GB2299828A

GB2299828A - Repairing or constructing timber beams

Info

Publication number: GB2299828A
Application number: GB9507612A
Authority: GB
Inventors: David Gordon Smedley
Original assignee: ROTAFIX
Current assignee: ROTAFIX
Priority date: 1995-04-12
Filing date: 1995-04-12
Publication date: 1996-10-16
Anticipated expiration: 2015-04-12
Also published as: GB9507612D0; GB2299828B

Abstract

A component 22 for the construction or repair of a timber beam 10 comprises an elongated body member 24 and at least one elongated connecting member 26, one end of the connecting member being anchored in the body member and the other end projecting axially from the body member. Preferably the body member incorporates a plurality of bores, in each of which is anchored one or more connecting members. The component is used to repair a timber beam by removing a damaged section of the beam, forming a recess in the remaining portion of the beam, engaging the connecting member with the recess and securing same in position to connect the repair component to the beam.

Description

Construction and Repair of Tiber Components The present invention concerns the construction and repair of timber components, and in particular although not exclusively of timber beams, columns and rafters. The term "beam" is used herein to denote all such components.

Timber beams in buildings are susceptible to rotting, decay and insect attack, which is commonly concentrated at one or more ends of the beam only. In certain circumstances, it may be possible and economic to replace a timber in its entirety. However, in larger properties where the timber is heavily loaded, this is not possible. Moreover, in the case of ornate ceilings and buildings of historical interest it may be necessary that repair be carried out with minimum disruption to existing fabric. The repair should also be visually unobtrusive.

According to the invention there is provided a component for the construction or repair of a timber beam comprising an elongated body member and at least one elongated connecting member, one end of the connecting member being anchored in the body member and the other end projecting axially from the body member.

Preferably the connecting member is anchored in a blind bore extending into the body member from an end thereof. The connecting member preferably comprises a rod.

The body member may comprise timber or laminated timber. The body member may be treated with a preservative. The body member may be stress graded, and the grading may be visibly indicated on the body member.

The body member may incorporate a single bore in which is anchored a connecting member of a relatively larqe cross-sectional area with respect to the bc e.

Alternatively, the body member may incorporate a single bore in which is anchored a plurality of connecting members, each of a relatively small cross-sectional area with respect to the bore. As a yet further alternative, the body member may incorporate a plurality of bores, in each of which is anchored one or more connecting members.

The connecting member may be formed from a reinforced resin, such as a reinforced epoxy resin, or a reinforced polyester resin. The resin may be glass fibre reinforced poester or epoxy resin, or epoxy reinforced polyester resin. The fibres may be un@-directionally orientatrd. I h e rod may OOp F I S C 8 0% b weight of grass and 20% by weight of resign.

The connecting member is preferably anchored in the body member by securing means which may comprise a polymeric resin. The resin may advantageously be an epoxy resin, a polyester resin, a polyurethane resin system or a phenolic resin.

According to the invention there is also provided a method of constructing a timber beam, the method comprising providing a plurality of beam components, at least one of which has a body member and an axially projecting connecting member, forming recess means in at least one other of said components, engaging the connecting member with said recess means and securing same in position to connect the components together.

According to the invention there is also provided a method of repairing a timber beam, the method comprising removing a damaged section of the beam; providing a repair component having a body portion and an axially projecting connecting member, forming recess means in the remaining portion of the beam, engaging said connecting member with said recess means and securing same in position to connect the repair component to the beam.

The repair component may be of larger length than the removed damaged section of the beam in which case the method includes reducing the size of the body member of the repair component by removing a portion from the end opposite to said connecting member.

The method may also include reducing the cross-section of the body member to correspond substantially to the cross-section of the beam.

Said recess means may comprise a slot opening to a side face and to the free end of the beam such that the connecting member of the repair component may be moved laterally into said slot and the body substantially aligned with the beam, the connecting member being secured in said slot by filling the slot around the rod with a bonding composition.

Preferably said slot is formed in the face of the beam which is uppermost. The bonding composition may comprise a phenolic resin, which may be an epoxy resin, a polyester resin, a polyurethane resin system or a phenolic resin.

The method further comprises providing support for the beam and for the repair component whilst repair is carried out.

The method may further comprise the application of means for camouflaging the repair. For example, a stain may be applied to areas of the bonding composition which remain visible after the repair has been completed.

According to the invention there is also provided a kit for the repair of a timber beam comprising at least one repair component as referred to above and a resin composition for bonding the component to a beam to be repaired.

Advantageously a plurality of selectively usable repair components are provided each having a cross-section corresponding to a standard cross-section of commercially-available timber beam.

An embodiment of the invention will now be described for the purposes of illustration only with reference to the accompanying diagrammatic drawings in which:- Fig. 1 is a side view of one end of a timber floor joist; Fig. 2 is a side view corresponding to Fig. 1 of the joist part way through a repair operation; Fig. 3 is an end view of the joist of Fig. 2; Fig. 4 is a side view of a repair module; Fig. 5 is a side view of the joist at a subsequent stage of the repair; and Fig. 6 is an end view of Fig. 5.

Referring to Fig. 1, there is shown part of a timber floor joist 10 supported in recess 11 in a wall 12 of a building. The end 14 of the joist 10 is decayed, for example due to rotting or insect attack, as indicated by cross hatching in Fig. 1.

To repair the joist 10, there is firstly provided appropriate load bearing support (not shown) for the joist at position A. The damaged section 14 is then removed by sawing as indicated by the broken line 15 in Fig. 1. A slot 16 is cut into the exposed end 10a of the joist 10. The length L of the slot 16 is dependent upon the cross-sectional area and the free span of the joist 10, and can readily be determined by those skilled in the art. In the example shown in Fig. 2, the slot 16 is open to the upper surface 18 of the joist, but not to the lower surface 20 thereof. Thus, as can readily be seen from Fig. 3, the part of the joist surrounding the slot has a generally U-shaped cross-section.

Alternatively, the slot may be open at both the upper and lower surfaces 18, 20 of the joist 10 or could extend from side to side.

A repair module 22 for the repair of the joist 10 is illustrated in Fig. 4. The module 22 comprises a body 24 which in the present example is formed from natural timber. Alternatively, the body 24 may be produced from glue laminated timber. The body 24 has a cross-section corresponding to that of the joist 10.

Two vertically spaced connecting rods 26 project from one end 24a of the module 24. The remainder of each rod 26 is embedded within the timber body 24 by being located within a blind bore (not shown) and secured in position during manufacture of the component 22 by means of an appropriate resin, such as a two part epoxy resin adapted for compatibility with timber.

At the repair site, once the decayed area of the joist 10 has been cut away, the end 24b of the component 22 opposite to that from which the rods 26 project may be cut so that the body 24 of the component is equal in length to the previously removed part of the joist 10.

The component 22 is then positioned in end-to-end relationship with the exposed end of the joist 10 as shown in Fig. 5, the projecting parts of the rods 26 being moved into the slot 16 from above. The component 22 is supported in this position by a suitable support (not shown). It will be appreciated that the positions of the joist 10 and rods 26 are shown diagrammatically in the drawing. In practice, the rods will usually be secured at the lowest possible position within the beam.

The component 22 and the joist 10 are then secured together by filling the space within the slot 16 around the rods 26 with a resin composition, which may be a two part epoxy resin similar to that used to secure the rods during manufacture of the component 22. Once the connection is complete and the resin set, any appropriate finishing operations may be carried out. In particular, if any parts of the resin used to complete the connection are visible, an appropriate stain may be applied. However by cutting the slot 16 into the beam from above, no resin will be visible when the beam is viewed from below and hence no staining will be required in the illustrated embodiment.

It is envisaged repair components or modules may be produced in a selection of cross-sections corresponding to conventional building timber sizes, and in a selection of lengths. Appropriate modules may thus be selected for timber joinery replacement in domestic dwellings as well as for use in larger properties. If it is required to refurbish a timber beam of a nonstandard cross-section, the next largest cross-section of repair component can be employed and cut to size on site. Likewise the length of component to be used is selected to equal or exceed the length removed from the beam, the component being shortened to the desired length where required. The repair components or modules may also be stress graded and marked appropriately to enable the component appropriate to a particular repair to be readily identified and selected.

There is thus described a convenient method of making an unobtrusive repair. Modifications may be made within the scope of the invention. For example the number and diameter of the connecting rods may be varied, and they may be arranged in any appropriate configuration within the body. The rods may be made from any other appropriate material, for example timber, plastics or metal and may be of other than circular cross-section. Where the rods are made of a glass-fibre-reinforced resin, the relative proportions of glass and resin may vary from that described.

Alternative means of anchoring the rods in the body may also be employed. The body of the connecting component may be natural timber or may be of a glue laminated timber construction. The body may be tanalised or treated with a boron timber treatment liquid to prevent dry rot, wet rot and beetle attack.

The modules may also be used to produce a new beam, or to extend an existing beam. Connecting rods may be provided to extend axially from both ends of a module, whereby to enable replacement of a central section of a beam or the construction of a long beam from two shorter sections.

Whilst endeavouring in the foregoing Specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to nd/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

claims

1. A component for the construction or repair of a timber beam comprising an elongated body member and at least one elongated connecting member, one end of the connecting member being anchored in the body member and the other end projecting axially from the body member.

2. A component according to claim 1 wherein said connecting member is anchored in a blind bore extending into the body member from an end thereof.

3. A component according to claim 1 or 2 wherein said body member incorporates a single bore in which is anchored a connecting member of a relatively large cross-sectional area with respect to that of the bore.

4. A component according to claim 1 or 2 wherein said body member incorporates a single bore in which is anchored a plurality of connecting members, each of a relatively small cross-sectional area with respect to that of the bore.

3. A component according to claim 1 or 2 wherein said body member incorporates a plurality of bores, in each of which is anchored one or more connecting members.

6. A component according to any preceding claim wherein said connecting member is formed from a reinforced synthetic resin.

7. A component according to claim 6 wherein said resin is selected from epoxy resin and polyester resin.

8. A component according to claim 6 or 7 wherein said resin is reinforced by glass fibres.

9. A component according to claim 8 wherein said glass fibres are uni directionally orientated.

10. A component according to claim 8 or 9 wherein said reinforcing member comprises 80% by weight of glass and 20% by weight of resin.

11. A component according to any preceding claim wherein said connecting member is of metal construction.

12. A component according to any preceding claim wherein said connecting member is anchored in said body member by securing means.

13. A component according to claim 12 wherein said securing means comprises a polymeric resin.

14. A component according to claim 13 wherein said resin is selected from epoxy resin, polyester resin, polyurethane resin and phenolic resin.

15. A component according to any preceding claim wherein the connecting member comprises a rod.

16. A component according to any preceding claim wherein said body member comprises timber.

17. A component according to any preceding claim wherein said body member is formed from laminated timber.

18. A component according to any preceding claim wherein said body member is treated with a preservative.

19. A component according to any preceding claim wherein said body member is stress graded.

20. A component according to claim 19 wherein said stress grading is visibly indicated on said body member.

21. A component for the construction or repair of a timber beam substantially as hereinbefore described with reference to the accompanying drawings.

22. A timber beam incorporating at least one component according to any of claims 1 to 21.

23. A method of constructing a timber beam, the method comprising providing a plurality of beam components, at least one of which has a body member and an axially projecting connecting member, forming recess means in at least one other of said components, engaging the connecting member with said recess means and securing same in position to connect the components together.

24. A method of repairing a timber beam, the method comprising removing a damaged section of the beam, providing a repair component having a body portion and an axially projecting connecting member, forming recess means in the remaining portion of the beam, engaging said connecting member with said recess means and securing same in position to connect the repair component to the beam.

25. A method according to claim 24 wherein said repair component is of greater length than the removed damaged section of the beam, the method including the step of reducing the size of the body member of the repair component by removing a portion from the end opposite to said connecting member.

26. A method according to claim 24 or 25 in which said repair component is of greater cross-sectional size than the beam to be repaired, the method including the step of reducing the cross-section of the body member to correspond substantially to the cross-section of the beam.

27. A method according to any of claims 24 to 26 wherein said recess means comprises a slot opening to a side face and to the free end of the beam such that the connecting member of the repair component may be moved laterally into said slot and the body substantially aligned with the beam, the connecting member being secured in said slot by filling the slot around the rod with a bonding composition.

28. A method according to claim 27 wherein said slot is formed in the face of the beam which is uppermost.

29. A method according to claim 27 wherein said slot extends through the beam from top to bottom.

30. A method according to claim 27 wherein said slot extends through the beam from side to side.

31. A method according to any of claims 27 to 31 wherein said bonding composition is selected from epoxy resin, polyester resin, polyurethane resin and phenolic resin.

32. A method according to any of claims 24 to 31 including providing support for the beam and for the repair component whilst repair is carried out.

33. A method according to any of claims 24 to 32 including the application of means for camouflaging the repair.

34. A method according to claim 33 wherein camouflaging is effected by application of a stain to areas of the bonding composition which remain visible after the repair has been completed.

35. A kit of parts for the repair of a timber beam comprising an elongated body member having an elongated connecting member anchored in and projecting axially from one end of the body member, and a resin composition for bonding the component to a beam to be repaired.

36. A kit of parts according to claim 35 including a plurality of selectively useable repair components each having a cross-section corresponding to a standard cross-section of commercially-available timber beam.

37. A kit of parts for the repair of a timber beam substantially as hereinbefore described with reference to the accompanying drawings.

38. A method of repairing a timber beam comprising providing a plurality of repair components each having an elongated body member including an elongated connecting member anchored in and projecting axially from one end of the body member, the body members being of a variety of predetermined lengths and cross-sectional sizes, removing a damaged section of the beam, forming a recess in the remaining portion of the beam, selecting a repair component equal to or greater in length and cross-section than the damaged section of the beam, reducing the length and cross-sectional size of the repair component where necessary to correspond to the damaged section of the beam, engaging said connecting member in said recess, and securing same in position to connect the repair component to the beam.

39. A method of repairing a timber beam substantially as hereinbefore described.

40. A timber beam repaired by the method of any of claims 24 to 34 or claim 38.

41. Any novel subject matter or combination including novel subject matter disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.