Hollowcore

Cornish Concrete Products Quicklay Hollow Core Floor provides a fast labour saving method for laying suspended flooring.  Floor Planks are nominally 1200mm wide, purpose made to suit particular requirements, prestressed with continuous longitudinal voids achieved by using polystyrene void formers.
 
Hollow Core Floors are typically used in residential, educational, commercial and industrial applications, and CCP’s design allows for excellent span to depth ratios.
 
They are inherently, fire, sound, rot and pest resistant due to their composition. Their mass helps reduce energy demands within buildings, thereby making them more environmentally sustainable in the long term.
 
Solid Ends – Floor planks are wet cast and have solid ends. This eliminates the risk of water or other contamination in the cores and improves the shear capacity at the bearing point. There is also no additional work required on site to close open cores.
 
Speed – Quicklay Hollow Core Floor planks have cast in certified lifting eyes allowing for safer and quicker speed of installation. It also removes the risk of damage to the edges of units and the soffit from chains and “barring in” of units.
 
Off Site Manufacture - Planks are made under factory controlled conditions achieving a high quality finish. All planks are manufactured with “ecocrete”, CCP’s environmentally friendly concrete which contains a minimum of 80% secondary sourced materials.
 
Service Holes and Notches – All service openings and notches around columns are easily formed in hollow core flooring and can be manufactured to precise dimensions during production.
 
Fire Resistance – All Hollow Core Floors will achieve one hour fire resistance. Solid ends further improve fire retardation.
 
Sound Resistance – Quicklay Hollow Core Floors have a high resistance to both airborne and impact sounds, as cores are made from polystyrene which further acts as an acoustic barrier. Floors are also simply designed in accordance with EFC6 and EFC7 robust standard details and therefore do not require pre-completion site tests.
 
Thermal Mass and Thermal Performance – As units are cast in dense concrete, they have excellent thermal mass properties which within the fabric of a structure help reduce energy consumption by absorbing large heat gains and radiating that heat out when the temperature falls. With integral polystyrene void formers, thermal performance is further enhanced by approximately 25% over conventional air void cores.
 
As units are wet cast with specific lifting arrangements, soffits can be left exposed for direct decoration, thereby maximising the thermal mass effect. However, as with all prestressed floors, units have a camber (see notes on camber below), so customers requiring flat soffits with a high quality finish should consider CCP’s “Demidec” and other flat soffit floor options. Customer's wishing to use CCP's Hollow Core Floor Panks with an exposed soffit will need to notify CCP in advance so that plank layouts can be adjusted to suit (as narrow planks have no chamfered edge and are usually fabricated with built-in width tolerance) and to ensure that soffits are made good as required to the agreed standard.

Floor Depths – CCP Hollow Core Floor Planks are manufactured in 100mm and 150mm solid, 150mm, 200mm, 250mm and 300mm hollow core options.

Typical Sections – Below are diagrams illustrating typical sections for Hollow Core and Solid Slab options:

115mm solid

150mm solid

150mm Hollow Core

200mm Hollow Core

250mm Hollow Core

300mm Hollow Core

Enhanced Structural Performance – The use of high strength concrete combined with prestressing steel tendons offer far greater span to depth ratios than traditional flooring systems. As Quicklay Hollow Core Floor Planks are wet cast, the restrictions on wire patterns associated with extruded and slip formed methods of production with open cores are removed. Thus, span to depth ratios can be further enhanced with additional prestressing tendons.

Camber – All prestressed concrete units have a camber. The degree of camber is dependent on a variety of factors and CCP Quicklay Hollow Core Floor Planks are designed to have a camber of no greater than L/300. Variations in camber will be within the tolerances specified in BS81110, except where adjacent planks are spanning different lengths, or where there are large openings cast in. Consideration should be given to camber when selecting floor finishes.

Grouting – The joints between units will require grouting in with a minimum of C30 grade concrete with a maximum aggregate size of 10mm. Once the floor planks have been structurally grouted in, the floor will provide a diaphragm action for the structure.

Working Platform – Once the planks have been placed and grouted, an immediate working platform is created for follow-on trades. In most cases, propping is not required and so the area below the floor remains free from congestion allowing other trades to progress unhindered.

Progressive Collapse – Preformed slots can be cast in planks during manufacture for progressive collapse. For structures with five stories or more, CCP can supply and detail a “Demidec” solution with floor planks spanning continuously to act as a “strong” floor.

Installation – CCP can provide a suitably trained and qualified installation team to carry out the erection of the floors (and stairs, if required). Full site specific method statements, lift plans and risk assessments will be provided. Any overhead obstructions or suitable hard standing for a crane will be discussed with the site team prior to any installation work commencing and these requirements will form part of the method statement.

Design – Design work is carried out by CCP’s in house design team.

Drawings and Software – Once an order has been placed, CCP will issue layout drawings for the works to be carried out. These drawings show the supporting structure for the precast units, position of service holes, details of loading and floor finishes and typical sections through the floor. These drawings will be issued to all parties for approval. Manufacturing, loading and erection sequencing is carried out using the latest state of the art software to ensure that the transition from concept to outcome is as seamless as possible. 

Composite Slab – Hollow Core Floor Units can be designed to act compositely with an insitu concrete topping.