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QS101 Residential Estimation

Miller_Kenneth_5069397 CQS101_AS1 Number of Pages?
Task 1 General concept of estimating
a) Explain what an SoQ is and the importance of preparing an estimate?
When preparing an estimate, it is very important to understand what it is, an estimate is
predominantly a rough calculation of the value of something, for example, to give an approximate
size, quantity, or value of something, as where an SoQ (Schedule of Quantities) is an exact size,
volume or value/cost of something.
There are different ways to give an estimate if someone is wanting an idea of the cost to build a
house and they know what size of the house they are wanting you can either give them an idea by
giving them a price per m² based on a historical house you have built with a similar specification or
by an m² from QV Costbuilder a program that provides an average cost range for residential and
commercial buildings. However, this cost will not be accurate but would give a fairly good idea at the
feasibility stage. The reason for this is a number of factors, type of roof material, bathroom fittings,
kitchen fittings, cladding type and very important is items like main services from building to public
connections, ground conditions these can vary considerably.
Then there is the elemental estimate, this is used when more information is provided such as floor
and elevation plans, beams, structural elements, and projections extruding further than the face of
the exterior walls such as columns, upper decks, external stairs, floor slabs or conservatories. An
elemental estimate is measured and priced, it is more accurate than the cost/m² method it could be
used for tendering for work but normally isn’t as the drawings don’t have enough information and
building consent has not been given.
As mentioned above an SoQ (Schedule of Quantities) is not really an estimate an SoQ is used to
price jobs as part of a tendered project it is the most accurate way of obtaining a price for a
construction project, it is a process of listing all the quantities of materials and tasks required for the
project headed under each trade summary, for example, all the materials quantities or task required
to carry, Site clearance Excavations, Foundations, would be headed under GROUNDWORKS. Internal
doors and frames would be headed under CARPENTRY, roofing and spouting headed under
A reinforced concrete slab would have the separate materials needed to lay a concrete slab such as
Hardfill, Sand, DPM, Reinforcing, Formwork and Concrete specified in their formula e.g., M, M², Mᶾ
There are 3 estimating methods.
1. Cost per m² method
2. Elemental Estimating (Preliminary estimate)
3. SoQ (Definitive Construction Estimate)
However, only SoQ (Schedule of Quantities) is used for tendering.
The SoQ (Schedule of Quantities) is more accurate than either a cost/m2 or an elemental estimate
because it is based on the most complete up-to-date set of drawings and specifications normally
used for the purpose of obtaining a tender bid.
b) What are the three methods available for sourcing rates for inclusion in an SoQ? Explain each
1. The first and only method to source a rate for inclusion in an SoQ (Schedule of Quantities)
would be by obtaining the Material cost, plant costs, Labour constant allowance for carrying
out the task, P&G rate, Overheads, and profit as seen below:
A carpenter’s labour hourly rate costs $48 per hour, he can install 3 internal doors in one
hour so 1 door takes 20 minutes or 0.33 hours per door to install. This would mean the
installation cost of 1 door would be $48 x 0.33 =$16 for the labour element of one door.
The material cost for each door would be $100. $48 x 0.33 + $100= $116 + preliminaries and
general (P&G) + overheads + profit] (if applicable)
As such the rate per door would be $116
2. Another way would be to get your rates put into an SoQ (Schedule of Quantities) is to get
the cost of the materials directly from the supplier and use that cost, plant costs, and any
other items needed for the project. Then there is the labour element working this out by
calculating the actual cost to the company for employing the individual and putting together
a program plan so the labour element can be costed accurately. Then there are the
overheads and profit which should be added to the actual cost of the labour element and
materials, this will then allow you to obtain your rate to put into your SoQ (Schedule of
3. Then there is what you call historical rates, these are based on projects carried out in the
past which are the same or very similar to the one you have been asked to provide an SoQ
(Schedule of Quantities) for, you can look at all the costs allowed for in that project and use
the same rates and if needed add an increase in the rates by a certain % depending on the
date you provided the SoQ (Schedule of Quantities) However, some people use QV rates,
unfortunately, depending on who you are they QV has a disclaimer on the rates and can not
be relied on.
C. What are the three common types of estimates? Explain the differences between them
The three most common types of estimates are:
1. Cost/m²
2. Elemental estimate
3. SoQ (schedule of quantities)
The differences between them are
1. A cost/m² is usually used at the feasibility stage when a client is wanting an approx. cost for
building a project, for example, a potential client wants a new house built but has no plans
or limited plans. However, they know the size of the house they want as such by defining the
total GFA (Gross Floor Area) you would multiply this by an approximate monetary figure for
example House size of 250 m² x $1500 = $ 375,000 cost.
2. An elemental estimate is a little better than a cost/m² as it there is now a proposed floor
plan with a design and a little more information than a cost/m². You have elevations,
sections, as well as floor details, be it one floor or two floors. Certain components are
grouped together based on their functions for instance:
1. Framing and its Function
2. Structural wall and its Function
3. Site works
4. Roof work
5. Interior walls
6. Interior doors
7. Fixtures & fittings
Elemental estimates are a very good way to provide a cost for building a property as each
element is actually measured and priced. However, generally, they are not used for the
purpose of a tender, as the drawings don’t have sufficient detail.
3. SoQ (schedule of quantities) is a list of all items required to build a property with the labour
costs, quantities from nails, screws, bolts, and all fixtures, to the finishing items such as
painting, carpets, and landscaping. These products will be listed under the main headings for
1. Painting
2. Carpentry
3. Windows
4. Groundworks
5. Masonry
6. Etc.
This is the SoQ (schedule of quantities) you would get under the heading #5 Masonry
1. As well as the benefits of an SoQ (schedule of quantities) at the tender stage it allows you to
use the information for future use
2. Helps in the certainty of progress payments
3. Used to compare contractors’ prices
4. Helps in the certainty of valuing variations
5. ‘Providing a schedule of quantities to tenderers will generate more interest
6. Provide a more accurate measure
7. SOQs (schedule of quantities) can often pick up on inconsistencies in the plans/drawings