GB2408287A - Reusable guide frame for building base - Google Patents

Abstract

A method of constructing a base of a building comprising the steps of assembling component parts and fixing these together in a releasable manner to provide a substantially rigid guide frame of the shape and size of the desired base area and positioning the assembled frame in the desired location to define the periphery of the desired base area. Concrete 42 is then poured around the frame to a level indicated by lower guide means of the frame to provide footing before placing a flexible, substantially impermeable plastic sheet 46 to cover the base area defined within the frame and draping the plastic sheet over the frame itself and then casting a concrete slap 48 on top of the sheet 46 up to a level indicated by upper guide means of the frame. The frame is subsequently removed and disassembled. Also disclosed is a guide frame for use in such a method.

Description

METHOD AND REUSABLE GUIDE FRAME FOR BUILDING EXTENSION

BASE

This invention concerns a method of constructing a base of a building or of a building extension by making use of a guide frame assembled from component parts.

The invention has been made in the context of conservatory construction where the mounting of prefabricated, precision engineered building parts onto a traditionally constructed base necessitates accuracy in the dimensions of the latter if problems are not to arise in fitting the prefabricated parts. However, the invention is applicable to any type of building or building extension, and the time, labour and cost saving resulting from the invention would make if advantageous, in particular, in constructing the base for a wide range of building extensions.

Traditionally, the first stage in constructing a conservatory extension is to mark out a desired base area using pegs and lines, which takes time and skill to achieve accuracy. A trench is then dug to a depth required for footing concrete and brickwork, guides are set and the concrete is poured in and levelled. That is all that can be done on the first day as the concrete footing has then to set. On the second day brickwork, which will constitute part of an outer skin of a cavity wall, is laid on the concrete footing up to a height required for a concrete slab which is to be laid within the base area. On the third day, when that brickwork is set, the enclosed base area is prepared and shattering of a thickness corresponding to a desired cavity is placed inside the brickwork. A plastics sheet, providing a damp proofing membrane, is then spread over, and concrete for the slab is poured in a levelled up to the height of the containing brickwork. On the fourth day, with the concrete slab set, the shattering can be removed and the brickwork can be completed by continuing the outer skin up to the level required (generally referred to as the dwarf wall height as it is usually fairly low, often less than lm) and laying the inner skin upon the edge margin of the slab. Only on the fifth day can the fitting of the prefabricated conservatory frame element begin.

The above scheme of work is extremely inefficient in terms of skilled labour time and equipment. A skilled bricklayer has to visit the site twice, on alternate days. The first visit will probably only involve a couple of hours work, so time is wasted travelling between sites. Also concrete has to be mixed on two separate, alternate days. This will probably involve bringing a mixer to the site, with wasted travelling time between sites or non- operating time, if it is kept there.

An object of the invention is to reduce the time, and therefore the cost, of constructing a base of a building or a building extension, such as a conservatory. Another object is to reduce the skill and time required for accurate marking out and construction of such a building base, and make it easier reliably to achieve the necessary accuracy. This is a particular requirement when prefabricated parts are to be fitted to the base.

With these objects in view, the present invention provides, as a first aspect, a method of constructing a base of a building or of a building extension comprising the steps of assembling component parts and fixing these together in a releasable manner to provide a substantially rigid guide frame of a shape and size of a desired base area, positioning the assembled frame in a desired location upon prepared ground to define the periphery of the desired base area, pouring concrete around the frame to a level indicated by lower guide means of the frame to provide footing, placing a flexible, substantially impermeable plastics sheet to cover the base area defined within the frame and drape over the frame itself, and casting a concrete slab on top of that sheet within the base area defined by the guide frame up to a level indicated by upper guide means of the frame, and subsequently removing and disassembling the frame.

Shuttering, for example in the conventional form of wooden planks, may be fitted to the inside of the assembled guide frame either at the outset or after the footing concrete has been poured. Alternatively, the components of the frame may include portions, permanently attached, which serve as shattering. The shattering provides a barrier to confine the concrete slab as it is cast.

According to a further aspect of the invention, a substantially rigid guide frame is provided for use in the aforesaid method, which frame comprises a plurality of component parts which are releasably and adjustably connected to each other and include upper guide means in the form of a plurality of upper guide elements and lower guide means in the form of a plurality of lower guide elements.

Yet a further aspect of the invention is a kit of parts which are adapted to be assembled together in an adjustablemanner and to be releasably connected to provide the aforesaid guide frame.

By making use of this guide frame in the method of the invention it is possible to pour the concrete for the footing and cast the concrete slab on the same day because the frame itself, optionally with the addition of shattering fitted to it, will confine the concrete slab, without the need for brickwork to perform this function.

Once the concrete is set, on the following day, both courses of brickwork for the outer and inner skins can be laid on the same day. The guide frame then advantageously serves as a guide for the positioning of the first course of brickwork of the outer skin, which may be laid just outwardly of the frame, upon the footing concrete, before the frame is removed and disassembled.

The frame can usefully define a required gap between the inner and outer skins of brickwork.

Thus, by making use of the guide frame of the invention, in effect as a temporary jig, and of the method proposed by the invention it is possible to construct a base for a conservatory or other building or building extension in two days instead of the customary four days.

This in itself saves on costs as work can proceed more rapidly. Moreover, as both steps involving concrete mixing and pouring can be done in the same day, and all the brick laying can be done on the same day, waste of skilled labour time and equipment downtime can be avoided and further savings made.

A prior proposal for casting a concrete slab within a rigid frame to provide a base for building construction is disclosed in GB 2020723. However, in that case only one stage of concrete pouring has been proposed so that concrete penetrates beneath the frame at the S same time as the slab is formed, and the frame is maintained in position as an integral part of the slab after the concrete is set.

The present invention differs in that the guide frame proposed here is intended to be removed after the slab is cast, optionally disassembled to component parts, and reused later at another site. Moreover, the component parts of the frame are adjustably and releasably connected so that frames of different sizes and shape can be constructed to meet the desired base dimensions at any given site.

The invention will be described further, by way of example, by reference to the accompanying drawings, in which: Figs. I to 3 are perspective views of three different upper guide rail elements of a practical embodiment of a kit of parts for constructing a guide frame in accordance with the invention; Fig. 4 is a perspective view, to an enlarged scale compared to Figs. 1 to 3, of a lower guide element, although it may also service as another type of upper guide element; Fig. 5 is a diagrammatic, part sectional sketch showing how a practical embodiment of the guide frame is used in the method of the invention; Fig. 6 is a reduced scale perspective view of one embodiment of an assembled guide frame; Fig. 7 is a similar view of another embodiment of an assembled guide frame; and Fig. 8 is a similar view of a third embodiment of an assembled guide frame.

Preferred practical embodiments of the guide frame of the invention are constructed from various combinations of frame elements. Three fairly typical examples of fully assembled, substantially rigid guide frames are shown in Figs. 6, 7 and 8.

Fig. 6 shows a frame used to construct a substantially rectangular base for a conservatory or building extension. It comprises an upper guide rail 10 supported by lower guide elements in the form of upright connectors 20 and elongate cross pieces 22. The upper guide rail l O is made up of two wall brackets 12, two right angled corner pieces 14, as shown more clearly in Fig. 1, one standard elongate element 22', which is identical to the cross piece 22 and is shown separately and more clearly in Fig. 4, and four elongate extension pieces 16.

All of these parts are made of box section steel. The wall brackets 12, corner pieces 14 and standard elongate elements/crosspieces 22t, 22 are made of 50mm box section, and are provided with screw clamps 18 of conventional type, although these are not shown in Figs. 1 to 4. The extension pieces 16, which are not separately illustrated, are made of 40mm box section so as to be a sliding fit in the ends of the aforesaid three types of components, enabling telescopic adjustment prior to clamping by the screw clamps 18 so as to obtain any desired length of the sides of the upper rail 10. The extension pieces 16 may be provided in a variety of lengths, e.g. lm, 2m, 3m long.

The corner pieces 14 and the standard elongate elements/crosspieces 22t, 22 have 25mm box section channels 24 fixed to their outer faces, which are intended to face outwardly of the frame in use. These channels 24 are also provided with screw clamps 18, and their purpose, as clearly illustrated, is to permit adjustable attachment of the upright connectors 20 which are of 20mm box section.

The corner pieces 14 have dependent tabs 26, four in the illustrated example of Figs. 1 and 6, which have apertures to allow shattering in the form of plywood planks to be bolted on.

Apertures (not shown) may also be provided at spaced intervals along the extension pieces 16, at least along an inner face of same, also to allow attachment of shattering. Such shattering will be bolted to the inside of the frame so as to extend around the entire frame and to a depth from flush with the upper surface of the upper rail 10 to below the lower element cross pieces 22, one function of which is to serve as abutments for the shattering.

Fig. 7 shows a frame used to construct a base for a conservatory, often referred to as Victorian in style, which is polygonal in shape, having four corners of 135 . The same reference numerals are used for parts which correspond to those in Fig. 6. Instead of right angle corner pieces (14), four 135 corner pieces 34, as shown more clearly in Fig. 2, are used in the upper guide rail 10. These are connected to each other by respective extension pieces 16. Wall brackets 1 1 also form part of the upper rail 10, but compared to those in S Fig. 6, they are of smaller cross-section (e.g. 40mm) so as to fit adjustably into the ends of the corner pieces 34. In other respects, the construction of this frame is the same as in Fig. 6.

Fig. 8 shows a hybrid shape of frame which including most of the aforementioned types of components, which need not be described again, and also a reverse type of right-angled corner piece 36, which is shown separately and more clearly in Fig. 3. This is also of 50mm box section steel, but has its channels 24 for attachment of the upright connectors 20 and its tabs 26 for attachment of shattering on the opposite sides compared to the conventional right-angled corner piece 14 of Fig. 1.

To explain how these guide frames are employed in the method of invention, reference is made to Fig. 5.

At the site of construction the relevant area of ground is cleared and a guide frame is constructed from the various component parts available, as already described with reference to Figs. 1 to 4 and 6 to 8, to the desired shape of the base of the conservatory or other building extension. This frame is placed in position with the wall brackets 11 or 12 offered up to the existing wall and is used to mark the position for footing using line paint or similar. The frame is then put to one side and a trench 40 is dug to the required depth for footing. The area enclosed by the trench is where a concrete slab 48 will be cast and this is also dug to the required depth, not as low as the footing, and prepared by laying stone or gravel and consolidation, as necessary or appropriate.

The guide frame is then positioned in the footing trench 40, the wall brackets 1 1 or 12 are fixed to the existing wall and the upright connectors 20 are adjusted relative to the upper rail 10 to ensure that the frame is level and square. In this respect, the upper surface of the rail 10 should be set to the desired level for the concrete slab 48. The lower cross-pieces 22, which extend parallel to the upper rail 10, should be set to the level required for the footing concrete. The footing concrete 42 is then poured in to this level.

S At this point, if not already bolted on, plywood planks 44 providing the shattering should be fitted to the inside of the frame by way of the tabs 26 and optionally directly to extension pieces 16, flush with the top of the rail 10 and bedded into the footing concrete 42. The slab area is then sanded and a substantially impermeable plastics sheet 46 is spread over, as a damp proofing membrane. This also drapes over the shattering 44 and the frame. The concrete for the slab 48 is then poured in up to the top of the frame, and the latter being substantially rigid and flat is used for tamping and levelling off the slab.

As the frame is of substantially rigid construction, the shattering is firmly supported against the top rail 10 and the lower cross pieces 22 and does not deform under the weight of the concrete. Thus, sinking and bulging at the edges of the concrete slab 48 is avoided.

It should be noted that it is not necessary to wait for the footing concrete 42 to set before the plastics sheet 46 is placed and the slab concrete 48 poured over that. Therefore, they can both be accomplished on the same day.

One advantage of using the frame is the accurate positioning of same relative to the footing, which means that the edge of the slab concrete 48 reliably extends down to the footing concrete 42. This is good practice and desirable as a damp proof measure.

The day after the concrete has been poured, when it is set, an outer skin of brickwork, indicated at 50 in Fig. 5, can be laid upon the footing concrete 42, at a narrow spacing from the frame. The frame can be used to mark the position for this brickwork. The frame itself is suitably chosen to have a section width corresponding to that of a standard cavity in a double skinned wall. The frame can then be removed, taken apart if desired, and cleaned ready for re-use elsewhere. Either before or after the frame is removed, at least on course of an inner skin of brickwork, as indicated at 52 in Fig. 5, can be laid upon the edge of the concrete slab 48.

As will be readily understood by anyone familiar with building construction, the above described component parts of the kit can be put together in a large number of different ways to produce a wide variety of different guide frame shapes and sizes. Moreover, the configurations, material and dimensions of the individual component parts may vary in other embodiments within the scope of the invention. In particular, a box section configuration is not essential, although it is preferred for strength and rigidity. Also, some component parts, most likely corner pieces and/or standard elongate elements intended as upper rail elements may have, instead of tabs, extension web portions, integrally formed or permanently attached, which serve as shattering and/or for attachment of further shattering of conventional type. The wall bracket elements will of course be omitted where the frame is complete in itself and not attached to an existing wall. The sequence of operations and the time scale involved in base construction using the frame may also be varied to meet the requirements of site and workers.

Claims (21)

1. A method of constructing a base of a building or of a building extension comprising the steps of assembling component parts and fixing these together in a releasable manner to provide a substantially rigid guide frame of a shape and size of a desired base area, positioning the assembled frame in a desired location upon prepared ground to define the periphery of the desired base area, pouring concrete around the frame to a level indicated by lower guide means of the frame to provide footing, placing a flexible, substantially impermeable plastics sheet to cover the base area defined within the frame and drape over the frame itself, and casting a concrete slab on top of that sheet within the base area defined by the guide frame up to a level indicated by upper guide means of the frame, and subsequently removing and disassembling the frame.

2. A method as claimed in claim I wherein shattering strips are fitted to the inside of the assembled frame.

3. A method as claimed in claim 2 wherein the shattering strips are fitted after the footing concrete has been poured.

4. A method as claimed in claim 2 or 3 wherein the shattering strips are bedded in the footing concrete.

5. A method as claimed in any preceding claim wherein the upper guide means of the frame is used as an abutment in tamping and levelling the concrete slab.

6. A method as claimed in any preceding claim wherein, once the footing concrete has set, at least one course of brickwork is laid outside the guide frame, upon the footing concrete, before the guide frame is removed and disassembled.

7. A substantially rigid guide frame for use in the method claimed in any preceding claim comprising a plurality of component parts which are releasably and adjustably connected to each other and include upper guide means in the form of a plurality of upper guide elements and lower guide means in the form of a plurality of lower S guide elements.

8. A guide frame as claimed in claim 7 wherein the upper guide elements are releasably and adjustably connected to each other and the lower guide elements are releasably and adjustably connected to the upper guide elements.

9. A guide frame as claimed in claim 7 or 8 wherein the upper guide elements are connected to each other so as to provide an upper guide rail.

10. A guide frame as claimed in any of claims 7, 8 or 9 wherein at least some of the upper guide elements are in the form of hollow box section elements.

A guide frame as claimed in claim 10 wherein respective upper guide elements are slidingly adjustable relative to adjacent upper guide elements by fitting inside or over each other.

12. A guide frame as claimed in claim 9 wherein the lower guide elements include elongate elements which extend substantially parallel to the upper guide rail.

13. A guide frame as claimed in any of claims 7 to 12 wherein at least some of the lower guide elements are in the form of hollow box section elements.

14. A guide frame as claimed in any of claims 7 to 13 wherein the upper guide elements include substantially right angled corner elements.

IS. A guide frame as claimed in any of claims 7 to 14 wherein the upper guide elements include angled corner elements having portions which extend at approximately 135 to each other.

16. A guide frame as claimed in any of claims 7 to 15 wherein at least some of the upper guide elements have means for attachment of shattering strips.

17. A guide frame as claimed in any of claims 7 to 16 wherein at least some of the upper guide elements have shutter portions permanently attached.

18. A kit of parts adapted to be assembled together in an adjustable manner, and to be releasably connected to provide a guide frame as claimed in any of claims 7 to 17.

19. A kit of parts as claimed in claim 18 and including a plurality of upper guide I S elements, namely angled corner elements and elongate extension elements, and a plurality of lower guide elements.

20. A method of constructing a base of a building or of a building extension substantially as hereinbefore described with reference to Fig. 5 of the accompanying drawings.

21. A guide frame for use in the method claimed in any of claims I to 6 substantially as hereinbefore described with reference to and as illustrated by any of Figs. 6 to 8 of the accompanying drawings.