Design economics Flashcards
What information is typically required for an OCE?
- Site information (Location, restrictions, use)
- Building information (Use, size, spec)
- Enabling works/decanting
- Programme
What are the methods of producing an OCE?
- Floor area method
- Functional unit method
- Elemental method
What is the elemental method of producing an OCE?
Using rates and quantities from other similar projects
What components make up an OCE?
- Measured works
- Prelims
- OH&P
- Fees
- Risks
- Inflation
How do you calculate Tender Inflation?
Inflation from the base date of your estimate to the date of tender receipt
How do you calculate Construction Inflation?
Inflation from the date of tender return to the midpoint of construction
Why is construction inflation taken to the programme midpoint?
This should account for inflation on materials procured throughout the programme, but may need to be amended if large items such as plant are procured towards the very start/end of the project
What are the types of cost plan?
- Stage 0: Rough OCE
- Stage 1: OCE
- Stage 2: Formal Cost Plan 1
- Stage 3: Formal Cost Plan 2
- Stage 4: Formal Cost Plan 3/Pre-Tender Estimate
Whats the difference between Whole Life Costing and Life Cycle Costing?
- LCC is cradle to grave
- WLC is LCC and other non-construction cost
What ratios can affect construction cost and why?
- Wall to floor (inefficient floor area using an expensive facade)
- NIA to GIA (wasted sellable space)
- Ceiling Height (Could be a waste of resources for no additional sellable space)
- Building height (the point at which deeper foundations are needed can make the build inefficient)
- Shape regularity (linked to wall to floor)
What sources of cost data are there?
- Benchmarking
- BCIS
- SPONS
- Market testing
What are pros and cons of Benchmarking?
Pros
- Can be used for specific rates
- Provides a wide variety to give an average
Cons
- Need to take into account inflation and location factors
- Need to understand nuances to see if the data is applicable to your project
What is a fair net to gross?
70-80%
Whats a good wall to floor ratio?
0.4-0.5
What’s the difference between cost and price?
- Cost is Labour, Plant, and Materials
- Price is what the Client pays, and it includes the Cost and OH&P
How do you proceed if your cost plan exceeds the budget?
- Check your assumptions to see how well they align with the designers’ intentions
- Look at the reason for the overspend i.e. if the budget was based on another project, what makes this project different?
- Look at potential value engineering solutions
What is buildability?
A review during the design stage of how the components and will be manufactured and put together. Typically, this can be improved through early contractor involvement
What is shell and core?
The main structure, basic services, and external shell of a building. It might also include fitting out common areas like a reception, with services leading to but stopping at tenant thresholds. Life safety equipment will typically be installed throughout however
What is Cat A?
This is a fit out of basic finished such as ceiling tiles, Raised Access Flooring, carpets, and basic lighting and power
What is Cat B?
This is full fit out with bespoke elements, internal walls, upgraded finishes, services feeding into floor boxes
What is BWIC?
Builders Work in Connection. This is typically to take into account works such as drilling, fixing, cutting etc when they’re installing the services
What are preliminaries?
Costs for items that are necessary for the Contractor to complete the works, but are not the works themselves
What is typically excluded from a cost estimate?
- VAT
- Fees
- Site acquisition
- Section 106/CIL
- Asbestos removal
- Loose FF&E (Desks etc.)
What is RIBA Stage 0?
Strategic Definition
