is classified in the list of priced items herein contained
and bid upon, the prices of which items include all
labor, material and expense of constructing the work
herein contemplated. If
(the Owner)
wishes other work done or the Contractor
wishes payment for doing work not so classified or in-
cluded, a separate contract shall be concluded be-
tween the parties to this end and no such extra work
shall be done or money paid therefor unless such con-
tract has been concluded, save that extra work done
by authority of
(the Owner)
writing may be performed under special agreement on
the basis of cost plus fifteen (15) per cent provided the
amount of extra expense involved under such agree-
ment shall not exceed one thousand dollars ($1000);
said cost to be proven by a Contractor's itemized bill
of labor and material verified by him under oath and
approved by the Engineer.

in

(the

(C) The Contractor shall do such extra work and furnish such material as may be required by Owner) ... for the proper completion or construction of the whole work herein contemplated; he shall make no claim for extra work unless it shall have been done in obedience to a written order from the Engineer, approved by (the Owner) All bills for extra work done in any month shall be filed in writing with the Engineer before the fifteenth of the following month; and said Contractor, if he fail to file such claims within the time required, shall forfeit all rights to payment for such extra work. The Contractor shall receive for such extra work the actual cost of all materials furnished by him as shown by his paid vouchers approved by the Engineer. For such labor and teams as are necessary for such extra work he shall receive the current prices in the locality, which shall have been previously agreed to in writing by the

Engineer and by the Contractor, and approved by plus fifteen (15) per

(the Owner)

"extra

cent. No additional work will be considered as
work" which in the opinion of the Engineer can be
properly included under the classifications of the

contract.

(D) The Contractor shall be paid for extra labor done by him and for extra materials furnished by him in compliance with written order of the Engineer, calling for work not similar in character to that covered by the items given in the proposal, and for which no price is set in said written order, their direct (not including consequential) cost to the Contractor, as determined by the Engineer to be reasonable, plus fifteen (15) per cent of said cost as so determined in regard to labor and six (6) per cent in regard to materials. The direct cost of labor may include the cost of mechanics and laborers furnished and a reasonable proportion of the time of the foreman and timekeeper. It may also include the cost of insurance on pay rolls where the total amount on any one order exceeds five hundred dollars ($500), but it shall in no case include any charge for the use of tools, for establishment charges or for time spent by the Contractor. The labor and materials so ordered shall constitute a part of the work to be done under the contract; and all and singular the provisions of the contract shall apply to said labor and materials as if the same were specified therein. The Contractor shall have no claim for compensation for extra work and materials unless the same are ordered in writing by the Engineer. The Contractor shall make daily with the Engineer a minute and detailed comparison in regard to men, rates, materials, prices, etc., and the agreement or disagreement as to each shall be carefully noted. He shall in addition, within one week after doing any labor or

furnishing any materials under an order given as afore-
said, deliver to the Engineer a copy of such order and
an itemized bill, in duplicate, based thereon. The
Contractor shall have no claim for the above named
extra work or materials unless he furnishes the details
and bills herein called for, and no other claim of the
Contractor against
(the Owner) ...... aris-
ing out of the execution of the contract shall be deemed
valid unless said claim is presented to the Engineer
within thirty (30) days from the time when he first
knows of or has opportunity to know of the acts and
circumstances on which the claim is based. A pay-
ment to the Contractor in cases where these pro-
visions or any of them are not complied with shall not
be construed as a waiver of such provisions or of any
part thereof.

57. Frequency and Amount of Partial Payments.

(a) One of the more important duties of the Engineer during construction is that connected with the payment to the Contractor of the money he has earned. On a small contract one payment made after the work is completed will often be satisfactory, but common practice is to pay the Contractor an installment each month (except in case of "progress payments"*) as the work advances. This enables the Contractor to carry on the work with a smaller capital than he would require if he had to wait for his money until the work was finished. The size of the installment is determined by the Engineer, and is based on the amount of work the Contractor has done during the preceding month.

(b) It does not represent the full value of such work, however, as a small percentage, commonly either 10, 15 or 20 per cent is retained until after the work is finally accepted, principally as a safeguard against defects which the Engineer may have overlooked and against bills for materials or labor which the Contractor may have neglected to pay. Additional security * How do these differ from monthly payments?

is furnished by the bond. (See Art. 11.) If the percentage is made very large it discriminates against Contractors of limited capital. Accusations of favoritism in respect to certain banks have been made in instances where the percentage held back has been unnecessarily large. If made too small it will not prevent a dishonest Contractor from abandoning the work immediately after he has received a payment on account. The retained percentage may be said to represent in a general way the Contractor's profit.

(c) The methods used by the Engineer in making up a partial payment account vary slightly, but are substantially as follows:

(i) With a unit price contract the process is comparatively simple, consisting merely in measuring the quantities of each class of work completed to date, and using these quantities, together with the unit prices in the contract, for computing the amount due the Contractor.

(ii) Under a lump sum contract the process is not quite so simple, as there are no unit prices on which to base the computation. In this event the Engineer must rely on his own judgment as to the value of the work done. (The Contractor might give him the computations on which he had based his bid, but of course he would be under no obligation to do so.)

The Engineer's Monthly Certificate (or Estimate), as it is called, is addressed sometimes to the Owner and sometimes to the Contractor. The phraseology would vary slightly according to circumstances, but the essential points to be covered are these:

(i) Recite the date of the contract and the full names and addresses of the principals thereto.

(ii) State the total value of the work done since the beginning of the

contract.

(iii) From this total deduct the proper percentage as provided in the specifications.

(iv) Sum up the payments on account to date, and subtract the total amount from the above remainder leaving a balance due at a date which should be named.

(v) Sign, date and number the Certificate. Engineers' Certificates should be made out in triplicate (at least), one copy for the Contractor,

one for the proper disbursing officer, and the third to be retained by the Engineer.

A troublesome question which sometimes arises in this connection relates to material which the Contractor has had delivered along the line of the work, but which is not yet in place. Shall the value of this material be included in any payments until the material is finally incorporated into the structure? Unless otherwise stipulated in the specifications at this point it would not be paid for until actually used, and it is doubtful if it is good practice to make any other arrangement in the specifications.* (See Art. 35.)

Typical Monthly Certificates

(I) (Assuming unit prices and addressed to the Contractor.)

I hereby certify that, in accordance with the terms of your contract with the Village of S..

sewer in X....

dated

..... "

.., for building a

St. you have to date done work and furnished materials to the several amounts and values named below, viz:

You are therefore entitled to a payment of the above balance on account on or before the 10th inst., in accordance with the terms of said contract.

* Discuss this point by making comparisons between the case of brick or cement furnished for paving, dressed stone furnished for a wall, fabricated steel furnished for a bridge or building.