maximising attic

[peachpeach 2]

dear experts, 

my proposed attic seems abit small and i was told that  the attic cannot protrude out of the 45deg slopping line. is there any other way to maximise it

[snoozee 98]

Can only be within the 45 degree envelope defined by URA. but no need to die die have the roof pitch touch the corner of the lower storey. 
 

Can do something like this

      ________
___|             |___
|                        |
 

you can then do a canopy about 1M or 1.5m from the top to shade the balconies front and back

[yoongf 11]

https://www.ura.gov.sg/Corporate/Guidelines/Circulars/dc19-08

[peachpeach 2]

hi snooze, can i check. say if the archi is only managed to built 1000 sqft on attic. how much more gfa can ur drawing yield?

[snoozee 98]

firstly, I must clarify that I do not know how your architect had designed the roof profile.

assuming that the area within the 45 degrees pitch lines are currently not utilised as indoor areas and you have a 3.5m height for the attic, you could possibly get another 6sqm (64sqf) each for front and back (assuming your plot is 6m wide, and 1m extension).

again I must emphasize that I am assuming a lot of things here as I do not know your land dimensions and roof profile which is being designed.

edit: referring to the below diagram, area in green is the extension which can be gained by doing the step roof. based on my understanding of URA and BCA requirements, the 1m drop is the max allowed so as to still obtain a min 2.4m floor to ceiling clearance required by BCA while still maintain the build structures (wall/column) within the buildable envelope demarcated by the springing lines.

 

Edited January 21, 2020 by snoozee
added diagram

[3Cube 9]

I did a simplify diagram.

Example 1 shows ceiling board & roof install together at same level (Assume maximum 5 m from Attic). After factoring the 45 degree spring line your allowed floor area is as shown.

Example 2 shows Roof level remains but Ceiling is lower down, Floor area increase.

Please note this is not the only criteria. Just serve to explain the concept of Spring Line in relation to height which affect the floor area

In layman's term, Whatever you can build must be confine within the trapezoidal boundary (roof line, attic floor line & both the front & rear 45 degree spring line)

Edited January 21, 2020 by 3Cube
Addition information

[3Cube 9]

The following is another advise which I think you should understand.

Increase in floor area "might" in turn affect your property tax.

Let me explain:

Property Tax is based on your property’s annual value.

The way IRAS estimates your property’s annual value is by taking an estimate of how much rental income your property can fetch in the year. In other words, IRAS is taking your property’s rental potential as an estimate of its annual value.

And rental value increase in direct relation with floor area (1 of the criteria, of course there are other factor such as location, etc). For example, rent for a 2000 sq ft landed property will be theoretically be lower than a 3000 sq ft landed property, assuming all other factor such as location, condition of property remain unchanged.

If you had engage an architect, I'm sure most of the time the architect will try to maximize the potential of the land usage.

[snoozee 98]

1 hour ago, 3Cube said:

I did a simplify diagram.

Example 1 shows ceiling board & roof install together at same level (Assume maximum 5 m from Attic). After factoring the 45 degree spring line your allowed floor area is as shown.

Example 2 shows Roof level remains but Ceiling is lower down, Floor area increase.

Please note this is not the only criteria. Just serve to explain the concept of Spring Line in relation to height which affect the floor area

In layman's term, Whatever you can build must be confine within the trapezoidal boundary (roof line, attic floor line & both the front & rear 45 degree spring line)

you may wish to check your URA guidelines again on where the spring line starts for attics under the envelope control guidelines.

[3Cube 9]

55 minutes ago, snoozee said:

you may wish to check your URA guidelines again on where the spring line starts for attics under the envelope control guidelines.

I stand correct.

As this forum seems to hide weblink. Go to URA site, Guideline, Development Control, Semi-Detached Houses, Envelope Control Guidelines.

You will be able to see the 3D diagram proving I'm correct.

[snoozee 98]

1 hour ago, 3Cube said:

I stand correct.

As this forum seems to hide weblink. Go to URA site, Guideline, Development Control, Semi-Detached Houses, Envelope Control Guidelines.

You will be able to see the 3D diagram proving I'm correct.

you indicated a max 5m height for attic and your spring line started from the corner based on 5m height which isn't what URA is depicting. the 5m max height is before envelope control and with all new developments falling under envelope control, the 5m max height is no longer applicable.

if you look more clearly into details of the URA residential guidebook on envelope control and click on the section on attics rather than just looking at the main 3D diagram, you will see how the envelope is being defined from the section view and how the spring line is based from 3.5m from the permissible building height and not based on 5m. with the spring line based on 3.5m instead of 5m, you can actually get more floor space since the setback of the roof from the building front and back is now 3.5m instead of 5m which essentially gives additional 3m of useable internal floor space assuming the roof is at the max allowed height.

[3Cube 9]

8 hours ago, snoozee said:

you indicated a max 5m height for attic and your spring line started from the corner based on 5m height which isn't what URA is depicting. the 5m max height is before envelope control and with all new developments falling under envelope control, the 5m max height is no longer applicable.

if you look more clearly into details of the URA residential guidebook on envelope control and click on the section on attics rather than just looking at the main 3D diagram, you will see how the envelope is being defined from the section view and how the spring line is based from 3.5m from the permissible building height and not based on 5m. with the spring line based on 3.5m instead of 5m, you can actually get more floor space since the setback of the roof from the building front and back is now 3.5m instead of 5m which essentially gives additional 3m of useable internal floor space assuming the roof is at the max allowed height.

I agree.

But I did state that "Maximum" height is 5M.  I fail to mention some estate only have allowable overall height of 12 M, while other have 15 M. So it depends on the location of the estate; which determine the individual storey height.

I've personally designed, submitted, received approval from authorities & completed TOP (Hands on doing the design drawing)

I just submitted another plans that my architect had checked base on the principle in the concept diagram.

In my diagram as presented earlier, there are other elements which I omitted due to time constraint as I was rushing off, which you had shown. Such as the extended area with lower ceiling / roof at front & back. But I did mentioned "Whatever you can build must be confine within the trapezoidal boundary"

I'm only trying to explain it with diagram as I think your earlier post explaining in words did not convey the idea to layman.

 

I've no agenda against anyone. Just trying to help by simplifying the idea by presenting a diagram. I will try to allocate more time to clear & correctly help out in future postings.

Edited January 21, 2020 by 3Cube
Addition information

[snoozee 98]

9 hours ago, 3Cube said:

I agree.

But I did state that "Maximum" height is 5M.  I fail to mention some estate only have allowable overall height of 12 M, while other have 15 M. So it depends on the location of the estate; which determine the individual storey height.

I've personally designed, submitted, received approval from authorities & completed TOP (Hands on doing the design drawing)

I just submitted another plans that my architect had checked base on the principle in the concept diagram.

In my diagram as presented earlier, there are other elements which I omitted due to time constraint as I was rushing off, which you had shown. Such as the extended area with lower ceiling / roof at front & back. But I did mentioned "Whatever you can build must be confine within the trapezoidal boundary"

I'm only trying to explain it with diagram as I think your earlier post explaining in words did not convey the idea to layman.

 

I've no agenda against anyone. Just trying to help by simplifying the idea by presenting a diagram. I will try to allocate more time to clear & correctly help out in future postings.

landed houses in 2 storey zone has a max height limit of 12m while houses in 3 storey zone has a max height limit of 15.5m. URA don't control the individual storey height for envelope control but BCA still requires a minimum of floor to ceiling height clearance of 2.4m. so a 2 storey house can be built with 2 storey with an attic and mezzanine within the 12m envelope as long as all storeys can clear the 2.4m floor to ceiling requirement

previously the maximum height allowed for attics is set as 5m as the previous regulations before envelope control allows for 2 storey houses to be built up to 14.1m and 3 storey houses up to 17.7m. the 5m max height for attic is to prevent owners from "over building" the attic as some owners may choose to do a reconstruction to add on an attic to the existing house.