Title:
Method of constructing foundation substructure and a building
Kind Code:
A1


Abstract:
The present invention provides a method of constructing a foundation substructure and a building involving pouring concrete between resilient sheets of insulating material, preferably polystyrene, so as to form a complete concrete shell.



Inventors:
Letton, John Caradoc (Lewes, GB)
Application Number:
11/805474
Publication Date:
11/27/2008
Filing Date:
05/23/2007
Primary Class:
Other Classes:
52/293.3, 52/309.12, 52/274
International Classes:
E04B1/04
View Patent Images:
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Primary Examiner:
HIJAZ, OMAR F
Attorney, Agent or Firm:
AMSTER, ROTHSTEIN & EBENSTEIN LLP (NEW YORK, NY, US)
Claims:
What is claimed is:

1. A method of constructing a building, comprising the steps of: a) erecting a plurality of panels to define the walls; b) installing a support rail at the height of a floor or roof; c) attaching at least one sheet of material to the support rail so as to define a floor or roof d) pouring concrete between the panels of insulating material and over the at least one sheet of material so as to form the walls and floor or roof of the building

2. The method of claim 1 wherein said panels are formed of two sheets of synthetic insulating material held in spaced relation to each other by a plurality of spacers.

3. The method of claim 1 wherein said support rail is made of lightweight cold rolled steel.

4. The method of claim 1 wherein said sheets of material are sheets of corrugated steel.

5. The method of claim 2 wherein said spacers are made of aerated concrete.

6. A building wherein at least part of one wall comprises two sheets of insulating material between which is a layer of concrete.

7. The building of claim 7 wherein said insulating material is polystyrene.

8. The building of claim 7 wherein all of the external walls of said building comprise two sheets of insulating material between which is a layer of concrete.

9. The building of any of claim 7 further comprising a first floor or roof made of concrete, and the concrete of said first floor or roof is directly bonded to the concrete of said walls.

10. The building of claim 7 further comprising a concrete foundation slab, and the concrete of said foundation slab is directly bonded to the concrete of said walls.

11. A method of constructing a foundation substructure comprising the steps of: a) laying a concrete foundation; b) securely fixing outside perimeter members to said foundation to define the outside perimeter of a wall; c) positioning foundation blocks comprising an outside perimeter sheet and an inside perimeter sheet held in spaced relation to each other against said outside perimeter members, wherein the outside perimeter sheet is taller than the inside perimeter sheet; d) securely fixing inside perimeter members against the inside perimeter of said foundation blocks; e) filling said foundation block with concrete to the height of the inside perimeter sheet; f) building the inside foundation structure up with hardcore; g) overlaying the hardcore with an insulating sheet such that the top of the insulating sheet is level with the height of the inside perimeter sheet; and h) pouring a concrete floor slab over said insulating sheet to the height of external perimeter sheet.

12. The method of claim 12 wherein said outer perimeter members and said inner perimeter members are softwood battens.

13. The method of claim 12 wherein said outside perimeter sheet, said inside perimeter sheet and said insulating sheet are made of polystyrene.

14. A foundation substructure comprising at least one foundation wall comprising two sheets of material between which is a layer of concrete.

15. The foundation substructure of claim 15 wherein said foundation wall is adjacent to a further sheet of insulating material and part of the upper surface of said foundation wall and said further sheet of insulating material support a slab of concrete.

16. The foundation substructure of claim 15 wherein said sheets of insulating material are polystyrene.

17. The foundation substructure of claim 15 wherein said further sheet of material is polystyrene.

Description:

FIELD OF THE INVENTION

The present invention relates to a method of constructing a foundation substructure and a building.

BACKGROUND OF THE INVENTION

Formworks are structures of boards that make up forms for pouring concrete in construction. To date, a self-supporting permanent formwork structure that can be put up by manhandling alone and has excellent insulation has not been produced. Furthermore, a structure that when used results in good acoustic performance, high thermal capacity, strength and resilience has not been produced.

SUMMARY OF THE INVENTION

The present invention seeks to address these issues.

According to one aspect of the present invention there is provided a method of constructing a building, comprising the steps of:

    • a) erecting a plurality of panels to define the walls;
    • b) installing a support rail at the height of a floor or roof;
    • c) attaching at least one sheet of material to the support rail so as to define a floor or roof
    • d) pouring concrete between the panels of insulating material and over the at least one sheet of material so as to form the walls and floor or roof of the building

Preferably said panels are formed of two sheets of synthetic insulating material held in spaced relation to each other by a plurality of spacers.

Preferably said support rail is made of lightweight cold rolled steel.

Preferably said sheets of material are sheets of corrugated steel.

Preferably said spacers are made of aerated concrete.

According to another aspect of the present invention there is provided a building wherein at least part of one wall comprises two sheets of insulating material between which is a layer of concrete.

Preferably said insulating material is extruded polystyrene.

Preferably all of the external walls of said building comprise two sheets of insulating material between which is a layer of concrete.

Preferably the building comprises a first floor or roof made of concrete, and the concrete of said first floor or roof is directly bonded to the concrete of said walls.

Preferably the building comprises a concrete foundation slab, and the concrete of said foundation slab is directly bonded to the concrete of said walls.

According to a further aspect of the present invention there is provided a method of constructing a foundation substructure comprising the steps of:

    • a) laying a concrete foundation;
    • b) securely fixing outside perimeter members to said foundation to define the outside perimeter of a wall;
    • c) positioning foundation blocks comprising an outside perimeter sheet and an inside perimeter sheet held in spaced relation to each other against said outside perimeter members, wherein the outside perimeter sheet is taller than the inside perimeter sheet;
    • d) securely fixing inside perimeter members against the inside perimeter of said foundation blocks;
    • e) filling said foundation block with concrete to the height of the inside perimeter sheet;
    • f) building the inside foundation structure up with hardcore;
    • g) overlaying the hardcore with an insulating sheet such that the top of the insulating sheet is level with the height of the inside perimeter sheet; and
    • h) pouring a concrete floor slab over said insulating sheet to the height of external perimeter sheet.

Preferably said outer perimeter members and said inner perimeter members are softwood battens.

Preferably said outside perimeter sheet, said inside perimeter sheet and said insulating sheet are made of extruded polystyrene.

According to yet a further aspect of the present invention there is a provided a foundation substructure comprising at least one foundation wall comprising two sheets of resilient material between which is a layer of concrete.

Preferably said foundation wall is adjacent to a further sheet of insulating material and part of the upper surface of said foundation wall and said further sheet of insulating material support a slab of concrete.

Preferably said sheets of insulating material are extruded polystyrene.

Preferably said further sheet of resilient material is extruded polystyrene.

BRIEF DESCRIPTION OF THE DRAWINGS

A specific embodiment will now be described with reference to the accompanying drawings, of which:

FIGS. 1 to 8 show the method of building construction excluding the final step of pouring concrete;

FIG. 9 shows a vertical cross-section of a wall of a building being constructed according to the method of FIGS. 1 to 8 resting on a foundation substructure;

FIG. 10 shows a vertical cross-section through a wall and floor of a building being constructed according to the method of FIGS. 1 to 8;

FIG. 11 shows a horizontal cross-section through two walls of a building being constructed according to the method of FIGS. 1 to 8;

FIG. 12 shows a schematic vertical cross-section through a panel according to the present invention; and

FIG. 13 shows a vertical cross section through the base of a column erected according to the method of FIGS. 1 to 8.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Before the building is constructed, a foundation substructure for the building is laid. As shown in FIG. 9, the foundation substructure has as its base a concrete foundation 1, which should be as level as possible (±5 mm). Softwood battens 2 are attached to the foundation around the outside perimeter of the walls using shot-fired fixings or rawlbolts at 300 mm centres. Foundation blocks comprising extruded polystyrene sheets 4,5 are positioned against battens 2, these sheets 4,5 being held together in spaced relation by spacers (not shown in the diagram). Preferably the spacers are 103*103 mm blocks of aerated concrete with a crushing strength of 7 N/mm2, and fixed in position in the foundation blocks using A9267 adhesive, as sold by Strathbond Ltd. The foundation blocks are preferably ‘Formworks F1’™ foundation blocks. External perimeter sheet 4 is higher than internal perimeter sheet 5. Softwood battens are secured onto the foundation 1 around the inside perimeter of the walls using shot-fired fixings or rawlbolts at 450 mm centres. Preferably 50*75 mm softwood battens are used for both 2 and 7.

The foundation blocks are then filled to the underside of floor slab level to form foundation walls, i.e. to the full height of panel 5 using well compacted concrete, as specified by the Engineer, usually 30 kN/m2, slump 75 mm±25 mm, maximum aggregate size 10 mm. It is important that the concrete slump is within the limits specified as too high a slump can increase formwork pressures and can lead to deformation and possible bursting. Concrete may by poured using a pump, skip or other methods, with care taken that the concrete is not placed into the formwork too quickly. The pump should have a maximum hose diameter of 75 mm, preferably with a swan-neck to reduce the velocity of the concrete. Concrete should be lightly compacted as the pour proceeds, the most suitable methods being gentle rodding with a length of reinforcing bar and tapping the outside of the formwork. The foundation walls should be checked to ensure they remain straight and plumb as they are filled and checked again when the fill is complete. Excess concrete is cleaned from the tops and surfaces of the foundation walls before it has ‘gone off’.

Hardcore 3 is placed on the side of sheet 5 which will be the inside of the building. Insulating polystyrene sheet 6 is laid over hardcore 7. DPM (acronym: Damp Proof Membrane) is then laid over insulating polystyrene block 6 and concrete floor slab 8 is poured to the height of external perimeter sheet 4. Once the concrete has set, the substructure is complete.

This insulated substructure avoids labour below ground and the excessive use of concrete that is inherent with strip and trench fill foundations respectively.

Once the substructure has been completed, construction of the building itself may be commenced, though the building may of course also be built on any other suitable foundations.

A base channel 9 is secured along the path that the walls are to be erected on, in the present embodiment around the perimeter of the concrete floor slab 8 using M10 rawlbolts at 450 mm centres. In the present embodiment the channel is a 75*130*3 mm C-section, however it is preferable to use two angles such that in the middle of the channel the concrete slab 8 is exposed. This means that when the concrete wall of the building is later poured, the building wall will form an airtight concrete-to-concrete seal with slab 8.

Turning to FIG. 2, once the channel has been secured, columns 10 are attached to the channel with two Teks™ self-drilling, self-tapping screws 11 on each side as seen in FIGS. 9 and 13. Corner columns 10a are similarly attached to the channel. The columns are made of lightweight cold rolled C section steel bolted back to back. There are holes punched in the columns to allow concrete to flow through and bond. The corner columns 10a also incorporate a square section joining piece.

As seen in FIG. 3, panels 13 are placed between the columns and the edge of the panels are fixed to the columns using 110 mm long ExFix™ fasteners at 300 mm vertical centres 12, as seen in FIGS. 9 and 11. Alternative fixings may of course be used. For example plastic tubular washers held in place by a self-tapping screw wherein the tube has a ‘mushroom’ head and the screw fits inside the tube. Such fixings have the advantage that they minimise heat transfer from the inside to the outside as the screw is screw is buried in insulation. This improves the thermal performance of the wall.

Panels 13 are preferably ‘Formworks F1’™ panels. Panels 13 comprise two sheets (13a, 13b) of extruded polystyrene held together in spaced relation by spacers 14 at approximately 500 mm centres. FIG. 12 is a schematic cross section through a panel showing spacers 14. Spacers 14 are 103*103 mm blocks of aerated concrete with a crushing strength of 7 N/mm2, and fixed in position in the panels using A9267 adhesive, as sold by Strathbond Ltd. The size of the panels may vary from 600 mm*2500 mm up to 1200 mm*2500 mm. Typically the sheets are 80 mm thick. Typically the space between the sheets is 140 mm. As can be seen from FIG. 3, sheet 13a on the outside of the wall is taller than sheet 13b on the inside of the wall. The panels are prefabricated off-site, where service ducts, windows, doors etc. may be incorporated into the panels under factory conditions.

It is evident that the use of columns separate to the panels is not essential and self-supporting panels with, for example, columns incorporated may be used.

Turning to FIG. 4, once the panels are in place, the floor support rail 15 is attached to the columns around the inner perimeter of the wall adjacent to the top of sheet 13b using four Teks™ self-drilling, self-tapping screws 16 into each column. The support rail is a 127*63 mm C-section.

As can be seen in FIG. 5, cill, head and minor infill panels 17 are then attached onto the columns using 110 mm long ExFix™ fasteners at 300 mm centres. Any reinforcement that may be required above the openings in the walls is introduced at this stage. The sections of column adjacent to doors, windows etc. are blocked with appropriate pieces of timber to prevent concrete spilling out through the holes.

Turning to FIG. 6, corrugated steel sheeting 19 is positioned on the support rail and a check is made to ensure that the corners are right angles. The sheeting has a W-section. The sheeting is secured to support rail 15 using Teks™ self-drilling, self-tapping screws 18 at 300 mm centres. Further corrugated steel sheeting 19 is then used positioned and similarly secured to the support rail so as to create the formwork for a floor or roof. The floor is propped up using Acro™ props or any similar means below temporary beams.

The steel frame thus constructed provides both temporary support to the formwork, ensuring that it is stable until the pour is complete, and it replaces reinforcing steel, which is complex and expensive to fix. The columns are specially designed to create a composite structure with the concrete. The permanent steel floor formwork holds the structure square and rigid until the concrete is poured. The structure is self-supporting. This dual function of the steel frame makes the system efficient and cost effective.

As can be seen in FIG. 8, a safety rail 20 is secured to columns for use when pouring the concrete. Any necessary reinforcement required for the walls such as starter bars, are fixed in accordance with the Engineers specifications.

The concrete may then be poured into the wall formwork. This is done in well compacted layers not exceeding 900 mm in depth. The concrete strength is specified by the Engineer, usually 30 kN/m2, with slump 75 mm±25 mm and maximum aggregate size 10 mm. Again, it is important that the concrete slump is within the limits specified as too high a slump can increase formwork pressures and can lead to deformation and possible bursting. Fibre can be added to the mix both to increase tensile strength of the concrete and to provide shrinkage crack resistance. The concrete may be poured using a pump, skip or any other suitable means, taking precautions that the concrete is not placed into the formwork too quickly. Pumps should have a maximum hose diameter of 75 mm, preferably with a swan-neck to reduce the velocity of the concrete. The concrete should be lightly compacted as the pour proceeds, the most suitable methods being gentle rodding with a length of reinforcing bar and tapping the outside of the formwork. The walls should be checked to ensure that they remain straight and plumb as they are filled and checked again when the fill is complete.

Any reinforcement required for the floor in accordance with the engineers specifications should then be positioned and secured. Such reinforcement may be a mesh 21. The concrete slab 22 is then poured onto the corrugated steel sheeting 19, and brought to the level of the top of sheet 13a.

Once the concrete has reached the required strength, this procedure may be repeated to construct upper floors. To begin repeating the procedure column extensions are bolted onto the existing columns, and the safety rail 20 is removed and stored for later use. Galvanised steel angles (23, 24) are used to locate the base of the upper panels, one of the angles 23, a 75*75*3 mm angle being attached to the concrete slab 22 and the other two angles 24, being 75*50*3 mm angle attached to the columns. All of the angles are attached using Teks™ self-drilling, self-tapping screws. 110 mm long ExFix™ fixings 25 are used to secure the top and base of each panel to the angles at 300 mm horizontal centres. When it is necessary to join two lengths of column, splice plates should be fixed in accordance with the Engineers instructions.

A finish 26 may later be applied. Finishes range from elastomeric paints through modified thin coat renders, acrylic brick and stone slips to timber cladding and more sophisticated rain screen systems.

The method as described has many advantages. The insulating panels are left in place after they have been used as formwork thus providing insulation. Conventional formwork has to be removed, transported, and stored or disposed of, a wasteful and expensive process. The insulation provides thermal performance and protection for the concrete throughout its life. Expanded polystyrene may be used in place of extruded polystyrene; indeed, any suitable material may be used.

The floors and roofs are cast on corrugated steel formwork, and together with the walls provide a strong airtight shell.

This concrete shell provides structural strength and durability. Unlike pre-cast panel or timber frame systems, airtight integrity is automatically achieved and maintained for the life of the building. This allows for efficient ventilation with heat recovery. The inherent strength of the concrete shell creates a secure building resistant to fire, extreme weather and physical attack.

The concrete shell provides thermal capacity, resulting in lower energy use and a healthier environment. The savings in energy during the buildings life due to thermal capacity contribute significantly to lower running costs and sustainability. Typical wall panels have 80 mm of insulation on each side of a 140 mm cavity and together with finishes achieves a U value of 0.17 w/m2/K. This can be increased by adding additional insulation.

The concrete shell also provides acoustic mass; i.e. the building is highly insulated from sound.

The above embodiment is by way of example only, many variations are possible without departing from the scope of the invention.