The evaluation of a quotation is in itself an "art"
and in principle only reserved for skilled and experienced engineers or
architects. The "art" is to find the hidden loopholes in a quotation and
the comparison of "apples to apples". However, no need to be an expert
if you wish to evaluate a quotation for a Timber Prefab House, as in
fact this is a straightforward exercise if you follow the tricks, tips
and hints given below.
Assume that you have inquired for a quotation from 3
different manufacturers, either based on their standard models or based
on a drawing made by yourself or your architect. Before you start you
need to define the weigh factors, i.e. what is most important to you.
Example: You will build the house in a cyclone area. Most important is
that the house will remain in tact during a cyclone (at least for the
greatest part). You may give this a weigh factor of 1. Other important
factors may be that the house shall have termite resistant timber, a
coating system with a guarantee of at least 3 years, stainless steel
fixtures, double sidings, roof decking, low floor deflections, no nails
used, the durability, the price, the payment system, lead time and many
more. Each of them shall be given your own importance weigh factor. In
conclusion, before you start an evaluation you need to prepare a list
with items followed by a weigh factor for each of the items plus a list
of your requirements. The next step is that you obtain specifications
from the supplier (what we have already done for you on our
With the specifications in hand from the 3 suppliers you start your
evaluation. Each and every part of the quotation that does not fit or
match your requirement shall be given a lower weigh factor. Example: You
wish double siding boards with a minimum thickness of 25 mm each. Your
chose a weigh factor to this requirement of 0.7. One of the quotations
proposes single board sidings of 25 mm thick. You may give this a weigh
factor of say 0.5. The second supplier proposes double board sidings
with a thickness of 16 mm. You may give this a weigh factor of 0.55. The
third supplier complies with your requirement and proposes double siding
boards with a thickness of 25 mm each. The weigh factor shall be 0.7.
You repeat this for all the items and summarize the weigh factor for
each supplier. Now comes the trick to know which of the suppliers has
submitted the most responsive bid (hence most advantages for you).
This part of the evaluation comprises two aspects, viz; the price and
the technical compliance (weigh factors). Step 1: Divide a figure of 100
by the summarized weigh factors. Step 2: Divide the price that each
supplier submitted by the resulting figure from the previous
calculation. The highest score is the supplier who submitted the most
Supplier 1: Summarized weigh factor is 14.85. Their price is USD.
Supplier 2: Summarized weigh factor is 12.35. Their price is USD.
Supplier 1: Summarized weigh factor is 17.65. Their price is USD.
Score of supplier 1: 100/14.85 = 6.734 Price/quality ratio is
75,000/6.734 = 11,138
Score of supplier 2: 100/12.35 = 8.097 Price/quality ratio is
68,000/8.097 = 8,398
Score of supplier 3: 100/17.65 = 5.665 Price/quality ratio is
83,000/5.665 = 14,651
The obvious winner is supplier 3, despite its higher price. Though the
calculation is merely based on axioms and arbitrary parameters it will
give you at least a good insight in the responsiveness of a bid.
The above is a very simple example of how it actually
works in the world of construction, be it that large projects (in the
millions of Dollars) do have much more complex weigh factor systems
which also includes the number, skill and experience of the employees
working for the supplier, project references, financial statements,
presentation of the quotation, guarantees, lead times, etc.
To help you with a simple weigh factor system (by far
complete), refer to the table below (this is just an example. P.T. Bali
Woodworld will not accept any responsibility in the case of errors, or
otherwise). A very good weigh factor table may contain over 50
||Minimum non-compliance weigh factor
|House shall be cyclone resistant
|Timber closest to natural grade shall be
|All fixtures shall be stainless steel
|Sidings shall be double boarded
|Coating shall be guaranteed for 3 years
|Siding board thickness shall be minimum 25
|House shall be elevated from natural grade
|Floor deflection shall not be larger than
1/600 x span
|Truss deflection shall no be larger than
1/400 x span
|Structure shall comply with the local
building authority regulations
|Timber for boards shall not exceed 15%
|No nails shall be used
|All wood connections shall be T&G
|Large glass areas for doors and/or windows
shall be safety glass
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