IES990939A2

IES990939A2 - Precast suspended floor system

Info

Publication number: IES990939A2
Authority: IE
Inventors: Sean Farrington
Original assignee: Stresslite Floors Ltd
Priority date: 1999-11-10
Filing date: 1999-11-10
Publication date: 2000-12-13

Abstract

A floor construction comprises a plurality of pre-cast reinforced (or pre-stressed) planks (10) laid substantially parallel to one another on ground infill (14) and supported at each end by building foundations (16) or blockwork. Each plank (10) is thermally insulted from the ground infill and from its neighbours by thermally insulating material (12, 28) under and between the planks, and a layer of concrete (30) covers the planks and the thermally insulating material. <Figure 1>

Description

This invention relates to a floor construction for a building .

According to the present invention there is provided a floor construction comprising a plurality of pre-cast reinforced or prestressed planks laid substantially parallel to one another on ground infill and supported at each end by building foundations or blockwork, each -plank being thermally insulted from the ground nliii and from its neighbours by thermally insulating material under and between the planks, the construction further including a layer of concrete covering the planks and the thermally insulating material.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a cross-section through a floor constructed according to the embodiment of the invention; Fig. 2 is a cross-section through the floor taken at right angles to Fig. 1; and Fig. 3 is a perspective view of one of the pre-cast planks used in the floor.

Referring to the drawings, the floor construction according to the embodiment of the invention comprises a plurality of pre-cast reinforced or prestressed concrete planks 10 each having a layer 12 of thermally OPEN TO PUBIX INSPECTION pi29075. rev IE990939 insulating material, preferably polystyrene, adhered to its bottom surface and extending substantially fully along the length thereof. The planks 10 are laid substantially parallel to one another on ground infill 14 between building foundations or blockwork 16, the polystyrene layers 12 spacing the planks 10 from the infill 14 by the thickness of the layers. The infill 14 is covered with a gas permeable membrane 18, such a sheet polythene, prior to laying the planks.

The planks 10 are of a known type, and one is snown in Fig. 3. The plank 10 comprises an elongated pre-cast concrete body 20 having a shallow rectangular crosssection with embedded longitudinal steel reinforcing girder 22. The body 20 also has a plurality of inverted V-shaped steel members 24 embedded therein which project from the upper surface of the body and which are welded at their tips to a further longitudinal steel girder 26. Such a plank is sold to the building industry under the name Thermalite plank. The polystyrene layer 12 is bonded to the opposite side of the plank to the girder 26.

Each plank 10 extends fully across the width of the proposed floor area and is supported at each end by the foundations or blockwork 16 on opposite sides of the floor area. Although only one end of a plank 10 is shown supported by foundations 16 in Fig. 2 it should be understood that the opposite end of the plank is likewise supported by the foundations or blockwork at the opposite side of the floor area. pi2907S. rev IE990939 The ground infill 14 has a slight rise in the middle, peaking approximately midway along the length of the planks 10, thereby creating a slight upward camber towards the ends of the planks and in a direction substantially parallel to the planks. This puts he planks 10 under a slight compression, resulting in greater strength in the finished floor.

At each opposite edge of the floor area the outermost plank 10A, Fig. 1, of the parallel set of planks 10 rests by its longitudinal edge on tne roundations or blockwork 16 (only one such plank is seen in Fig. 1 but the equivalent arrangement applies at the opposite edge of the floor area). As seen there may be two immediately adjacent planks at the opposite edges of the floor for additional strength or trimming at the edges .

The lateral gaps between adjacent parallel planks are filled with blocks or slabs 28 of a thermally insulating material, preferably polystyrene, which are inserted between the planks 10 and rest on the membrane 18. The blocks 28 occupy substantially the full width and length of the gap between the planks 10 and have a depth at least equal to the combined depth of the plank 10 and layer 12 so that the upper surface of the blocks 28 are substantially at the same height as, or slightly above, the upper surface of the body 22 of the planks 20.

A layer of concrete screed 30 is poured over the planks 10 and polystyrene blocks 28 to a depth covering the girder 26, the concrete layer containing a steel pi29075. rev IE990939 reinforcing mesh 32. When the concrete 30 sets the inverted V-shaped members 24 key the planks 10 to the concrete layer 30 resulting in a complete floor.

Also, after the concrete 30 has set the infill 14 will subside, leaving a small void area under the floor. Hence vents 34 are provided in the foundations or blockwork 16 and outer leaf 36 of the cavity wall 38 forming the exterior wall of the building. ine advantages or one foregoing construction are: (a) Less concrete is used because of the polystyrene blocks between the planks. (b) The floor is highly insulated through the use of the polystyrene below and between the planks. (c) Less ground preparation is needed. (d) The floor will take heavier loads. (e) Since the floor is laid on ground infill clay from the foundation excavation, this material is not required to be removed from site.

The invention is not limited to the embodiments described herein which may be modified or varied without departing from the scope of the invention. pi2 907 5. rev

Claims

1. A floor construction comprising a plurality of pre-cast reinforced planks laid substantially parallel to one another on ground infill and supported at each end by building foundations or blockwork, each plank being thermally insulted from the ground infill and from its neighbours by thermally insulating material under and between the planks, the construction further including a layer of concrete covering the planks and rhe thermally insulating material.

2. A floor construction as claimed in claim 1, wherein each plank has a layer of thermally insulating material adhered to its bottom surface and blocks or slabs of thermally insulating material substantially entirely fill the gaps between adjacent planks.

3. A floor construction as claimed in claim 1 or 2, wherein each plank has means projecting from its upper surface for keying the plank to the overlying concrete layer .

4. A floor construction as claimed in claim 1, 2 or 3, wherein the thermally insulating material is polystyrene . 5. A floor construction as claimed in any preceding claim, wherein the ground infill has a slight rise in the middle to create an upward camber in a direction substantially parallel to the planks. pi29C7 5. rev IE990939 6. A floor construction as claimed in any preceding claim, wherein the ground infill is covered with a gas permeable membrane.

5. 7. A floor construction as claimed in claim 6, wherein the membrane is sheet polythene.