Design Economics and Cost Planning Flashcards
What is an order of cost estimate?
- The determination of possible cost of a building(s) early in design stage in relation to the employer’s fundamental requirements.
- Prior to preparation of a full set of working drawings
What is an elemental cost plan
- the critical breakdown of the cost limit for the building(s) into cost targets for each element of the building(s)
What are the key design principles that affect cost?
- Circulation space
- Size
- Shape
- Height
- Wall to floor ratio
- Grouping of buildings
- Specification
- Location
How does wall to floor ratio impact the cost of a building?
If the building has a lot of facade covering little area, the cost/m2 for the building would be high.
The cost for the high quantity + therefore cost of the facade is being divided over a small area.
How does size impact the cost of a building?
A bigger building will have economies of scale, reducing the price subject to the size being designed efficiently
How does circulation space affect the cost of a building?
The “cost”/m2 in relation to net area will be higher if the “cost” is carrying surplus non-lettable circulation space.
Too little circulation space however, will make a building unattractive to a tenant reducing the rent/sales value for the client
How does the height of a building affect the cost?
A tall building may require more lift cores, reducing net space on each floor plate.
Bigger foundations, beams etc required
Requirements for better facades to deal with greater wind loads and sprinkler requirements for buildings over 30m high (approved doc B)
How does the shape of a building affect the cost?
Curved shapes are expensive to manufacture + construct due to complexity
Inefficient shape could cause high wall to floor ratio
Most efficient shape is a square (excl circle because of curve)
How does the grouping of buildings affect the cost?
Less facade per m2
Ability to share plant etc
What’s a good, average and poor W:F ratio?
Good = 0.4
Average = 0.6
Poor = 0.8
What percentage of a construction cost would you expect for facades?
15% - 25%
What net to gross would you expect for an office?
Good - 80% - 83%
Excellent - 83% - 86%
Poor - over 87% or under 80%
What government guidance document discusses school areas?
Building Bulletin 103: Area guidelines for mainstream schools
What net to gross would you expect for a school?
70% - 75%
What is net vs non-net for schools?
Non-net = WCs, personal care, circulation, kitchen, plant, internal walls
Net = everything else, incl learning, storage, halls, staff space
What was the GIA for the school you worked on?
Phase 1 - 2024m2
Phase 2 - 7500m2
What was the net:gross?
72%
What are the full names for NRM1 and NRM2?
New Rules of Measurement 1: Order of cost estimating and cost planning for capital building works
New Rules of Measurement 2: Detailed measurement for building works
How is NRM1 structured?
1 - Context & definitions
2 - Rules for preparing OCE, how to quantify non-measurable works
3- Rules for cost planning, how to quantify non-measurable works
4 - Tabulated rules of measurement
Appendices
How is NRM2 structured?
1 - Context & definitions
2 - Rules for preparing Bill of Quants, Schedule of Rates, how to quantify non-measurable works such as risk, contractors design works
3 - Tabulated rules of measurement
Appendices
What’s the difference between a cost estimate and a cost plan?
Cost estimate gives a likely outturn of construction costs
Cost plan is an iterative process, updated and tracked as design progresses, to control the development of the design and ensure the client achieves value
What is a cost model?
Anything that models costs, e.g. cost plan, estimate, analysis
What’s benchmarking and how would you benchmark a project or element?
The process of collecting and comparing data within an organisation or external
to an organisation to identify the ‘best in class’
- Collect
- Compare
- Analyse
- Action
- Repeat
What’s the relationship between the RICS Property Measurement 2nd Edition, RICS Code of Measuring Practice 6th Edition and IPMS?
RICS Property Measurement 2nd Edition 2018 - This is a Professional Statement, states what we should use and when. Office and Residential = use IPMS.
Code of Measuring Practice 6th Edition 2015 = Guidance Note, how to measure GIA, NIA, GEA
IPMS - how to measure IMPS1, IMPS2, IMPS3 for offices, resi, industrial and now retail.