Quantification and Costing of Construction Works Flashcards
What is a PC Sum?
- A Prime Cost Sum is an allowance included within the contract for works to be carried out by a nominated subcontractor or supplier, or a statutory authority.
- These costs may vary once the work has been carried out.
- The contractor is allowed to price allowances for attendance & OH&P
How would you price a provisional sum?
- Depends on the level of information available.
- use the drawings to ascertain any possible quantities & build up a rate based on the work involved.
- price any allowances for access.
- If a specialist piece of plant, possibly obtain a quotation for the item if there was sufficient information available.
- Include overheads & profit
What is a provisional sum?
- Sum of money included in the contract for work by a statutory authority, work that cannot be fully defined at time of tender or work that it is not sure is required
- 2 types, defined and undefined
What is a defined provisional sum?
- A sum included in the contract for work that has not been completely designed at time of time but for which certain specified information can be given
- Contractor deemed to have Made proper allowance for carrying out the work in their programme and preliminaries
- This means that they are not entitled to an EOT or extra prelims for carrying out the work, whatever the delay or cost of doing so to the contractor
- What if the actual work does not closely resemble the provisional sum?
Needs to be amended, treated as a CE
- What is an undefined provisional sum?
- A sum included for work for which there is minimal or no information at time of tender
- Contractor deemed to have not allowed for anything
- Not made proper allowance in programme or preliminaries for carrying out the works
- What are the risks associated with provisional sums?
- That the actual cost and time exceeds that allowed for in the provisional sum because the nature of the item changes between tender and instruction
- How can a provisional sum be expended?
PM issues instruction. Valued same way as a CE, by agreement.
What items would you include for when measuring for example a basement?
“It would depend on how the basement would be constructed. When measuring a basement with piled walls & assuming site was clear
1) Excavate & dispose of topsoil
2) Continuous piles to walls (including piling rig, hardstanding, testing, cutting & prep heads)
3) Excavate & disposal of arisings
4) Prep excavated surface
5) Waterproofing
6) Blinding
7) Concrete to basement slab & walls
8) Reinforcement
9) Formwork to walls
10) Finishes to concrete
11) Internal finishes”
When do you measure formwork to concrete?
Measured to the exposed faces of concrete requiring support during casting.
How do you measure cut and fill?
- Measuring software
- If software not available, obtain drawings with existing levels & proposed levels.
- divide the area of excavation into a grid
- interpolate the levels on the grid to establish an average existing & proposed level to determine which area was in cut and which area was in fill
Is the quantity for excavation similar as disposal?
Yes - providing there is no backfilling required. earthworks are to be calculated net from drawings, with no allowances for bulking, shrinkage or waste of earthworks
- What is BWIC?
BWIC stands for Builders Work In Connection and is usually set as a percentage of the services cost.
Depending on the size of the job and complexity will determine the percentage of BWIC.
BWIC accounts for any drilling, fixing, cutting etc… that the builders do whilst undertaking the services.
What is 200£/sqft in sqm’s?
I would have to consult the conversion tables contained at the back of spons
What items would you consider when carrying out a take-off for a piling operation?
- Piling rig,
- Hard Standing,
- Moving Piling Rig Between Piles
- Piles,
- Cutting & preparing heads,
- Pile caps (measured under concrete),
- Obstructions,
- Pile testing,
- Disposal of arisings.
