hints on supervision of works

8/2/2019 Hints on Supervision of Works

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HINTS ON SUPERVISION OF WORKS

I GENERAL

a) Study carefu lly al l drawings, specif ications and contract condit ions.Without a thorough knowledge of these you cannot possibly supervise the workeffectively.

b) Make notes of salient features of the contract and keep it as a readyreference.

c) Ensure that the Site Instruction Book is always available at si te and allimportant events are entered in it , when there is more than one engineer at site,the s ite ins truc tion book should p referab ly be s igned by the des ignatedengineer(s) only.

d) Ensure that t he contractor s work i s properly organized a nd t here areadequate arrangements for off ice, storage, water supply and electric supply etc.Do not interfere with the contractor s organizat ion unless you have a def in i teplan for its improvement.

e) Do not be a spectator at si te. Correct faults as soon as you see them.You can effectively contribute to raising the standards of work by making eachtradesman do a small sample of h is work under your c lose supervision. Insiston all his work being upto the standard of his sample.

f) Extend the above concept and complete a sample unit as early as

possible.

g) Reject a l l bad work as soon as i t i s noticed and insist on i ts beingimmediate ly d ismant led or rect i f ied. I f the contractor fa i ls or cannot rect i fyimmediate ly fo l low the procedure and ra ise a Non Conformance Report . Youshould also make an entry in the si te instruct ion book and get i t s igned by thecontractor. Bring such defects to the notice of the Inspecting Off icers.

h) Ensure that tools and instruments for checking and supervision of worksare readily avai lable at s i te and use them constant ly. Avoid checking of smal lmeasurements with measuring tape.

i) Supervise work on a dai ly basis but do not have a f ixed routine. Varyyour routine both with reference to t ime and items of work checked.

j) Do not al low inadequate or dangerous scaffolding and obs erve al l safetynorms even if enforcing safety is not in the PMCs scope of work.

k) Complete the construction si te dai ly report, document no. EXPF-RT0411with re levant informat ion of contractor s labour, mater ia l , weather condit ions,progress of work hindrances and other relevant information.


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l ) Ensure p roper co-ordination b etween various t rades such as concreteand masonry work on the one hand and water proof ing, p lumbing, san i tary

works and internal electrif ication on the other.

m) Ensure that al l materials required to be incorporated in the work are dulytes ted w ith reference to IS, con trac t speci fi cat ions and approved by theCompetent Author i ty . Frequent and random checks must be carr ied out toensure that only approved material is used.

II SETTING OUT

a) Ensure you have a proper foundation plan before set ting out.

b) Verify the orientation and set out the center l ines on the ground.

c) Verify t hat t here a re no services such as water mains, sewer l ines,drains, cables etc. interfering with the layout.

d) Use only a standard steel tape for al l measurements in connection withsett ing out . Dr ive in wooden pegs, c lear o f the foundation l ine and on theextension of centre l ines.

e) The top of the peg should be left a l i t t le above the proposed pl inth level.Mark the extension of the centre l ine exactly on these pegs and drive in nails tomark the al ignment with the head of the nai l project ing about 15mm above thepeg.

f) Recheck all d imensions and right angles. Right angles should beche cked b y t ak in g t ap e mea su re me nts i n t he rat io o f 3 :4 a lo ng t he twoperpendicular sides. The third side (should measure should measure f ive units.

g) Build up masonry pil lars around the pegs and f inish with cement plaster to match exactly with the plinth level.

h) You can now correctly set out foundations trenches and check allal ignments and plinth levels from these markers.

II I FOUNDATION

a) Insist on al l excavated material being kept at least 1m away from thetrenches.

b) Check the base o f the foundation t rench for sof t spots or cavit ies. I f necessary have these dug out and ref i l led.

c) Refi l l ing upto p linth level must be done in layers o f 15 cms and wel lwatered and rammed.


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d) The concrete should be laid in layers not more than 15 cms thick whenwithout v ibrat ion and not more than 30 cms th ick with v ibrat ion. As a guide

check l ines can be snapped along the sides of the t rench indicat ing requiredthickness.

IV BRICK WORK

a) Ensure that the correct bond as specif ied is used. Do not al low bricks of dif ferent sizes in the same work.

b) Do not al low brick bats except where closers are required.

c) Ensure that the bricks are well soaked before use.

d) Check frequently for

i . Thi ckne ss of ma so nryi i . Vert ical i ty a long the sides as wel l as cornersi i i . Horizontal coursesiv. Breaking of jo ints andv . Thickness o f jo in ts .

e) See that joints are properly f i l led. Masons prefer to lay bricks dry and f i l lmortar from the top. Do not al low this.

f) Ensure that holdfast and holding down bars are as specif ied and treatedwith p rese rva tive. As fa r as poss ib le have these ins ta lled in your p resence and ensure they a re p roperly sur rounded w ith mor ta r o r concrete as specif ied.

g) Check sizes of al l rooms as soon as the works start on super structure.

h ) Masonry works above eye leve l i s general l y no t superv ised bu t i t i sessential to do so. Insist on ladders and good scaffolding being providedto inspect the masonry.

i ) Work should general l y p roceed at one leve l when for any reason i t

becomes necessary to leave any port ion of work, see that the masonry isstepped back and not merely toothed.

j) Mas ons ar e ge neral ly car eless about making sides of doors and windowstruly vert ical. Check these frequently as work goes up. Also ensure thatl intels are horizontal and provided with adequate bearing.

The above apply generally to Block work also


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V STONE MASONRY

Apart from common points covered above in br ick work, fol lowing pointsneed to be kept in mind.

a) Avoid laminated stone and e nsure that the stone used is t he bestava i lable and as speci f ied . The tendency to prov ide good fac ing s tone andfi l l ing the heart ing with small pieces and rubbish should be avoided. The idealto be aimed is a maximum of large stone and a minimum of a mortar.

b) Check all bond stones are in correct posit ion and they are marked withpaint at both ends. Uncover stone so marked at random to conf irm that they

are infact bond stones.

c) Checking for vert ical ity in stone masonry is even more important due toirregular size and shape.

VI PLAIN AND REINFORCED CONCRETE

a) Before concreting ensure that labour, material approaches, walk waysare properly organized.

b) Keep a constant check on the water content and never permit addit ion of water after mixing is completed.

c) For site mixed concrete without any admixture, it is a safe ru le to placeall concrete with proper compaction within 30 minutes after adding water to themix. Do not al low further ramming or reworking after the init ial set of cement.

d) At the close of a days work any unfinished concrete should be steppedand joint preferably covered with damp Hessian / gunny bags.

e) Avoid concreting under adverse condit ions i.e. either wet or too cold or too hot. Where unavoidable ensure al l precaut ions and procedures are str ict lyfol lowed

f) Ensure continuous and proper curing and do not remove forms unti l theconcrete has hardened.

g) Al l re inforcement bars should be cleaned and free from scales, oil ,grease etc.,

h) Placement of reinforcement should be checked for spacing, diameter, laplength, tying up, dimension of hooks and bends & cover.


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i) Al l concrete should be adequately compacted by vibration using thecorrect type and size of vibrator and correct procedure

VII JOINERY

a) Check that the t imber used is of specif ied species and c lass and ismatured and seasoned.

b) Joints in wood work should be properly made. This is extremelyimportant as very few carpenters employed at sites are really skil led tradesman.

c) Open and close al l doors and windows and check hinges and screws.S imilar l y check a ll hardware f it tings for cor rect pos it ioning and ease o f operation. Hardware should a lso be checked for d imension and weight asspecif ied.

VIII AC SHEET ROOFIN G

Str ict ly fo l low the code of practice issued by sheet manufacturer. Thiswil l g ive you the number and pos it ion o f hook bol ts and the cor rec tmethod of f ixing and f it t ing of AC sheet and use of bitumen washers. ACsheets should not be bolted down too t ightly. This wil l lead to breakageswhen the sheets expand in hot weather.

IX PAINTING AND GLAZING

a) Ensure that the surface is thoroughly clean and stopped before

appl icat ion of pr ime coat. Cleaning should a lso be done before applicat ion of subsequent coats. Do not a l low use of rags, cot ton waste, damaged brushesfor painting.

b) Do not al low painting to be done on damp surface. When ready mix paintis used ensure that sealed containers are brought to s i te and opened in yourpresence. Paint should be well st irred before and during use.

c) See that the top and bottom edges of joinery are also painted.

d) In fixing glazing ensure the use of back putty so that the panes si t f irmlyand do not ratt le.

e) Check weight of glass.

X PLASTERING AND POINTING


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a) See that al l joints are thoroughly raked out before work commences. If joint s are not struck as the work progr ess, insist on joint being raked out everyevening as otherwise mortar wi l l set and subsequent ly raking out wi l l be not

only dif f icult but wil l also damage the edges of the bricks.

b) The joints should be washed and well wetted before commencing of work.

c) In plastering see that laths (bull marks) are used to mark thickness of coat required. Laths should not be more than 1.5m apart.

d) In two coat work the first coat should not exceed the specif ied thicknessand should be kept wet for 7 days before second coat is applied.

e) Ensure that plastering is even and in plane. Al l precautions should betaken to ensue proper grading of sand, mixing of mortar and curing af ter the

work is completed.

XI SANITARY FITTINGS

a) Check that sanitary f i tt ings are fixed at correct heights and in the correctposit ion.

b) Before f ixing ensure t hat f i t t ings a re f ree f rom f laws such as cracks,dents and distort ions and the glazing is uniform.

c) On instal lat ion al l fi tt ings should be checked for proper functioning.

XII SEWERAGE

a) Ensure that the alignment, width and depth of the excavations for pipesand manholes are correctly maintained.

b) Al l pipes should be free from cracks and SWG pipes should be uniformlyglazed. Every l ine and manhole should be tested before covering with earth.

c) Manholes should be provided at proper intervals and the f loor of themanhole should have proper benching to ensure smooth f low.

XII I INTERNAL ELECTRIFICATION AND WATER SUPPLY

a) Layout diagram for internal wiring, pipe l ines showing location of f i t t ingsand f ixtures should be prepared and got approved before commencementof work.

b) Holes, chases e tc made in the st ructure shou ld be f i lled properly andmade good to match the surrounding.

c) All work must be thoroughly tested before acceptance.


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d) In approving materia l for e lectr i f icat ion, the fo l lowing points should benoted.

I . The make of the i tem should be one of those given in contract .

i i . The sources of purchase should be an authorized or reputeddealer.

i i i . The items brought to si te should be new and not used.

iv. The finish of the items should be to accepted standards.

v The physical dimension, gauge, weight etc, should be as specif ied.

e) Batten used should be well seasoned of Teak wood and not sap wood.

f) I t is preferable to mount a l l approved samples on a board and display atsite for easy reference.

g ) A ll e lec tr ical work should be ca rr ied out only by l i censed e lect ri calcontractor.

h) The posi t ion o f switches and f i t t ings a t s i te shou ld be marked and gotapproved.

i) Wooden gutt ies should be avoided and instead, fasteners or screws driven

into good quality plastic plugs used. I f gutt ies are provided they should notbe more than 75 cm apart and insta l led with the large end inside and thesmall end f lush with the f inished wall or ceil i ng.

j) All wiring runs should be ei ther vert ical or horizontal . Do not al low diagonalruns.

k) Al l service wir ing with in 1.5m from the f loor should be protected by pipe /conduit.

l) Ensure that the correct capacity of MCB and fuses are used.

m) Switch boxes and boards should be clean and without any t race of deadmortar, cut pieces of wires, screws and washers etc., inside them.

n) Light and power points should be on separate circuits.

o) I t is preferable to l imit the maximum load on each l ine circui t to 800 wattwith a maximum of 10 points. Similarly there should not be more than twopower socket points per c ircui t and the load should not exceed 15 Ampsgenerally.


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p) Ensure correct s ize and mater ial o f cable and do not a l low jo in ts in thewires.

q) Do not permit cutt ing off of few strands to make end connection in case ofstranded cables / wires.

r) Ensure that short length of wire is left as spare at each switch board box.

s) Ensure that conduits are enamel painted both inside and outside.Conduits of correct size should be laid in walls before plastering.

t ) Ensure pipe hooks or saddles for f ix ing conduits in chases are provided(general ly at 60 cms spacing) and are also provided with in 10 cms of af it t ing.

u) Keep all open ends plugged t i l l the drawing of wires.

v) Posit ion junction box judiciously. Junction box cover should be f lush withf inished surface of wall / ceil ing.

w) Avoid sharp corners and bends in surface bat ten wiring. Use smoothcurved wooden blocks at such places.

x) Ensure that switches are not on the neutral l ine.

y) Ensure proper maintaining height above f inished f loor level for al l f i t t ings.

General guidelines are given below:

i. Bracket l ight points : 215cmii. Fan regulators : 100/120cmiii . Socket outlets with switches 100/120cmiv. Power socket out lets in k i tchen 30cm above countertopv. Bel l buzzer : 215cm

Bathroom bracket l ight 200cm and over mirror centre

vi . Bathroom shaving socke t 115cms and 2 0 cms away from mirr or edge.

vi i. Geyser socket : 215cm

vi ii . Geyser switch : 100/120cm

z) Do not use water pipes as earth and ensure that l ight circui t and powercircuit each has an independent earth.

aa) Ensure proper earth wire continuity and resistance. On completioncheck each circuit for continuity and polarity and carry out the fol lowing tests.

i. Insulation resistance test


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i i Earth continuityi i i . Earth resistance testiv. Polarity test

a b) On complet io n, d etai l wi ri ng diagram sho uld be p re pared f or record. Thi sshould show main switch board details, runs of various main and sub mains andposit ion of al l points circuits.

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