Michael Tweed B.A. B.Arch RIBA MRIAI
In the course of my work I am dealing with a planning permission from a local authority planning department which has the following condition: “That any attic floorspace which does not comply with Building Regulations in relation to habitable standards shall not be used for human habitation”.
My first reading of this was to assume that it referred to Diagram 3 in TGD F Ventilation where the recommended ceiling height for an attic space is described, and to the definition of “habitable room” in the same TGD as a room in a dwelling used for sleeping purposes but doesn’t include a kitchen having a floor area of less than 6.5sqm. But several problems arise from this condition. Firstly it is impossible to find a definition of “habitable standards” in the Building Regulations. The planning permission is a document with information as much for the house owner as for his/her architect and builder but this is a condition impossible for him/her to understand because he/she will find not be able to find “habitable standards” in the Building Regulations. Secondly the condition, if it could be properly understood is impossible to police.
But most concerning of all it gives rise to a “cheat” which could ultimately cause loss of life.
The Condition as written is an example of the sloppy shorthand that’s common in the building industry. (A long time bugbear of mine is the use of the term “requirements of the Building Regulations” when what is actually referred to are the requirements in the Technical Guidance Documents). In regard to the above planning Condition let’s begin with the simple question, what are “habitable standards”? I’ve read the Building Regulations, or to be precise the Second Schedule to the Building Regulations which are the regulatory requirements for buildings, and nowhere is the term “habitable standards” either defined or used.
Presumably the author of that condition was referring to the definition of “habitable room” as given in Part F TGD and more particularly to Diagram 3 in the same TGD showing “suggested heights of habitable rooms”.
To digress somewhat from my main concern for a moment, Part F is the only TGD to suggest any guidance regarding ceiling heights of habitable rooms. However, the reason for limiting ceiling height to 2.4m provided in TGD F quite frankly doesn’t stand up to scrutiny. To suggest that ceiling height is a factor which affects ventilation shows a complete lack of understanding of ventilation – but then most of TGD F demonstrates that lack of understanding of ventilation from beginning to end.
2.4m as a minimum ceiling height for a habitable room is laudably good design – that’s all. It’s good design because the major percentile of people are shorter than 2.05m high (the clearance height of a standard door head) and therefore when you suspend a light fitting from a 2.4m ceiling it won’t clatter most people on the head. I can’t come up with any other cogent reason for such a limit.
Dropping the ceiling from 2.4m to 2.1m will still provide a usable room for everyone who can comfortable pass through a standard 2.05m door opening without ducking their head. But generally it WON’T affect the ventilation in that room if it is well ventilated to begin with.
Inclusion of a ceiling height of 2.4m as a recommendation for a habitable room in a TGD makes the limit of 2.4m advisory, not mandatory. I am happy for 2.4m to be a mandatory ceiling height limit defining a habitable room, but to be mandatory it needs to be made a statutory requirement.
However making 2.4m a statutory height limit doesn’t actually address what I see as the risk to life of attic conversions, in particular conversions of attics in a two storey dwelling. In this case an attic conversion extends the dwelling by a storey height.
There are several fairly onerous requirements in regard to fire safety in adding the extra storey. By limiting the definition of “habitable space” to a certain geometry and headroom, attic conversions often end up being defined as “storage space” rather than “habitable space”.
The fact is that most attic conversions are carried to provide an extra bedroom, either for a member of the occupant’s family or as a guest room; they are NOT carried out to provide storage space. Regardless of it being defined as a “storage space” simply because it is not deemed to accord with Diagram 3 of TGD F, and the probability that in a future house sale the sales brochure will describe the attic as storage rather than an additional bedroom, it doesn’t alter the fact that the attic will be used as a “habitable space”. Architects, engineers, surveyors and builders need to exercise their professional responsibilities and duty of care in this regard. When they know an attic is being converted for use as a habitable room it is dishonest and dangerous to pretend otherwise!
TGD Part B doesn’t require an attic conversion for storage space use to be built to the same high standards as habitable accommodation. Section 1.5.7 (Loft Conversions) specifically states that in the “case of an existing two storey dwelling to which a storey is to be added by converting the existing room space into habitable accommodation, the following provisions can apply….”. The corollary of that is that in the case of conversion of an attic as a non-habitable space those provisions don’t apply.
An attic space defined as “storage space” will not be constructed to the standards required in TGD B for habitable accommodation. When used for accommodation the users are patently at risk in the event of a fire. To knowingly define the attic as storage space when in fact it will be a habitable room and to be complicit in putting the occupants at risk in this way is totally unacceptable.
Perhaps it might be better to change the requirements of TGD B for loft conversions whereby any conversion which upgrades access into the attic and includes flooring the attic space imposes ALL the requirements currently required for habitable accommodation.
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