Estimating & Tendering

Estimating work involves dealing with Measurements and quantities Pricing and rates Subcontract packages Tender preparation

Types of contract -Lump Sum or Hard Money contracts -Cost plus %-age contracts -Cost plus fixed fee contracts

TERMINOLOGY Provisional Cost sum, is a cost to supply and fix an item Prime cost item, is the price for supply only

Example 1 A $ PC sum was allowed for A/C in the contract. The actual cost ended up being $8 500, so the client gets a $1 500 refund. Example 2 A $ PC sum was allowed in the contract. Actual cost was $ Charge the client the extra $1 500 plus your margin of say 10-%, a total of $ Example 3 $35/m2 for a 100 m2 tiled floor was allowed in the contract. If the tiles the client chose cost $30/m2, the client gets a refund of $5/m2 x 100 m2 = $500.

More Terminology Client Contingencies: This is an amount set into the contract to cover an unknown amount of work. Say you allow $ for excavating through rock. At the completion of the contract the contractor must accurately account for the actual costs and offset it against the allowance made. Contractor Contingencies: Contractors can use contingency allowance for unknown events that they are contractually bound for. In this instance it covers the contractors risk and can be a %-age on the contract value and dependant on how risky you think the job is. If the contingency is not used, it is not returned to the client but increases the contractor’s profit.

Factors to consider when tendering -How much work have you already got on? Do you want or need more work? -Can you handle more work and is it going to be profitable? -Are you technically and financially capable? -Who is the client or Architect? Good to work with? -How many tenderers are there likely to be? -Who is the main competition? Are they desperate for work? -What are your chances of success?

EARTHWORKS Demolition? Clearing and levelling the site Setting out new buildings Excavating for footings

Minor demolition example Estimate: Machine hire: 20 $60/hr = $1 200 Labour: 1 person 20 $25/hr = $500 Truck hire: 15 $50/hr = $750 Dumping fees: 85 $8/ton = $680 Total = $3 130

Terminology A Foundation is the prepared soil that you are going to start building on A Footing is usually made from reinforced concrete and is the first thing you build upon that foundation

ESTIMATING SHEET Project:Estimator: Location:Extended Date:Sheet No. of Form 1/A DescriptionUnitQuantityRateEstimate

Example – raft slab footing 5 x 5 m in plan with 500 x 300 mm beams around the perimeter and a 100 mm thick slab. Edge rebate for brickwork

TRENCHING incl edge form Description Unit Qty Rate $ Setting out: 1 person ½ day hr Backhoe 1 day hr Clear site to 150 mm m Labour: 2 persons 1 day hr Spoil removal 6.8 m3 ton Total to summary $1 786

CONCRETE placement and finishing Description Unit Qty Rate $ Labour 2 persons 1 day hr Concrete pump* No Vibrator (own) No Miscellaneous 100 Total to summary $930 Due to limited site access Concrete supply m $720

Quantity of concrete (Use centre lines to measure) 5000 mm 5000 – 2 x 60 = – 2 x 150 = – 2 x 300 = – 2 x 350 = Slab: 4.4 x 4.4 x 0.1 = 1.94 m3 Beam: 0.3 x 0.5 x 4.7 x 4 = 2.82 m3 Wedge: 0.15 x 0.15 x 0.5 x 4.3 x 4 = 0.19 m3 Rebate: x x 4.88 x 4 = m m3 Add 20% 0.95 m3 5.7 m Say 6 m3

REINFORCING Description Unit Qty Rate $ Reo bars 6 Y16 20 lm x % lap/waste lm Ligatures pre-fab 0.6 m cts. 20/ % No Fabric F72 to slab 5 x 5 = 25m2 + 20% laps m Chairs and ties item DPM 100 x 2 m roll No Total to summary $810 Labour 2 persons 1 day hr $480

SUMMARY Labour Trenching $1 786 Reo $480 Concrete $930 Material Reo $810 Concrete $720 Total $4 726

Example – Carpentry Say we have a four walled room 5 x 5 m with 2.7 m high walls. All timber is 70 x 35 pine with studs at 600 mm c/c. Description Unit Qty Rate $ 70x35 top and bottom plates lm x35 studs lm x35 noggins lm Damp Proof Course roll No Nails and Dynabolts item 20 First fix carpenters 2p x 2 day hr Miscellaneous 100 Total to summary $1 691

How many bricks per square metre of wall? Standard brick size 230 x 76 mm Mortar joints nominally 10 mm Area taken up by one brick is x = m2 We get 1/ = bricks/m2 For small areas round off to 50/m2 and add a %-age for waste

Tendering process -Ensuring that you are invited to tender, if that is limited -Taking the tender documents, which consist of drawing, specifications and sometimes a bill of quantities, and breaking them down into packages. These packages must be appropriate for your subcontractors to bid for. -Inviting subcontractors to bid and evaluating the bids. -Adding up all construction costs plus the preliminaries or overheads plus your margin to form the tender price. -Finally, you need to submit the tender as per the instructions, and don’t be late!