use or material alteration of an existing dwelling where the change triggers Part M compliance

For most domestic adaptation projects, Part M does not automatically trigger a full compliance review — but where Building Control is engaged for structural works (widened doorways, floor openings), the opportunity should be taken to ensure the adaptation meets BS 8300:2018 accessibility standards.

• **Planning permission for accessibility adaptations**:
• Most accessibility adaptations inside the property (wet rooms, widened doorways, through-floor lifts) do not require planning permission — they are alterations within the existing building envelope. Exceptions:
• •Access ramps or platform lifts that project beyond the building line and are visible from the highway — these may require planning permission
• •Adaptations in Conservation Areas that change the external appearance of the property
• •Any structural addition or extension that goes beyond the existing building footprint

• **Future-proofing principle**:
• For clients in their 40s or 50s who are not currently planning for a disability but are carrying out a major refurbishment, specifying accessibility features during the main project (rather than retrospectively) significantly reduces whole-life cost:
• •Designing a wet room rather than a bath in a ground-floor bathroom (minimal additional cost during construction; very expensive to retrofit)
• •Designing doorways to 826mm width (826mm door rather than 762mm — typically no additional cost)
• •Ensuring a ground-floor space large enough to become a bedroom if needed in the future
• •Designing the electrical layout to allow future installation of a through-floor lift without major rewiring