Attic reg query

Bonzo Delaney

In the suggested height of habitable rooms of part f of the tgd .
In relation to the formula of

AreaB not less than Area A / 2
In an attic conv situation

Is this rule generaly seen as gospel or is there a bit of play here in the definition of a habitable room , as the term "suggested" is used
All other regs are in place re fire and structure
Theres a short fall of 2.6 sqm where the 2.4m height plane is of a width of 1.2m and the 1.5 m height plane is of 3.5m width & lenght of room is 4m

Just looking for peoples experience of getting around this with out putting a dormer in that includes the ceiling area of 2.6 sqm

Gas thing is if I made the room smaller by increasing the pitch of the rafter from the collar tie down to the floor using a false rafter, the maths would add up. But that defeats the purpose.
Thanks

Gumbo

Generally, if all other precautions are in place the head height is overlooked from a building control point of view.

Can your architect demonstrate alternative means of ventilation that over rules the volume calculation contained in Part F?

Calahonda52

Bonzo,
Hope all well with you.

One consideration is, notwithstanding the building control perhaps overlooking the height issue, there is the issue if the property is being sold as to whether it can be described as a habitable room.

I live in a converted dormer where the two bedrooms upstairs fail the habitable room test so when the houses in the estate are being sold they are shown as storage, with en-suites!

May not be an issue for you but unless you go with full disclosure it may bite your PI at some point

mickdw

It's a bit of a silly rule really.
for example, you could narrow the room up to 2.4m wide with stud work and you would be compliant yet have a much more useless space.

sydthebeat

mickdw wrote: »

It's a bit of a silly rule really.
for example, you could narrow the room up to 2.4m wide with stud work and you would be compliant yet have a much more useless space.

i dont read the rule like that mickdw

in essence it doesnt matter where the stud work walls are... the reg states that it must have a 2.4 ceiling width of over half of what it would be at 1.5

so its the shape of the triangular section of the roof thats affected.
and, in my opinion, it doesnt matter if the studs are at 600, 1200, 1500, 2100.. whatever

Bonzo Delaney

Calahonda52 wrote: »

Bonzo,
Hope all well with you.

One consideration is, notwithstanding the building control perhaps overlooking the height issue, there is the issue if the property is being sold as to whether it can be described as a habitable room.

I live in a converted dormer where the two bedrooms upstairs fail the habitable room test so when the houses in the estate are being sold they are shown as storage, with en-suites!

May not be an issue for you but unless you go with full disclosure it may bite your PI at some point

Good to see you back Cal
Thanks all for the replies
The regs state that " the suggested dimensions are consistent with good room design"
Which to me (I'm only a humble carpenter) read as there might be some " wiggle room" in the definition of a habitable room once, as Kceire suggested other factors were brought in to play to compensate for the shortfall in ceiling area.
I'm wondering has any one had experience/suggestions in this scenario to keep it defined as a saleable habitable room.
The back story is . ..on a major refurb of a house and the client sprung an attic conversion half way through. When this issue croped up and the dormer was suggested , both budget and time constraints with planning knocked it on the head.
I did suggest to make the room smaller to make the maths work like mickdw mentioned and they threatened to run me off the site.... he he

Calahonda52

Thanks, nice to be back amongst friends.:)
See attached to explain what happens in my estate, with a converted dormer bungalow.
Keep well.

mickdw

sydthebeat wrote: »

i dont read the rule like that mickdw

in essence it doesnt matter where the stud work walls are... the reg states that it must have a 2.4 ceiling width of over half of what it would be at 1.5

so its the shape of the triangular section of the roof thats affected.
and, in my opinion, it doesnt matter if the studs are at 600, 1200, 1500, 2100.. whatever

I don't know about that interpretation. Im possibly totally wrong but regulation refers to good room design - basically referring to the accommodation and if the vertical structural studs at room sides are placed at a position that creates a permanent space with 2.4m ceiling area greater than half the area at 1.5m high, you would have to imagine that satisfies the requirement in terms of room design.
What if one was to provide attic accommodation with full 2.4m ceiling height over entire accommodation down the centre of a large dwelling with a shallow pitch. Is it therefore possible that this room would not comply even though the entire habitable area created would have 2.4m ceiling?

Bonzo Delaney

mickdw wrote: »

I don't know about that interpretation. Im possibly totally wrong but regulation refers to good room design - basically referring to the accommodation and if the vertical structural studs at room sides are placed at a position that creates a permanent space with 2.4m ceiling area greater than half the area at 1.5m high, you would have to imagine that satisfies the requirement in terms of room design.
What if one was to provide attic accommodation with full 2.4m ceiling height over entire accommodation down the centre of a large dwelling with a shallow pitch. Is it therefore possible that this room would not comply even though the entire habitable area created would have 2.4m ceiling?

I cant see why that wouldn't pass Mick as the two surface plane area's would be equal , which it'd be more than half ,as in the elevation plan of the room itsself would be rectangular in shape whereas most attic rooms would be an irregular hexagonal shape with the 1.5 height requirement hitting on the internal roof slope
We could get bogged down in the various scenarios of roof pitch and unusable room sizes to make the maths work so to speak
But I suppose my question is ,since it falls under the ventilation section of the Tgd's can anything be added by means of ventilation to compensate for the shortfall in surface ceiling area .
That then qualifies the room as a defined habitable space.
Hypothetically speaking if the house was for sale as a 5 bed including the attic room. And the buyers surveyor discovered that surface B was less than half surface A so its only a 4 bed. Could the seller then say "we know but we have xy&z in place that compensates for that so the room still qualifies as a 5th bedroom" . In a put that in your pipe and smoke it kind of way.

mickdw

yes but that example is taking it to an extreme but if syds understanding is correct, it would have to be assessed based on possible space so 1.5m plain would be measured out to hit underside of roof thereby very likely making the accommodation non compliant.
I don't think that can be the correct interpretation myself.

sydthebeat

first of all im not evangelical about this at all because its only a "suggested" dimension.

howevere i come at it from the point of view that its there to offer good design solution at design stage
so really its there to offfer a good suggestion before the roof is built.

if you design and build a full 2.4 m high square room then id consider that a brand new full storey and not a "room immediately below the roof"

if its an attic conversion ie under an existing roof, then i think the regs should be a lot more lax, and once proper ventilation can be proven then the suggestion in question can be ignored to a certain degree, because there is no "good building design" to be suggested to... it already exists and the designer cannot influence it

mickdw

It's typical enough of the scale of house I see being built. You could have a collar tie at attic ceiling level of 4m easily. It's not difficult to image a 4m wide full height accommodation being constructed there.
It is still a room within the roof space and certainly a room immediately below the roof as much as any other dormer room is.