Doc M pack layout: key facts
- The Doc M layout comes from Approved Document M Volume 2, Diagram 18 (plan), Diagram 19 (heights, looking at the wall beside the WC) and Diagram 20 (other fittings). Para 5.10(i) and (l) point to them.
- In Diagram 18 the WC centre line is 500mm from the side wall, at least 1000mm from the opposite wall, and the front of the pan is 750mm from the back wall.
- The drop-down rail on the open side is 320mm from the WC centre line. All horizontal rails, including drop-down rails, are at 680mm above the floor (Diagram 19).
- The WC seat is 480mm high (subject to the pan's manufacturing tolerance) and the finger rinse basin rim is 720 to 740mm (Diagram 19).
- The flush goes on the open, transfer side whichever way the room is handed (para 5.10(r)). Diagram 18 is drawn for right-hand transfer; a left-hand room is its mirror image.
- The alarm pull cord has two red bangles, one at 100mm and one at 800 to 1000mm above the floor, and must be reachable from the WC and from the floor near it (Diagram 19, para 5.10(o)).
- The room in Diagram 18 is at least 1500mm wide by 2200mm long, not counting any projecting heat emitters. Getting the room right is a separate job from placing the fittings: see disabled toilet dimensions.
- Approved Documents apply in England. Wales, Scotland and Northern Ireland have their own rules. Check the final layout with your building control body or designer.
How does a Doc M toilet layout work?
The layout is built around one movement: a wheelchair user pulls up beside the WC, transfers across, uses the toilet, then washes and dries their hands without getting up. Every fitting position in ADM Diagrams 18 to 20 serves that sequence, so the WC position is fixed first and everything else is measured from it.
Approved Document M para 5.8 describes what the room has to do. A wheelchair user should be able to approach, transfer to and use the WC. The space beside the WC used for transfer should stay clear all the way to the back wall. The WC and finger rinse basin should be close enough that someone can wash and dry their hands while still seated.
That gives the drawing its shape. Diagram 18 puts the WC in a corner, against the back wall and close to one side wall (ADM calls this wall A). The basin, wall rail and alarm cord sit on wall A, within reach of the seat. The open side of the WC is left empty for the wheelchair, with a drop-down rail that folds out of the way. The door and the turning space are at the other end of the room.
Two reference lines do most of the work when you set out:
- The WC centre line, running out from the back wall through the middle of the pan. Side-to-side positions (rails, transfer space) are measured from it.
- The finished floor level. Every height in Diagram 19 and Diagram 20 is measured from the finished floor, not the screed.
Where does each fitting go on plan?
On plan, ADM Diagram 18 sets the WC centre line 500mm from wall A and at least 1000mm from the opposite wall, with the front of the pan 750mm from the back wall. The drop-down rail is 320mm from the WC centre line, and the vertical rail on the back wall is a further 150mm out.
These are the side-to-side and front-to-back positions shown in Diagram 18. It's drawn for right-hand transfer: flip it for a left-hand room.
| Fitting | Position on plan | ADM reference |
|---|---|---|
| WC (pan centre line) | 500mm from wall A | Diagram 18 |
| Transfer space | At least 1000mm from the WC centre line to the opposite wall, kept clear to the back wall | Diagram 18, para 5.8 |
| Front of WC pan | 750mm from the back wall | Diagram 18 |
| Drop-down rail (open side) | 320mm from the WC centre line | Diagram 18, para 5.8 |
| Vertical grab rail on back wall (open side) | 150mm beyond the drop-down rail (970mm from wall A) | Diagram 18 |
| Horizontal grab rail on wall A | Shown 600mm long, starting 250mm from the back wall. Its distance from the WC decides whether you need a second drop-down rail (see below) | Diagram 18, para 5.10(j), (k) |
| Finger rinse basin | On wall A, just beyond the front of the pan, so it can be reached from the seat | Diagram 18, para 5.8 |
| Vertical grab rails at the basin | On wall A, beside the basin | Diagram 18 |
| Flush | On the open (transfer) side, whatever the handing | Para 5.10(r) |
| Sanitary disposal unit | Beside the WC, on the wall A side | Diagram 18 |
| Alarm pull cord | On wall A near the WC, or the alternative position on the back wall on the transfer side | Diagram 18, para 5.10(o) |
| Mirror and clothes hooks | On the side wall opposite wall A | Diagram 18 |
| Shelf, disposal bin, sanitary dispenser | Near the door, on the wall A side | Diagram 18 |
| Wheelchair turning space | 1500mm by 1500mm, between the door and the WC | Diagram 18 |
Diagram 18 also shows two small dimensions (140 to 160mm by the basin and 60 to 85mm by the wall rail). Read those off the diagram itself in the current GOV.UK PDF when you mark out, as they control fine positions near the pan.
Wall A rail with its centre line 400mm from the WC centre line: no extra rail needed.
Wall A rail at the minimum spacing from the wall: add a second drop-down rail on the wall side, 320mm from the WC centre line.
Mark this decision on the drawing before ordering, because it changes what you buy.
What heights do the fittings go at?
ADM Diagram 19 puts the WC seat at 480mm, horizontal and drop-down rails at 680mm, the finger rinse basin rim at 720 to 740mm, and the vertical rail by the WC centred at 1100mm. Diagram 20 covers mirrors, separate basins and the hand dryer.
All heights are from the finished floor. Diagram 19 is drawn looking at wall A, the wall beside the WC.
| Fitting | Height above finished floor | ADM reference |
|---|---|---|
| WC seat | 480mm (subject to the pan's manufacturing tolerance) | Diagram 19 |
| Horizontal grab rails | 680mm | Diagram 19 |
| Drop-down rail(s) | Same height as the other horizontal grab rails | Diagram 19 note |
| Vertical grab rail by the WC (wall A) | Centred at 1100mm, running 300mm above and 300mm below | Diagram 19 |
| Finger rinse basin rim | 720 to 740mm | Diagram 19 |
| Alarm pull cord bangles | Two red bangles: one at 100mm, one at 800 to 1000mm | Diagram 19, para 4.30(e) |
| Shelf by the WC | 950mm | Diagram 19 |
| Sanitary dispenser coin slot | 750 to 1000mm | Diagram 19 |
| Soap and paper towel dispensers | Shown above the finger rinse basin (no separate height given) | Diagram 19 |
| Toilet paper dispenser and alarm reset button | Shown on wall A above the horizontal rail by the WC (no separate height given) | Diagram 19, para 5.4(h) |
| Automatic hand dryer | Underside at 800 to 1000mm; Diagram 19 shows a possible position on wall A | Diagrams 19 and 20 |
| Separate washbasin | Rim 780 to 800mm for people standing; 720 to 740mm for use from the WC | Diagram 20 |
| Mirror over a separate basin | Top at least 1600mm, with a 600mm vertical rail each side, rails 600 to 700mm apart and centred at 1100mm | Diagram 20 |
| Mirror away from a basin | Bottom at 600mm, top at least 1600mm, so seated and standing people can use it | Diagram 20 |
The dispensers and the reset button have no stated height in the diagram, but they still have to work for someone seated on the WC: para 5.8 says the user should be able to wash and dry hands from the WC, and para 5.4(h) says the alarm reset should be reachable from the wheelchair and the WC. Position them by testing the reach, not by copying a standard washroom.
How do left-hand and right-hand transfer layouts differ?
A left-hand transfer layout is the mirror image of a right-hand one. Diagram 18 is drawn for right-hand transfer; swap the sides and every measurement stays the same. ADM wants both handings available in buildings with more than one accessible toilet.
Some wheelchair users can only move across from one side. That's why ADM asks for a choice:
- In a multi-storey building, accessible toilets in a similar position on each floor, with right- and left-hand transfer on alternate floors (para 5.10(c)).
- Where there is more than one unisex accessible toilet in a building that isn't multi-storey, a choice of left- and right-hand layouts (para 5.10(d)).
Flipping the layout
- Take Diagram 18 and mirror the whole plan left to right, so wall A and the transfer space swap sides.
- Keep every dimension: 500mm to wall A, at least 1000mm to the transfer-side wall, 750mm to the front of the pan, 320mm to the drop-down rail.
- Move the flush with it. It must stay on the open, transfer side (para 5.10(r)), which usually means a cistern or flush plate of the other hand.
- Move the alternative pull cord position to the back wall on the new transfer side.
- Label the drawing with a plan sketch, not just "LH" or "RH". Suppliers and installers don't all name handing the same way.
Where the soil stack is often decides the handing. On a new building, agree the handing for each floor at design stage so the drainage goes in the right place first time.
Where should the door go, and how does the corridor affect the layout?
Diagram 18 shows the door in the wall facing the WC, opening outwards, with an alternative position in the side wall opposite wall A. The door's clear width depends on how it's approached from the corridor (ADM Table 2), and the door swing must not eat into the turning space.
The door is where most whole-room layouts go wrong, because it's fixed by the corridor and structure before anyone thinks about the WC.
Door position inside the room
- End wall, facing the WC: the main position in Diagram 18. It gives a straight run into the turning space.
- Side wall, opposite wall A: the alternative position in Diagram 18, near the door end of the room. Useful when the room runs along a corridor.
- Outward opening is preferred, with a horizontal closing bar on the inside face (para 5.10(g)). If a door has to open in, its swing must not encroach on the wheelchair turning space or the minimum activity space (para 5.3).
- The door needs a light-action privacy bolt and an emergency release so it can be opened from outside (para 5.4(d), (e)).
Approach from the corridor
Straight-on approach: 800mm new building, 750mm existing building.
Turning in at right angles from a route at least 1500mm wide: 800mm new, 750mm existing.
Turning in at right angles from a route at least 1200mm wide: 825mm new, 775mm existing.
The corridor also matters beyond the door. The toilet should be on a direct, obstruction-free accessible route (para 5.10(f)), as close as possible to the entrance or waiting area (para 5.10(a)), and within the travel distances in para 5.10(h). Approved Document T para 1.21 adds that it should be reached from a primary circulation route, not through the men's or women's toilets. Our disabled toilet regulations guide covers where and how many.
How do you set out a Doc M toilet on site?
Fix the finished floor level and the WC centre line first, then mark every other fitting from those two lines using Diagrams 18 to 20. Check the room size, door and drainage before marking, and get the wall backing in at first fix.
- Check the room against Diagram 18: at least 1500mm wide (not counting any projecting heat emitters) and 2200mm long, or 2000mm wide where it is the only toilet in the building (para 5.10(e)). If it's short, stop and talk to the designer (room sizes are covered in our disabled toilet dimensions guide).
- Confirm the handing from the drawing and which wall is wall A. Check it against the soil connection.
- Agree the finished floor level, including tiles and any screed. Mark a datum line on the walls so every height can be measured from it.
- Mark the WC centre line 500mm from wall A, square off the back wall. Check there is at least 1000mm from it to the opposite wall.
- Mark the pan front 750mm from the back wall. If the cistern is boxed in, measure from the finished face of the boxing.
- Mark the rails: drop-down rail 320mm from the WC centre line; vertical rail on the back wall 150mm further out; wall A rail at 680mm high, with its distance from the WC agreed (400mm centre to centre, or minimum wall spacing plus a second drop-down rail).
- Mark the basin and its rails on wall A beyond the pan front, rim at 720 to 740mm. Sit-test the reach on a chair at seat height if you can.
- Mark the alarm cord, reset and outside signal positions and pass them to the electrician. Alarm wiring is electrical work for a competent electrician working to BS 7671.
- Mark the heat emitter clear of the turning space and the transfer space (para 5.10(p)).
- Fit backing behind every rail, the basin and the drop-down rail fixings at first fix, using the fixing instructions for the products you've bought.
- Measure again after tiling and before fixing, then record the as-fitted positions for the handover file.
Use the current GOV.UK PDF of Approved Document M Volume 2 (2015 edition incorporating 2020 and 2024 amendments) on site, not a supplier sheet or an old print. Always check the final layout with your building control body or designer.
What are the most common Doc M layout mistakes?
Most layout faults are things placed in the transfer or turning space, a WC set too far from wall A, rails at the wrong height or spacing, a flush on the wrong side, a basin out of reach of the seat, and an alarm cord that can't be reached from the floor.
| Mistake | What ADM shows instead | Reference |
|---|---|---|
| Bin, radiator, nappy changer or storage beside the WC | Transfer space clear to the back wall; heat emitters out of the transfer and turning spaces; no baby changing in a wheelchair-accessible unisex toilet | Paras 5.8, 5.10(p), 5.5 |
| WC centred on the room or pushed away from wall A | WC centre line 500mm from wall A, so the wall rail and basin are in reach | Diagram 18 |
| Transfer space narrowed by boxing or a pipe chase | At least 1000mm from the WC centre line to the opposite wall | Diagram 18 |
| Drop-down rail at a different height to the wall rail | Drop-down rails at the same height as the other horizontal rails (680mm) | Diagram 19 |
| Wall rail tight to the wall with only one drop-down rail | Either a 400mm centre-to-centre wall rail, or a second drop-down rail 320mm from the WC centre line | Para 5.10(j), (k) |
| Flush on the wall side after flipping the layout | Flush on the open, transfer side whatever the handing | Para 5.10(r) |
| Basin in the opposite corner | Finger rinse basin on wall A, reachable from the WC | Para 5.8, Diagram 18 |
| Pull cord tied up or stopped short of the floor | Red cord with bangles at 100mm and 800 to 1000mm, reachable from the WC and the floor | Diagram 19, paras 4.30(e), 5.10(o) |
| Only mirror set too high to use from a wheelchair | A mirror away from the basin from 600mm to at least 1600mm, on the wall opposite wall A | Diagrams 18, 20 |
| Door swinging into the turning space | Outward opening preferred; any inward swing kept out of the turning space | Paras 5.3, 5.10(g) |
| Every accessible toilet the same hand | Left and right hand on alternate floors, or a choice where there's more than one | Para 5.10(c), (d) |
Many of these appear after handover, not at building control sign-off. Facilities teams should walk the room regularly: check the transfer space is clear, the cord hangs free and nothing has been added under the drop-down rail.
What if the room can't match the Doc M drawing exactly?
In an existing building you may not be able to hit every dimension. Approved Document M shows one way to comply, so talk to your building control body and designer before you build. Outside England, use the guidance for the nation where the building is.
Refits often meet a fixed soil stack, a narrow room or a door in the wrong wall. Before you compromise:
- Protect the transfer space and the WC-to-wall A dimension first. These are what let someone transfer and reach the rail and basin.
- Look at moving the door to the alternative side-wall position in Diagram 18 before shrinking the turning space.
- Agree any departure with building control in writing. ADM para 0.20 says the Approved Document shows only one way to meet Part M and other approaches can be used, but they need to be agreed.
- For ambulant cubicles inside the men's and women's toilets, the layout is different: see Diagram 21 and our ambulant toilet guide when it's published.
Wales, Scotland and Northern Ireland
Approved Document M is guidance for England. Wales publishes its own Approved Document M, Scotland uses the Building Standards Technical Handbook (Non-domestic), and Northern Ireland uses Technical Booklet R. The layouts may look similar, but check the measurements in the document that applies where your building is.
Related guides
Doc M pack layout: frequently asked questions
What is a Doc M pack layout?
It is the arrangement of the WC, basin, grab rails, flush, alarm cord and accessories shown in Approved Document M Volume 2, Diagrams 18 to 20. The WC sits in a corner with a clear transfer space on one side, and everything else is placed so a wheelchair user can reach it from the WC.
How far should the WC be from the wall in a Doc M toilet?
ADM Diagram 18 shows the WC centre line 500mm from the side wall next to it. There should be at least 1000mm from the WC centre line to the opposite wall, and the front of the pan is 750mm from the back wall.
What height is a Doc M toilet seat?
Diagram 19 shows the seat at 480mm above the finished floor, subject to the manufacturing tolerance of the WC pan. The pan should also take a variable height seat riser (ADM para 5.10(q)).
What height are Doc M grab rails?
Horizontal grab rails are at 680mm, and drop-down rails should be at the same height. The vertical rail on the wall beside the WC is centred at 1100mm and runs 300mm above and below that point.
How far is the drop-down rail from the toilet?
Diagram 18 puts the drop-down rail on the open side 320mm from the WC centre line. If the wall-side rail is at the minimum spacing from the wall, ADM asks for a second drop-down rail on the wall side, also 320mm from the WC centre line.
What height is the basin in a Doc M toilet?
The finger rinse basin by the WC has its rim at 720 to 740mm. A separate basin for standing users, needed where the toilet is the only one in the building, has its rim at 780 to 800mm (Diagram 20).
Where does the flush go on a left-hand transfer Doc M toilet?
On the open, transfer side, whichever way the room is handed (ADM para 5.10(r)). When you flip a right-hand layout to left-hand, the flush moves with the transfer space.
Where should the alarm pull cord be?
Diagram 18 shows it on the wall beside the WC, with an alternative position on the back wall on the transfer side. It is red, with bangles at 100mm and 800 to 1000mm above the floor, and must be reachable from the WC and from the floor near it.
What height should the hand dryer be in a disabled toilet?
ADM Diagram 20 shows an automatic hand dryer with its underside at 800 to 1000mm above the floor, and Diagram 19 shows a possible position on the wall beside the WC. Check it can be used by someone seated.
Can the door open inwards on a Doc M toilet?
ADM prefers outward opening doors with a horizontal closing bar on the inside. If the door opens inwards, its swing should not encroach on the wheelchair turning space or minimum activity space (para 5.3).
Does the Doc M layout apply in Scotland, Wales and Northern Ireland?
Approved Document M is guidance for England. Wales, Scotland and Northern Ireland have their own building regulations and guidance, so check the document that applies where your building is.
Sources
We checked the facts on this page against these sources on 12 November 2026: