FLOOR AND WALL FINISHES

 

16.1     Scope of Work

The Work under this Section of the Specification consists of furnishing all plant, labour, equipment, appliances and materials and performing all operations in connection with the installation of cement concrete floors and floor finishes including bases, skirting and Dado, complete in strict accordance with this Section of the Specification and the applicable Drawings.

16.2     Applicable Standards

Latest editions of following Pakistan, ISO, British & ASTM Standards are relevant to these Specifications wherever applicable.

16.2.1  Pakistan Standards

P.S. 232 Ordinary Portland cement

16.2.2  ISO (International Organization for Standardization)

R 680	Chemical analysis of cements Main constituents of Portland cement
FR 681	Chemical analysis of cements Minor constituents of Portland cement

16.2.3  ASTM (American Society for Testing and Materials)

C 482	Bond strength of ceramic tile to Portland cement
C 648	Breaking strength of ceramic tile
C 650	Resistance of ceramic tile to chemical substances
C 798	Colour permanency of glazed ceramic tile
E 84	Surface burning characteristics of building material

           

16.2.4    BSI (British Standards Institutions)

882 Pt.2	Course and fine aggregates from natural sources
1199	Sands for external renderings, internal plastering with lime and Portland cement and floor screeds
1201 Pt.2	Aggregates for granulithic concrete floor finishes
1281	Glazed ceramic tiles and tile fittings for internal walls
5442	Classification of adhesives used Construction Pt-1 Adhesives
203	Tile flooring
204	In-situ Floor Finishes
209 Pt.1	Care and Maintenance of floor surface, wooden flooring

           

16.3     Material

16.3.1  Cement

Cement shall be ordinary Portland cement conforming to BS 12 or PS 232.

16.3.2  Sand

All fine sand shall be as specified or approved by the Engineer and stored on properly constructed paving or as directed by the Engineer. The grading shall conform to BS 882 Grading Zone 1 and 2 of which the gradation limits are as follows:

Percentage (by weight) passing
BS Sieve	Grading Zone 1	Grading Zone 2
3/8” (9.53mm)	100
3/16’ (4.765mm)	90 – 100	90 – 100
No. 7	60 –   95	75 –   90
No. 14	30 –   70	55 –   90
No. 25	15 –   34	35 –   59
No. 52	5 –   20	8 –   30
No. 100	0 –   10	0 –   10

16.3.3  Coarse Aggregates

(i)         Coarse aggregate shall be obtained from approved source fully crushed, angular in shape and shall have granular, crystalline and broken surface free from friable, flaky and laminated pieces, mica and shale. It shall not contain matters injurious to concrete. All coarse aggregates shall conform to BSS NO.882 and shall be graded as follows:

BS Sieve	% Passing by weight
1”         (25.40 mm)	100
3/4”      (19.05 mm)	90 – 100
3/8’      (9.53 mm)	20 –   55
3/16’    (4.765 mm)	0 –   10

           

(ii)        The aggregate shall be stored on properly constructed paving or as directed by the Engineer.

(iii)       There shall be a physical partition between the stockpiles of coarse and fine aggregate. If required, aggregates shall be washed and screened to the satisfaction of the Engineer. Sieve analysis of all the aggregates to be used in the Works shall be carried out as and when required by the Engineer.

(iv)       Any aggregates not found to be of the specified/approved Standards shall be rejected by the Engineer and all such rejected material shall be removed from Site without delay.

(v)        Floors sub-base or base constructed with rejected aggregates shall be dismantled and rebuilt at the expense of the Contractor.

16.3.4  Water

Water used for mixing concrete, curing or any other operation of the Works specified herein shall be fresh, clean and free from organic or inorganic matters in solutions or in suspension. Only water of the approved quality shall be used for all constructional purposes:

16.3.5  Ceramic Tiles

Ceramic tiles shall be local, best quality white or any other colour. The size of tiles shall be as specified and shall conform to BS 1281 as per samples. The Engineer can select different colour and designs of the approved tiles for use in different locations, if not specified.

16.3.6  Terrazzo Tiles

Terrazzo tiles shall be first grade mechanically compressed type conforming to PS-531. Tiles shall be of specified sizes with a topping of 10 mm thickness composed of 1:2 cement marble chips, the base being 1:2 cement mortar. The colour quality and size of chips shall be as per Engineer’s approval.

16.3.7  Cleaning Compound

The compound used for all cleaning of terrazzo shall be an approved neutral chemical cleaner free from acid and alkali or any other material that will affect the colour or otherwise damage the terrazzo and shall not affect the conductivity of terrazzo floors.

16.3.8  Vitrified Clay Tile

Vitrified clay tiles of specified size shall be first quality of local manufacture approved by the Engineer.

16.4     Cement Concrete Flooring

The materials for C.C flooring shall be same as already specified under Clause 3, “Materials”.

16.4.1  Composition of Concrete

Concrete shall be composed of Portland cement, sand, coarse aggregate and water, all well mixed and brought to the proper consistency. The Contractor shall mix the ingredients as specified. The proportions of the various ingredients shall be determined from time to time during the progress of the Work and tests shall be made of samples of the aggregates and the resulting concrete. The mix proportions and appropriate water cement ratio will be determined on the basis of the production of concrete having required workability, density, impermeability, durability and required strength.

16.4.2  Mixing Concrete

The concrete ingredients shall be mixed in a batch mixer for not less than 1½ minutes after all ingredients, except the full amount of water, are in the mixer. The Engineer reserves the right to increase the mixing time when the charging and mixing operations fail to produce a concrete batch in which the ingredients are uniformly distributed and the consistency is not uniform. The concrete shall be uniform in composition and consistency from batch to batch except when changes in composition or consistency are required. Water shall be added prior to, during and following the mixer charge. Excessive over mixing requiring addition of water to preserve the required concrete consistency will not be permitted. The concrete ingredients shall be mixed by volumetric measurement in purpose made boxes approved by the Engineer.

16.4.3  Construction

The base course of the floor shall comprise of brick ballast of 2 inches (approx. 50 mm) mesh size. The base course shall be thoroughly compacted by suitable power rammers to the total consolidated thickness as shown on the Drawings. The interstices shall be filled with smaller size brick. The base course shall be blinded with sand and the whole surface watered. Over the well compacted base course, a layer of concrete of the required grade and thickness shall be laid, in panels of the sizes as indicated on the Drawing or as approved by the Engineer.

After the C.C bed has been cured, as directed by the Engineer, it shall be roughened and well watered before floor finishing is laid. The floor finish shall comprise of cement concrete of required grade and shall be laid in panels to the required thickness as shown on the Drawings or as directed by the Engineer. The concrete after laying will be thoroughly rammed and mortar worked up to the top and smoothed with a steel trowel.  The edge of each section into which the floor is divided should be defined by wooden screeds of the approved width and of a depth equal to the depth of the floor concrete.

Freshly placed concrete floor and completed floor portions as finished shall be protected to prevent loss of water by covering with damp hessian, damp sand or other approved material, and shall be kept constantly damp for a period of four days. The concrete shall be allowed to dry out slowly over a period of three days after wet curing is completed.

16.5     Installation of Tile Flooring

The Contractor should note that all tiles before installation should be sorted out in a proper way acceptable to the Engineer, no under/ over sized and damaged tile should be used.

When setting out the tiles, care shall be taken to establish the correct elevation for the floor. A gauge rod shall be used, indicating the overall measurement of a given number of tiles with specified joint width to reduce cutting.

After the floor has been machine finished, it should be covered with white, non-staining sand or rags to protect it while other Work is being done. After removal, the floor shall be thoroughly scrubbed.

16.5.1  General

(a)               The base shall be prepared by laying cement concrete of specified grade and of thickness as specified or as shown on the drawings.

(b)               The curing period of the setting bed shall be as directed by the Engineer. As large area of setting bed shall be spread at one time as can be covered with tiles before the mortar has set. Surplus mortar shall be removed. The thickness of setting bed in any space shall not be less than ½” (12.5 mm).

(c)               Floor and wall surfaces to receive the tiles shall be thoroughly cleaned of all dirt, dust, oil and other objectionable matters. Tiles shall be laid out from the centre line of each space in an outward direction and the pattern should be made symmetrical with a minimum number of cut tiles.

(d)               Joints between the tiles shall be of uniform width. Tiles shall be cut with a suitable cutting tool and rough edges shall be rubbed smooth. Tiles shall be laid to the straight edges.

16.5.2  Terrazzo Tiles

The terrazzo tiles will be laid to the required lines, levels and grades over a setting bed of cement sand mortar comprising of 1 part of cement and 4 parts of sand by volume.

After seven days, the terrazzo tile floors shall be machine ground to a true even surface using various grades of abrasive stores as required and directed by the Engineer. After the first grinding the floor shall be grouted with the same colour composition as used for its manufacture. The grout shall be of the consistency of thick cream and shall be brushed over the floor to fill in the joints and after 72 hours the grouting coat shall be removed by grinding till a smooth and even surface is obtained. Areas and portion of the floor inaccessible for the grinding machine shall be ground and rubbed by hand. The final gloss shall be given by polishing the surface to the satisfaction of the Engineer.

16.5.3  Ceramic Tiles

The ceramic tiles shall be laid to the required lines, levels and grades over a setting bed of cement sand mortar comprising of one part of cement and 4 parts of sand by volume and the joints filled with neat white or grey cement including vertical and horizontal covers. The tile floor shall be kept wet for at least 72 hours and no traffic should be allowed on the tiles during curing period.

16.5.4  Cement Concrete and Vitrified Tiles

The cement concrete and vitrified clay tile shall be laid to the required, lines, levels and grades over a setting bed of cement sand mortar comprising of 1 part of cement and 4 parts of sand by volume.

16.6     Terrazzo Flooring Cast-in-Situ

16.6.1  Mix

The terrazzo mixes shall be composed by weight as follows:

Plain terrazzo for all floors and bases indicated as terrazzo and not otherwise specified, shall be composed of one part cement, white or grey, and 2 parts of marble chips of the sizes and colours hereinafter specified.

16.6.2  Preparation for Terrazzo

The grade and thickness of concrete as shown on the Drawings shall be laid as under bed to receive terrazzo. The surface of the bed shall be roughened for bonding with the terrazzo finish. If the surface is too smooth it shall be roughened with a toothed chisel and prior to laying the terrazzo the bed shall be cleaned of all dirt, oil re-ease and extra loose material.

16.6.3  Division Strips

Terrazzo floors and bases shall be divided by glass/marble strips. The division strips between fieldwork and borders shall have exposed tops in full width of the strips. The division strips shall be set immediately after the spreading of the underbid, the strips being partially embedded therein, securely anchored to the sub-floor and grouted solid.

All division strips shall be set, straight to lines and to the proper level to ensure that the tops of the strips will show uniformly after grinding and smoothening operations are completed and joints and intersections shall be fitted tight. Strips shall be braced to prevent bulging during the placing of terrazzo.

Unless otherwise shown on the drawings, the divisions in field Work of large areas shall not exceed 3 feet x 3 feet and in small areas shall not exceed 2 feet x 2 feet.

Edging strips shall be placed at door ways between terrazzo and types of flooring and along the edges of all terrazzo bases or borders and adjoining other types of floor finishes or floor covering. The edging strips at door ways shall be placed in line with the step face of doors. All edging strips shall be anchored and grouted solid in the under bed or to the concrete sub-floor and braced to prevent bulging as specified for division strip.

16.6.4  Laying Terrazzo

(a)               The sub-surface shall be swept clean, thoroughly moistened, but not saturated, and slushed with a coating of neat cement grout. The under bed consisting of specified cement concrete screed shall be spread and brought to a level not less than 1/2 inch. (12mm) below the finished floor level the dividing strips shall be installed in the green under bed. The terrazzo mix shall be spread, tamped and rolled into a compact mass not less than specified thickness. After rolling additional aggregate mix shall be sprinkled over the surface to fill up all depression to take up excess moisture and to permit the terrazzo to be trowel led to a level, dense and even surface, slightly above the finish line of floor. This level shall allow for the surface grinding necessary to expose the area of aggregate, and to produce smooth leveled floor free or waves and depressions.

(b)               Seasoning

The completed terrazzo shall be allowed to season for 6 days during which time it shall be kept moist and free of traffic. The curing shall be accompanied by (1) covering with approximately 1 inch (25 mm) thickness of sand; or (2) sprinkling with water at every 10 hour interval.

(c)               Surface

Following the curing period, the terrazzo shall be machine ground to a true, even surface using a No. 24 grit followed by a No. 80 grit or finer abrasive stone. After the first grinding, the floors shall be thoroughly grouted with the same cement and colour composition as specified for the matrix of the terrazzo mix. The grout shall be of the consistency of thick cream, and shall be brushed over the floor to eliminate all pits and thoroughly fill the surface for final grinding.

(d)               Finishing

Not less than 72 hours after application, the grouting coat shall be removed by grinding. In the later stages of grinding, the grit stones or other abrasive used in the grinding machine shall be of a grain or fineness that will give the surface smooth finish. Small areas, inaccessible portions and corners which cannot be reached by the grinding machine shall be finished by hand.

(e)               Protection

The walls and all surfaces of the finished Work of other trades shall be properly protected from damage and spoiling during the process of grinding and washing of the terrazzo. After the finish grinding has been completed and the surface treatment applied, the terrazzo Work shall be covered arid protected with material, approved by the Engineer until completion of the Work of all other trades.

(f)                 Cleaning and Coating

Prior to placing the protective covering, the terrazzo floor shall be approved by the Engineer. After the Work of all other trades has been completed and the protective covering removed, all terrazzo Work shall be washed with cleaning where necessary to remove any stains or cement smears. The terrazzo shall be allowed to dry thoroughly and shall be given a sealing application of preservative material. The sealing material shall be applied in accordance with the manufacturer’s directions, leaving all terrazzo Work in clean condition as approved by the Engineer.

(g)               Skirting

The ingredients of skirting (Dado) shall be one part of cement and two parts of marble chips varying from Nos. 0-2. Skirting shall be laid over a base of plaster of specified thickness. The thickness of dado/skirting layer shall be as specified. The surface shall be ground and polished to the satisfaction of the Engineer.