The relevant Building Regulation is Part M, section applicable to Existing Dwellings.

#1 - Essentially you can not alter a doorway to make it worse than it was before, this is pretty general across building regulations when push comes to shove.

#2 - If the bedrooms are not on the Principal Storey then the matter becomes even less important.

#3 - If the bedrooms are on the 3rd Storey or multiple occupancy you hit other issues.

Frankly Part M should be watered down, and instead a set # of houses within a catchment area should comply fully with Part M either a) as new houses are built or b) as conversion. Building Regs are increasingly creating a ridiculous overhead - and I have two relatives wheelchair disabled so understand very well.


The solution is a temporary structure which is easily removed at house sale or if someone were to become disabled. Note that is not "temporary" in legal terms, simply so you can reverse it at a future date.

It is very common for upstairs landing & bathroom & toilet access to be 650mm wide - which utterly eliminates any chance of wheelchair access. To increase that access to that required (900mm wide corridor for Direct Approach) you need to move the walls inwards. Even if that is physically possible (built on floors) it may require a) substantial joist reinforcement to comply with BR "A" and even new ceilings where they are differing heights or b) put walls in front of bay windows. Imbecile councils have ended up with "b)", one house subject to such is now derelict as no money to reverse the conversions as the person moved into care (forced into care by an O/T on grounds of Council Policy and her ownership in the relevant Care Agency she mandated, too costly to challenge).