CODE OF PRACTICE FOR THE CONSTRUCTION OF HOUSES:

Code of Practice for the Construction of Houses: An Instruction Manual for Foremen and ExperiencedArtisans1ScopeThe information in this Code is designed to certify residential contractors so that theycan construct homes in the Caribbean that are less vulnerable to natural hazards.Plumbing and electrical standards are not included in this Code, but can be found inthe national building standards.2Normative ReferencesThe following documents were used in the preparation of the Code.a)b)c)d)3Barbados National Standards Institute, Barbados National Building Code, 1993;Organisation of Eastern Caribbean States, Grenada Building Guidelines, 1999;Virgin Islands, Building Regulations, 1999;Belize Chamber of Commerce and Industry, Belize Residential ConstructionStandards, 1999.Terms and DefinitionsThe following terms and definitions are relevant for this document.House - single family dwelling.Joint – connection between two structural elements.Lap length – distance where two reinforcing bars are spliced.Competent authority – the government’s regulatory department responsible for buildingstandards.Set back – distance from the boundary to the external wall of the building.Safe building – constructing a building with a low vulnerability to natural hazards.Illustration – drawing.Buildability - the extent to which the design of the building facilitates ease ofconstruction, subject to the overall requirements for the completed building.Pyroclastic flows- normally result from volcanic eruptions. They are fast movingfluidized bodies of hot gas, ash and rock which can travel away from the vent at up to150 km/h. The gas is usually at a temperature of 100 oC to 800 oC. The flows normallyhug the ground and travel downhill under gravity, their speed depending upon thegradient of the slope and the size of the flow.Page 8 of 67

Code of Practice for the Construction of Houses: An Instruction Manual for Foremen and ExperiencedArtisansWell graded granular fill – granular fill with a good representation of particle sizes overa wide range.Plastic chairs – a seat for steel reinforcement used to raise the reinforcement to thecorrect level.Raft foundation – a foundation that incorporates the wall foorings into the floor slab.Lintel – a horizontal beam over a window or doorway.Epoxy grout - A two-part grout system consisting of epoxy resin and epoxy hardener,especially formulated to have impervious qualities, stain, and chemical resistance.4General PrinciplesThis course is designed to provide construction foremen with specific information toreduce the vulnerability of houses to natural hazards in the Caribbean.5Pre-construction planningFor constructing a new building the following are required:a)b)c)d)e)f)g)h)i)Page 9 of 67planning approval;contract with the client;an understanding of safe building;the selection of quality material;proper storage of construction materials;the protection of reinforced concrete;the use of good quality joints;the use of adequate reinforcement lap lengths;an understanding of structural stability methods.

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced Artisans5.1Planning approvalBefore construction starts, planning approval from the competentauthority shall be obtained by the home owner. The builder wouldneed the following information which would be obtained from anapproved plan:a) accurate and identifiable lot boundary markers;b) distances from the lot boundaries to the house.c) the provision for sewerage disposal.Drawing (Dwg) 1.15.2 Contract with the clientBefore the contractor or builder starts working, he should have awritten contract with the homeowner or client. The contractessentially describes the responsibilities of each party, and the rulesfor resolving disputes. Construction contracts can be obtained fromthe local architectural association1.5.3 Safe BuildingSafe building includes the following:a) building on stable soil and in an area not prone to naturalhazards; (See 6.1)b) using good quality building materials; (See 5.4)c) constructing the materials properly to obtain good qualitybuilding elements (footings, floor, wall, roof, etc);( See 5.4)d) connecting the building elements together properly; (See5.7)e) bracing the building elements properly. (See 5.9)5.4Dwg 1.2Quality of MaterialsQuality materials shall be used in order to reduce the risk ofextensive maintenance to the building. Table 1 describes thespecifications for common construction materials. A Foreman’schecklist is provided in Annex A.1For example, in Barbados, the Barbados Institute of Architects(tel. 246 430-0956, e-mail:bia@sunbeach.net),Page 10 of 67Dwg 1.3

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced ArtisansTable 1 – Quality of MaterialsStructural MaterialSpecificationsCement – bonds theCement of approved specification shall2sand and stone.be used.SandStoneWaterReinforcementConcrete – formsstructural elements.Formwork releaseagentSand obtained from inland source, freeof clay, organic material, and brokenshells.Crushed stone or gravel with aminimum size of 5 mm (¼”) and amaximum size of 20 mm (⅞”) and freeof a coating of dust.Clean, drinkable water.To CARICOM standard with yieldstrength 460 MPa, or equivalent, andreasonably free from rust. Reinforcingbars (rebars) to be tied together usingmild steel tying wire.Concrete mix (1:2:4) producing acompressive cube strength ofapproximately 21 n/mm2 (3,000 psi) at28 days.Effective release agents which are lessharmful to the environment should beport landcementDwg 1.4Dwg 1.5Dwg 1.7Dwg 1.6port landcementused.3Concrete curingMortar – bondsconcrete blocks.Concrete blocks forms structuralelements.Effective curing methods includekeeping the concrete wet continuouslythrough water ponding, spraying, orsaturated covering material (hessian,burlap, sand, sawdust, straw),polythene covering, or spray-on curingcompoundsA good mortar mix effectively binds theconcrete blocks together.4Minimum compressive strength 7MPa (1025 psi) on the gross area.Use normal Portland cement Type 1 or equivalent. However, for concretein contact with soils with high sulphate content, Sulphate ResistantPortland cement Type 5 or equivalent can be used.3For example, this concrete strength can be achieved by the followingmixture:1 bag Portland cement 2 cu ft sand 4 cu ft stone 5 gals water to bepoured within 1 1/4 hours after mixing2Vegetable oil based release agents are less harmful to the environmentthan mineral based, which are less harmful than engine oil based agents –but they are all effective release agents.3Page 11 of 67Dwg 1.8Dwg 1.10Dwg 1.9

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced ArtisansStructural MaterialClay hollow brick(blocks)-formsstructural elementsDamp proofingmembrane (DPM)Timber framingAnchor Bolts inConcreteNails in timberRoof metal sheetingStructural SteelSelf Tapping ScrewsSpecificationsSpecification in accordance to ASTM C34. TTS 587 for hollow clay blockvertical core specifications, TTS 16 35510:1986 for hollow clay blockhorizontal core specifications,or similarapproved specificationsDPM to be 500 gauge (125 microns)polythene vapour barrier with 350 mm(1’-2”) laps and taped.Sound, straight, and well seasonedtimber with the moisture contentbetween 15% and 19%. Timber shouldbe pressure treated against insectattack.High strength Grade 8.8 with 40 mm(1½ “) diameter 3 mm (⅛”) thickgalvanised steel washers.8d galvanised common wire nails.0.5 mm thick profiled metal sheets.Z, C, W section in accordance withCARICOM or equivalent standard.Used as fasteners for cold formedsections. ( Welding is not to be used)Dwg 1.11bDwg 1.12Dwg 1.13Dwg 1.145.5 Storage of Construction MaterialsBefore construction materials become part of the permanent work,they need to be protected by being properly stored. Areas on thesite therefore need to be identified for adequate storage ofconstruction materials. Table 2 describes some suitable storagemethods.A good mortar mix (1:3) 1 bag Portland cement type 1 or equivalent 3cu ft sifted sand to be used within 1 hour after mixing.4Page 12 of 67Dwg 1.15

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced ArtisansConstructionMaterialCement bagsSand and stoneTimberReinforcing barsTable 2 – Storage of MaterialsStorageComment100 mm (4”) off thefloor and coveredwith damp proofmaterialCovered100 mm (4”) off theground and coveredwith damp proofmaterial.100 (4”) mm off theground and coveredwith damp proofmaterial.To prevent thecement from gettingwet thereby hardand unusable.To prevent themfrom being blown orwashed away.To reduce wet rotand deformation.port landcementDwg 1.16Dwg 1.17Dwg 1.18To reducecorrosion.Dwg 1.195.6Protection of Reinforced Concrete (RC)The structural materials shall also be protected from the naturalenvironment and from fire. Concrete cover is used to protect thereinforcement from corrosion and fire. To provide adequate fireprotection to reinforced concrete (RC), the structural members shallhave the minimum dimensions and concrete cover as shown inTable 3.Dwg 1.20Table 3 – Protection of Reinforced Concrete (RC)Reinforced Concrete ncrete CoverRating (h)Foundations – surfaces in75 mm (3”) 4contact with earthSlabs - minimum thickness 10025 mm (1”)1.5mm (4”)Beams - minimum width 150 mm 40 mm (1½”)1.5(6”)Internal Columns - minimum30 mm (1¼”)1.5width 250 mm (10”)External Columns - minimum30 mm (1¼”)1.5width 200 mm (8”)Dwg 1.21Dwg 1.22Page 13 of 67

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced Artisans5.7Quality of ConnectionsGood quality connections can reduce the risk of separation of thebuilding elements during natural hazards. Table 4 describes somesuitable building connections.Table 4– Building ConnectionsStructural ElementsConnectionsRoof Sheeting to Timber25 mm (1”) long screws at 150 mmpurlins (battens or laths)(6”) centres at ridges and ends and300 mm (12”) centres elsewhere.Screws at 150 mm (6”) centres.Timber purlins to roofsheathing (Tongue &groove board, plywood, orTexture T-11 board.)Sheathing to raftersSheathing connected to raftersusing 25 mm (1”) long screws at150 mm (6”) minimum centres.Rafters to RC perimeterHurricane straps embedded intobeam.beam. Use 3.15 mm (⅛”) diametergalvanised nails to connect strap torafter.Structural Steel RoofSteel sheeting shall be fastened toRoof sheeting to Z purlinspurlins using galvanized screws thatare at least 50 mm (2”) long. Wherecorrugated sheeting is used, thescrews shall be driven through thecrown of the corrugation.Dwg 1.23Dwg 1.24Z purlins to steel beamsZ purlins 100 mm (4”) x 1.5 mm(0.06”) thickness, 0.6 m (2’)spacing.Steel beams to RC beamAnchor bolts should be used, epoxygrouted with 100 mm (4”) minimumembedment into RC beam.RC perimeter beam toconcrete block wallConcrete block wall to RCfootingFor timber walls, wall platePage 14 of 67Exterior walls: 12 mm (½”) diameterbars at 600 mm (2’) centres.Interior walls: 12 mm (½”) diameterbars at 800 mm (2’-8”) centres.12 mm (½”) diameter bars at 600mm (2’) centres.Galvanised hurricane straps with 4Dwg 1.25

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced ArtisansStructural Elementsto timber studs to sole plateto foundationFooting to groundConnectionsx 8d galvanised common wire nailsor two 12 mm (¼”) dia. bolts in eachmember.In soil: Cast bottom of footing 900mm (3’) below surface.In Rock: Cut 50 mm (2”) minimuminto rock.5.8Reinforcement Lap LengthsReinforcement shall have adequate lap lengths to allow the load tobe transferred from one bar to the next. The lapped bars should betied together using tying wire. Table 5 shows some minimum laplengths.Table 5 – Lap or Splice DistancesBar Diameter(mm)6 (¼”)8 (⅜”)10 (2/5”)12 (½”)16 (¾”)20 (⅞”)25 (1”)Page 15 of 67Lap Distance(mm)300 (12”)400 (1’-4”)500 (1’-8”)600 (2’-0”)800 (2’-8”)1000 (3’-4”)1200 (4’-0”)Dwg 1.27Dwg 1.26

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced Artisans5.9Structural StabilityGood quality bracing methods can keep the building stable andallow the building connections to work as they were designed toduring natural hazards. Table 6 describes some suitable bracingmethods.Table 6 – Bracing MethodsStructural ElementsConnectionsTimber foundations50 mm x 100 mm (2”x4”) Y or Xbracing in both directions connectedusing bolts or lag screws.Timber wallsThree 50 mm x 100 mm (2”x4”)diagonal bracing at each walljunction connected using bolts or lagscrews. Galvanized metal provide asuitable bracing.Concrete block wallsThe corner core and the adjacentcores to have 12 mm (½”) diameterreinforcing bars. 6 mm (¼”)diameter rebar shall connect theadjacent cores to the corner core ateach wall junction every othercourse, and the cores filled withconcrete.RC beam12 mm (½”) diameter reinforcing barshall lap each bar 600 mm (2’) ateach junction.Dwg 1.315.10 Typical pre- construction planning detailsPage 16 of 67Dwg 1.28Dwg 1.29Dwg 1.30

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced ArtisansThe following figures describe some pre-constructionplanning concepts.Figure 1- Hatching patternsPage 17 of 67

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced ArtisansFigure 2- Cover details for reinforced concrete membersPage 18 of 67

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced ArtisansFigure 3- Foundation anchorage- stud to foundation connectionPage 19 of 67

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced ArtisansFigure 4-Typical wall corner detailPage 20 of 67

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced ArtisansFigure 5- Typical wall junction detailPage 21 of 67

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced ArtisansFigure 6- Blockwall end detailPage 22 of 67

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced ArtisansFigure 7- Blockwall junction detailPage 23 of 67

Code of Practice for the Construction of Houses: An Instruction Manual forForemen and Experienced Artisans6Site preparation6.1 Site conditionBefore construction begins, ensure that the land is suitable forbuilding e.g. it should not be unstable or prone to flooding. Thehouse should be oriented to take advantage of the natural lightingand ventilation. Where there is doubt or uncertainty of thebuildab

8.3 SUSPENDED REINFORCED CONCRETE FLOOR SLAB ON PAD FOOTINGS.44 8.4 SUSPENDED TIMBER GROUND FLOOR SUPPORTED ON REINFORCED CONCRETE BEAMS.46 8.5 TYPICAL FLOOR D . as lending institutions which offer residential mortgages around the Caribbean was established by CDERA to ela