Composite Rate Build up – Floor Construction
In this example, the Elemental Estimate layout and grouping of items will be used. There are principles that you have to follow when building up composite rates for Approximate Quantities. We are going to illustrate a composite rate buildup for Ground Floor Construction:
Topsoil excavation average depth 150mm, 100mm surface concrete bed (30MPa) on DPM, on 25mm thick sand blinding under floors, over 150mm hardcore filling on compacted ground including ant proofing and mesh wire reinforcement.
Step 1
First, you have to determine the Group unit of measurement. When you are measuring Ground Floor Construction in Elemental or Approximate Quantities estimating, the group unit of measurement is the square metre (m2).
Step 2
The second step is listing all associated Bill items that can be mapped to Floor Construction by area. These are:
 Topsoil excavation – (m2) Rate – 5.00
 Surface concrete bed – (m3) Rate – 1200
 Mesh wire reinforcement – (m2) Rate – 125.00
 DPM – (m2) Rate – 7.00
 Sand blinding under floors – (m2) Rate – 35.00
 Hardcore filling – (m3) Rate – 40
 Ground compaction – (m2) Rate – 5.00
 Ant proofing – (m2) Rate – 7.00
 Striking off and floating top surface – (m2) Rate – R10
 Ceramic floor tiles – (m2) Rate – R250
 Screeds – (m2) Rate – R30
Step 3
Since your Group unit is the square metre (m2), you should convert the Bill item rates to Cost per Square Metre.
Rate Build Up
GROUP – GROUND FLOOR CONSTRUCTION 
Rate – Cost Per Square Metre (m2) Rands  
1m2 of Topsoil excavation  
1m2 = R5.00  5  
1m2 of Surface Concrete Bed  
100 x 1000 x 1000  
0.10 x 1 x 1 = 0.10m3  
0.10m3 x 1200 = R120  120  
1m2 of Wire Reinforcement  
1m2 = R125  125  
1m2 of DPM  
1m2 = R7.00  7  
1m2 of Sand Blinding  
1m2 = R35  35  
1m2 of Hardcore Filling  
150 x 1000 x 1000  
0.15 x 1 x 1 = 0.15m3  
0.15m3 x R40 = R6.00  6  
1m2 of Ground Compaction  
1m2 = R5.00  5  
1m2 of Ant Proofing  
1m2 = R7.00  7  
1m2 Striking off and floating  
1m2 = R10  10  320 
1m2 Ceramic floor tiles  
1m2 = R250  250  
1m2 Screeds  
1m2 = R30  30  280 
Composite Rate – GROUND FLOOR CONSTRUCTION  600 
The composite rate for GROUND FLOOR CONSTRUCTION is R600 per square metre.
Elemental Layout and Grouping
Items which go into the element GROUND FLOOR CONSTRUCTION and component Solid Floors are stated in the description:

Unit  Quantity  Unit Rate  Cost/m2  Subtotal  Cost  
GROUND FLOOR CONSTRUCTION


Solid Floors:


100mm Mass concrete surface bed on USB Green DPM on sand bed, over hardcore filling on prepared ground, including ant proofing and mesh wire reinforcement.  M2  320  
Subtotal
GROUND FLOOR CONSTRUCTION 
M2 
Items which go into the element FLOOR FINISHES and component Applied Floor Finishes are stated in the description:

Unit  Quantity  Unit Rate  Cost/m2  Subtotal  Cost  
FLOOR FINISHES


Applied Floor Finishes:


Allow a PC Sum of R150/m2 for Ceramic floor tiles fixed with adhesive on/and including 25mm screed.  M2  280  
Subtotal
FLOOR FINISHES 
M2 