Economics of Design

Question 1

Can you name some typical design ratios?

Answer 1

• Nett to gross
• Wall to floor
• Units per core
• Solid to Glaze
• Split between 1 2 and 3 bed apartment

Question 2

What are the typical design efficiencies and typical efficiency?

Answer 2

For Resi:
- NIA/GIA, 77%
- Wall to Floor 0.5:0.6
- Glass to Solid 40:60
- Units per Core 6 to 8
- Split between 1 bed 2 bed and 3 bed apartments. 50/35/15

Question 3

How would you improve your NIA/GIA?

Answer 3

• Make core spaces less
• Less internal partitioning and more open plan spaces
• Less roof terraces
• Steel frame over concrete
• Plant in ceiling voids or on the roof
• Make the building small and not reduce GIFA
• External staircases

Question 4

How would you improve your wall to floor?

Answer 4

• Simple shaped building
• No inset balconies or external wall recess
• Lower floor to ceiling height

Question 5

What would you consider when looking at glass / solid?

Answer 5

• Type of building use.
• Requirements for thermal performance, passivhaus requires more solid but does effect sales value.
• overheating issues

Question 6

Can you describe each RIBA stage?

Answer 6

• The current RIBA plan of works is the 2020 version. The stages are as follows:
• 0 – Strategic Definition
• 1 – Preparation and Brief
• 2 – Concept Design
• 3 – Spatial Co-ordination
• 4 – Technical Design
• 5 - Manufacturing and Construction
• 6 – Handover
• 7 – Use
• Stage 0-1 – Order of Cost Estimate
• Stages 2-4 – Formal Cost Plan 1 – 3
• Stage 4 – Pre-tender Estimate / Post-Tender Estimate

Question 7

Can you describe each RIBA stage?

Answer 7

The current RIBA plan of works is the 2020 version. The stages are as follows:
- 0 – Strategic Definition
- 1 – Interpretation and Brief
- 2 – Concept Design
- 3 – Spatial Co-ordination
- 4 – Technical Design
- 5 - Manufacturing and Construction
- 6 – Handover
- 7 – Use
- Stage 0-1 – Order of Cost Estimate
- Stages 2-4 – Formal Cost Plan 1 – 3
- Stage 4 – Pre-tender Estimate / Post-Tender Estimate

Question 8

How would you prepare an estimate for M&E works?

Answer 8

• I would ask an M&E specialist surveyor to undertake the estimate
• For feasibility estimates the M&E amount would be included in the m2/functional unit rate

Question 9

What is construction to ‘shell and core’?

Answer 9

• The basic structure, services and envelope of the building

Question 10

What is a CAT B fit out?

Answer 10

Partitions, power distributed to floor boxes, data cabling, artwork and branding, floor finishes on floor plates, joinery items

Question 11

What is a CAT A fit out?

Answer 11

Suspended ceiling tiles, raised floors, carpet, lighting, power distributed to floor plates

Question 12

Does your client want you to report the cost plan figures at tender date or at current price levels?

Answer 12

Most of my clients want to know the cost at tender, so including inflation

Question 13

What was the NIA : GIA on one of your projects?

Answer 13

78% on LTH

Question 14

What was the Wall : Floor on one of your projects?

Answer 14

0.63 - not particularly efficient, due to the inset balconies, offset floor, FFL to FFL height

Question 15

How does wall:floor impact cost?

Answer 15

The higher the wall area, typically there may be greater costs as it could mean a higher building, effecting the structure

Also, poor design efficiency leads to lesser returns for the client

Question 16

How did you advise the client that a ratio was poor?

Answer 16

Benchmarking against projects of a similar size/nature
Ratio analysis against other projects to understand where my projects buildings sat in comparison with other developments

Question 17

What is ratio analysis?

Answer 17

Looking at the key design efficiencies on a “dashboard” to show comparisons and benchmarking of these against other similar projects