GB2571617A

GB2571617A - Foundation block

Info

Publication number: GB2571617A
Application number: GB1900308.6A
Authority: GB
Inventors: Fulwell Martin; Chadwick Nigel; Robert Patrick; Thomas Colin; Huxley Andrew
Original assignee: Besblock Ltd
Current assignee: Besblock Ltd
Priority date: 2018-01-09
Filing date: 2019-01-09
Publication date: 2019-09-04
Anticipated expiration: 2039-01-09
Also published as: EP3737801A1; GB201800327D0; WO2019138221A1; GB2571617A8; GB201900308D0; GB2571617B

Abstract

A cuboidal foundation block 1 includes a first support surface 11 for supporting a structure assembled on the block, and a second laying surface 20 opposite the first support surface for laying on the floor of a foundation trench. The block comprises two elongate block supporting side portions 2 separated from each other and joined in parallel at each end by opposing end walls 3. The first support surface is a continuous unbroken surface and the side portions and the end walls are formed integrally from concrete. Each of the elongate side portions may be formed of two parallel side walls connected by at least three rib walls 7 defining at least two voids 6. The elongate side portions may be joined by an internal reinforcing wall parallel to the end walls, the end walls and reinforcing wall being integrally formed from concrete. The block may comprise a concrete mix by volume of 70% pumice and expanded clay together, 15% washed sand, and 15% cement. The block may be one-part and produced by compression moulding. The block may be layed to form a double-skinned wall with a cavity between the walls.

Description

FOUNDATION BLOCK

The present invention relates to a foundation block. In particular, embodiments of the present invention relate to one-piece concrete foundation blocks for use in making foundations for houses and other similar buildings.

Presently, there are two main types of foundation blocks used in underground foundations. The first type is a one-piece block made from aerated concrete. This is a lightweight form of concrete that simultaneously provides structure, insulation and fire and mould - resistance. When the constituent elements are mixed together and cast, several chemical reactions take place, depending on the specific constituents chosen. A key reaction is the “foaming” process in which gas bubbles are created, often doubling the volume of the raw mix.

There are a number of problems associated with these aerated blocks. Firstly, a key component that is essential for the foaming process is fly ash, or pulverised fly ash. Such fly ash is in increasingly short supply. Fly ash is predominantly formed as a biproduct of coal combustion in coal-fired power plants. As increasing numbers of these plants are closed or repurposed, it is becoming important to find alternative methods of either forming aerated concrete, or of using non-aerated concrete so as to compensate for the supply problems associated with the fly ash necessary for the aerated concrete foaming process.

Additionally, aerated concrete is highly absorbent. This is not a problem once the foundations have been installed, but can be during the construction process. Wet or rainy conditions may expose the blocks to water if they are not isolated from the weather. Some forms of aerated concrete can increase in weight when exposed to water. For health and safety reasons, or due to the operational limitations on normal building equipment, it may not be possible then to install and move heavy, water-logged, aerated concrete blocks. The increase in weight caused by absorption of water can make the product exceed the maximum weight set by the UK Health and Safety Executive for repetitive manual handling. Progress on building foundations and hence the structure to go on top of the foundations may have to be significantly delayed until wet blocks have dried out.

It is desirable to produce a foundation block that is not made from aerated concrete.

The second type of concrete blocks used in underground foundations are two-part blocks. In two-part foundations, blocks are aligned to form the inner and outer walls of the foundation. These two blocks define a cavity in between. This cavity is retro-filled with “weak-mix” concrete after the two elongated blocks are placed in position. The retro-filling is necessary to provide internal support for the blocks against the inward pressure exerted by the surrounding ground when the foundation trenches are filled in around the new foundation. Because the new blocks used are each significantly smaller than the one-piece aerated concrete blocks described above, they can be formed from a dense aggregate concrete composition without becoming too heavy to be easily handled. There is therefore no need for fly ash or the foaming process during production. These heavier concrete blocks can instead be formed by a compression moulding method.

There are a number of problems associated with foundations made of two-part blocks. The construction time is significantly longer than when using one-part blocks. Not only are there two separate blocks that need to be installed and held in position, the retrofilling process is also very time consuming.

The present invention provides a foundation block for use in construction, the block including a first support surface for supporting a structure assembled on the block, a second laying surface opposite the first support surface and for laying on the floor of a foundation trench or similar, two opposing side walls and two opposing end walls connecting the support and laying surfaces, the block comprising two elongate block supporting side portions separated from each other and , each block supporting side portion being configured to withstand a downward force from a block structure assembled on the first support surface of the foundation block; the side portions joined in parallel at each end by the opposing end walls to form a cuboidal foundation block, the end walls configured to withstand an inward force from matter surrounding the block when the block is in use; wherein the first support surface is a continuous unbroken surface and wherein the side portions and the end walls are formed integrally from concrete. .

Such a foundation block is lighter and easier to handle than standard concrete blocks. The combination of a cavities defined by the end walls and two side portions with the continuous support surface results in a light and strong structure on which it is efficient and relatively easy for a bricklayer to lay a single or double course of building elements such as bricks. It also does not require time-consuming retro-filling or fly-ash to make it light enough for safe handling. The reduction in material necessary to make it also has environmental and cost benefits.

Preferably the width of each of the elongate side portions corresponds approximately to the width of a course of the building elements to be built on top pf the foundation block and the width of the space between those elongate side portions defined by the end walls corresponds approximately to the width of the cavity or space to be provided between the walls to be built on the respective elongate side portions.

Preferably the width of each of the elongate side portions corresponds to the width of a building brick.

This allows for efficient construction, and support of a cavity or double-skinned wall on top of the foundation block.

Preferably the width of the elongate side portions is approximately 100 mm.

Preferably the width of the space between those elongate side portions defined by the end walls corresponds approximately to the width of the wall cavity or space to be provided between a double wall comprising walls to be built on the respective elongate side portions.

Preferably each of the elongate side portions is formed of two elongate substantially parallel side walls connected by a plurality of rib walls defining at least one void.

Preferably each of the elongate side portions is formed of two elongate substantially parallel side walls connected by at least three rib walls defining at least two voids.

Preferably the elongate side portions are further joined by an internal reinforcing wall, parallel to the end walls; the end walls and reinforcing wall together configured to withstand an inward force from surrounding matter when in use; and, wherein the side portions, the end walls and the reinforcing wall are formed integrally from concrete.

Preferably the walls are each 15-30 mm thick.

Preferably the walls are approximately 20-25 mm thick.

Preferably the block comprises the following concrete mix (approximate percentages by volume):

i) pumice and expanded clay together 70% (+/-10%) ii) washed sand 15% (+/-10%) iv) cement 15% (+/-10%)

v) strength improver additive

This makes for a strong, lightweight and easy to cast or mould block.

Alternatively the pumice is approximately 50% and the expanded clay approximately 20%. The percentage of pumice can depends on the weight of the other constituents and the extent to which the density of the complete mix needs to be reduced. Alternatively, the expanded clay constituent may alternatively be absent.

Preferably the block is produced by compression moulding.

The present invention in a second aspect provides a method of building a foundation for a walled building, the method comprising the steps of:

a) providing a plurality of foundation blocks as defined for in the first aspect of the invention,

b) placing said foundation blocks in a trench to form a substantially contiguous length of foundation blocks,

c) laying a wall on top of said foundation blocks.

The present invention in a third aspect provides a method of building a foundation for a walled building, the method comprising the steps of:

a) providing a plurality of foundation blocks as defined in the first aspect of the invention,

b) placing said foundation blocks in a trench to form a substantially contiguous length of foundation blocks with their laying surfaces placed on the floor of the trench,

c) laying a wall of blocks on the portion of the support surfaces of those foundation blocks corresponding to an elongate block supporting side portion top of said foundation blocks.

Preferably the step of laying the wall includes laying a double-skinned brick or block cavity wall.

Relative expressions like top, bottom, side and end are used to refer to the orientation taken when the block is in use or placed ready to forma foundation and support a structure thereon.

Preferred embodiments and invention will now be described by way of non-limiting example with reference to the attached figures in which:

Figure 1 is a top perspective view of a foundation block embodying the present invention;

Figure 2 is a bottom perspective view of a foundation block embodying the present invention;

Figures 3a and 3b illustrate a cavity wall constructed on top of a foundation using and/or embodying the present invention;

Figures 4a to 4d illustrate the dimensions of the foundation block of figure 1 where figure 4a is a bottom perspective view of the block, figure 4b is a bottom plan view, figure 4c is a side cross-sectional view and illustrating the depths and shape of the voids in the block and figure 4d is an end cross-sectional view illustrating the depths and shapes of the voids;

Figures 5a to 5d illustrate the dimensions of an alternative foundation block where figure 5a is a bottom perspective view of the block, figure 5b is a bottom plan view, figure 5c is a side cross-sectional view and illustrating the depths and shape of the voids in the block and figure 5d is an end cross-sectional view illustrating the depths and shapes of the voids; and

Figures 6a to 6d illustrate the dimensions of an alternative foundation block where figure 6a is a bottom perspective view of the block, figure 6b is a bottom plan view, figure 6c is a side cross-sectional view and illustrating the depths and shape of the voids in the block and figure 6d is an end cross-sectional view illustrating the depths and shapes of the voids.

Referring to Figures 1 and 2, a foundation block 2 comprises two elongate side portions 2 coupled by end walls 3 and an internal rib 4. The end walls 3 and central internal rib 4 define central voids 5. The elongate side portions 2 each include a number of voids 6 defined by side portion internal ribs 7, side portion internal wall 8, side portion external wall 9 and side portion end walls 10. The side portion external walls 9 are also the side walls of the foundation block of which the side portions are a part. The block has a solid top or supporting surface 11 (see, for example, figures 3c and 3d) for supporting building elements or blocks such as bricks or breeze blocks thereon. The surface 20 of the foundation block opposite the support surface is a laying or bottom wall 20 for on which the block rests when it is in use (i.e. placed to form a foundation).!

In use when building a foundation (see figures 3a and 3b), a trench is dug at the location where walls are to be placed. The bottom of the trench is lined with concrete to provide a footing 13 for the foundation. The foundation blocks 2a and 2b are then laid on the concrete base like regular or conventional blocks. The blocks are laid with the solid top 11 upwards. Once a foundation of blocks has been laid, a double-walled structure wall with, for example, a brick outer wall or brick 14 and a concrete block inner wall 15 can be built on top of the foundation wall with the outer brick skin 14 being built above the outer elongate side portions 2 of aligned contiguous blocks, and the inner concrete skin 15 being built substantially above the inner side portions of contiguous foundation blocks. Insulation 16 is provided in the cavity between the outer 14 and inner 15 walls. The top of the foundation block 1 is approximately in line with the ground 17.

The inventors found that a basic concrete mix as follows is particularly advantageous (percentages are approximate percentages by volume):

i) Pumice 50% ii) Expanded clay 20% iii) Washed sand 15% iv) High strength cement 15%

v) A strength improver additive such as liquid COLOURPLAS ULTIMA (trade mark of Oscrete).

Figures 4 to 6 illustrate in more detail (measurements in mm) the construction of three similar foundation blocks 1 for use in building foundations. Referring to figures 4c-4 4d, 5c-5d, and 6c-6d, the elongate side portions 2 each include four side portion voids 6 separated by side portion ribs 7. The side portion voids 6 each taper at a 1° taper to a solid top 11 (shown at the bottom in each of the figures) which has a minimum thickness of

20mm. The blocks each include two central voids 5 separated by a central internal rib 4 and bounded at their ends by respective end walls 3.

In the embodiment shown in figures 4a to 4d (see figure 4b), the end walls 3 are 25 mm thick, the side portion internal walls 8 and side portion external walls are each 20 mm thick, the side voids 6 are 60 mm wide and the central voids 5 are 100 mm wide. The central voids 5 are each 181.9 mm long, the end side voids 18 are each 77 mm long and the middle side voids 19 are 84.9 mm long. The block 1 is 435 mm long, 300 mm wide and 215 mm high.

In the embodiment shown in figures 5a to 5d (see figure 5b), the end walls 3 are 25 mm thick, the side portion internal walls 8 and side portion external walls are 25 mm thick, the side voids 6 are 60 mm wide and the central voids 5 are 108 mm wide. The central voids 5 are each 180 mm long, the end side voids 18 are each 77.5 mm long and the middle side voids 19 are 77.5 mm long. The block 1 is 435 mm long, 328 mm wide and 215 mm high.

In the embodiment shown in figures 6a to 6d (see figure 6b), the end walls 3 are 25 mm thick, the side portion internal walls 8 and side portion external walls are 20 mm thick, the side voids 6 are 60 mm wide and the central voids 5 are 128 mm wide. The central voids 5 are each 181.9 mm long, the end side voids 18 are each 77 mm long and the middle side voids 19 are 84.9 mm long. The block 1 is 435 mm long, 328 mm wide and 215 mm high.

Claims

1. A cuboidal foundation block (1) for use in construction, the block including a first support surface (11) for supporting a structure assembled on the block, a second laying surface (20) opposite the first support surface (11) and for laying on the floor of a foundation trench or similar, two opposing side walls (9) and two opposing end walls (3) connecting the support and laying surfaces, the block comprising two elongate block supporting side portions (2) separated from each other and each block supporting side portion (2) being configured to withstand a downward force from a block structure (15) assembled on the first support surface of the foundation block; wherein the side portions (2) are joined in parallel at each end by the opposing end walls (3) to form a cuboidal foundation block (1), the end walls configured to withstand an inward force from matter surrounding the block when the block is in use;

wherein the first support surface (11) is a continuous unbroken surface and the side portions (2) and the end walls (3) are formed integrally from concrete.

2. A foundation block according to claim 2 wherein the width of each of the elongate side portions (2) corresponds approximately to the width of a course of the blocks (15) to be built on top of the foundation block (1) and the width of the space between those elongate side portions defined by the end walls corresponds approximately to the width of the cavity or space to be provided between the walls to be built on the respective elongate side portions.

3. A foundation block according to claim 2 wherein the width of each of the elongate side portions (2) corresponds to the width of a building brick.

4. A foundation block according to any of the preceding claims wherein the width of the elongate side portions (2) is in the range 90 to 120 mm.

5. A foundation block according to any of the preceding claims wherein the width of the elongate side portions (2) is approximately 100 mm.

6. A foundation block according to any preceding claim wherein the width of the space between those elongate side portions (2) defined by the end walls corresponds approximately to the width of the wall cavity or space to be provided between a double wall comprising walls to be built on the respective elongate side portions.

7. A foundation block (1) according to any preceding claim, wherein each of the elongate side portions (2) is formed of two elongate substantially parallel side walls connected by a plurality of rib walls (7) defining at least one void.

8. A foundation block according to claim 7, wherein each of the elongate side portions (2) is formed of two elongate substantially parallel side walls connected by at least three rib walls (7) defining at least two voids.

9. A foundation block according to any preceding claim wherein the elongate side portions (2) are further joined by an internal reinforcing wall (4), parallel to the end walls;

the end walls (3) and reinforcing wall (4) together configured to withstand an inward force from surrounding matter when in use; and, wherein the side portions (2), the end walls (3) and the reinforcing wall (4) are formed integrally from concrete.

10. A foundation block according to any preceding claim, wherein the thickness of the walls (3,9) is each in the range of 15-30 mm.

11. A foundation block according to claim 10 wherein the thickness of the walls (3,9) is in the range 20-25 mm thick.

12. A foundation block according to any preceding claim wherein the block (1) comprises the following concrete mix (approximate percentages by volume):

i) pumice and expanded clay together 70% (+/-10 %) ii) washed sand 15% (+/-10 %) iii) cement 15% (+/-10 %)

13. A foundation block according to claim 12 wherein the block (1) comprises the following concrete mix (approximate percentages by volume):

i) pumice and expanded clay together 70% ii) washed sand 15% iii) cement 15%

14. A foundation block according to claim 13 wherein the pumice is approximately 50% and the expanded clay approximately 20%.

15. A one-part foundation block according to any preceding claim, and produced by compression moulding.

16. A method of building a foundation for a walled building, the method comprising the steps of:

a) providing a plurality of foundation blocks according to any of claims 1 to 15,

c) laying a wall of blocks on the portion of the support surfaces of those foundation blocks corresponding to an elongate block supporting side portion of said foundation blocks.

17. A method according to claim 16 comprising laying two separated and parallel walls of blocks to form a double-skinned wall with a cavity between the two walls, a first one of said parallel walls of blocks being laid on a first one of the two elongate block supporting portions of the contiguous foundation blocks and a second one of said parallel walls being laid on the second one of the two elongate block supporting portions of the contiguous foundation blocks.