SampleFloorSpecification Mesh

 

 

Sample Specification - Ground Supported Concrete Industrial Floor Slab (mesh reinforced)  A reinforced concrete ground supported slab, constructed using mechanical large-bay construction method, eg: Laser Screed (Somero www.somero.com)) with a power Enterprises Inc or other approved www.somero.com trowelled finish will be provided to all ground gr ound floor areas within the building. The slab will be designed in accordance with the recommendations of the Concrete Society’s Technical Report 34 (TR34), for a maximum uniformly distributed loading of 50KN/m2, and back-back racking leg loads as detailed on engineer’s drawings The floor should be designed to be un-restrained from the building structure as such the floor cannot be tied to external retaining re taining walls. No hairpin ties from the steel frame foundations will be permitted. Where construction joints are provided in the construction of the floor, they should be generally detailed in accordance with TR34 using permanent steel forms forms such as ‘‘Permaban Permaban Alpha joi joint’ nt’ or app approved roved equivalent, and designed so that no vertical movement occurs across the  joint. All dowels to be 6mm ‘diamond dowels’ ((110 110 x 110mm) at 450 mm centres unless otherwise specified or agreed. Where possible, the number of formed construction joints must be kept to a minimum. Sawn restraint movement joints should be designed so that the spacing does not exceed e xceed 6.5 metres and the aspect ratio between joints perpendicular to each other must not exceed 1:1.5. Cracks less than 0.3mm will be accepted but allshould effortsbe to encouraged. reduce the number of cracks by and minimise the mix width of them This is achieved good concrete design, reduced water / cement ratio and a good curing regime. Advice should be sought from a qualified flooring consultant such as Face Consultants Ltd (www.face-consultants.com (www.face-consultants.com)) A permanent steel joint such as Permaban Alpha joint AD10’ (Permaban www.permaban.com )  ) or approved equivalent to be provided Ltd, www.permaban.com approximately 1 metre in front of any loading docks to reduce restraint from the loading docks and reduce induced cracking into the main body of the floor. The slab is to be isolated from the building structure and column bases with 20mm wide isolation material that is compressible such as ‘Miothene’ or similar approved. It is essential that the isolation material is taken to

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the top of the sub base to ensure complete isolation of the slab. Isolation to the outside walls can be 10mm 1 0mm wide, again with Miothene or similar approved. All doors, internal or external, where butting up to a concrete slab or beam must have a load transfer detail incorporated. Load transfer must be achieved using a Permaban Alpha joint AD 10 or similar approved detail.   detail. The concrete should be in accordance with BS EN 206-1 and Euro code 2 and have a minimum strength of 35 N/mm2 at 28 days and a minimum flexural strength of 5.0 N/mm2. The concrete mix is to have a minimum of 325Kg/m3 of cement and a maximum water cement ratio of 0.50. The use of plasticizers and retarders will be permitted but under the strict guidance of Face Consultants Ltd (Face). Cements to be to BS EN 197-1 and aggregates to conform to BS EN 12620 and BS 882. Drying shrinkage associated with aggregates not exceed 0.075% when tested to BS EN 1367-4. A sieve curve should analysis must be presented to Face for approval. Reinforcement of the concrete floor slab will be with 1 layer of A 252 steel fabric to BS 4483. The Steel fabric is to have 50 50mm mm cover to bottom surfaces. The bottom layer to be fixed fixe d to concrete block spacers of variable depth to ensure steel is fixed within +/- 10mm of designed position. Spacing of block spacers should be such that the steel fabric does not touch the sub-base when deflected under foot load. Mesh should be lapped 300mm. All re-entrant corners at columns, loading docks and floor penetrations to have 2 number 12 mm diameter, 900mm long high tensile bars fixed to the top and bottom mesh at right angles to the corner. The ground floor slab will be constructed so that the surface regularity (flatness and levelness) is within the tolerances as defined in TR34. In free movement floor areas (all other areas are as but VNA) the floor should conform to category FM2 as defined in table 4.2. of TR34. The floor is to be independently tested by a certified floor surveyor (Face Consultants Ltd or other approved) within 5 days of construction construction.. The ground floor slab wearing surface shall have a minimum abrasion resistance of AR1 in accordance with table 4 of BS 8204-2 2002. One abrasion test is to be carried out for each 2000m2 of slab or part thereof, in accordance with BS 8204-2 2002 to confirm that appropriate abrasion resistance has been achieved. Tests, to be carried out by Face.

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Immediately after the final power trowelling operation, the floor is to be sprayed with an acrylic based, curing, sealing and hardening membrane in strict accordance with the manufacturer’s applicatio application n instructions. The floor shall not be trafficked for a minimum of seven days following the sealing operation and should not be loaded for 28 days. It is suggested that  Sika Proseal is used or similar approved. Any alternative must be that approved in advance by Face. The following morning the floor is to be first covered in water and 1 layer of 1000 gauge plastic sheeting applied to further enhance the curing regime. The plastic sheeting is to remain in place for at least 7 days. The surface of the floor is to be continually wetted for a minimum of 7 days. If a slip membrane is to be specified it must be a 1200 gauge P.I.F.A. lapped a minimum 150mm laid on a layer of sub-base with a minimum thickness as detailed on the engineer’s drawings. The sub-base shall be crushed rock or similar material to be approved by the and shall beUK graded and laid in accordance with Type 1 orn Typeengineer 2 as defined by the Highways Agency Series 800 (Specificatio (Specification for highway works, Road Pavements – Unbound materials). The sub-base is to be laid to the specified minimum thickness in maximum 300mm layers and compacted using a 10 tonne dead-weight roller with a minimum of four passes in each direction perpendicular to each other. Where necessary the sub-base can be blinded with a fine material to close the surface, sand must not be used. The Th e finished surface of the sub-base shall be within +0 to -25mm of the datum in accordance with TR34 (2003). The sub base tolerances should be checked at least the day before casting the slab and carried out by Face. Prior to concreting the slab, all roof and wall sheeting and loading doors must be fixed to provide protection from the elements. If, due to programme restraints this cannot be achieved, then temporary sheeting must be used to seal all openings. The Floor slab should not be cast where exposed to the sun and sufficient roof and wall protection must be in place before casting. All efforts should be made in the construction and detailing of the floor to reduce the possibility of random cracking. If cracks do occur, they are to be grouted with a low viscosity resin based material if wider than 0.3mm wide. All repairs to be after the defects liability period and within the winter months, what ever is the latest period. The successful contractor must demonstrate that he has previous experience in achieving the required flatness specification by providing profileograph evidence and a detailed method statement including a list of 3

 

 

all the equipment to be used to achieve the required specifications. If required the contractor must provide at least two references and offer a site visit to at least one of the references. Alternatively, the contractor must confirm that Face Consultants have been instructed to provide continuous on site consultation and instruction to assist in providing the same. Contact Face for their scale of fees fe es for these services.

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