IE84562B1 - A timber-frame panel - Google Patents

Description

The invention relates to a timber-frame panel, particularly but not exclusively to a prefabricated timber-frame wall panel.

Two main methods of wall construction are generally used for the construction of housing, offices, shops, etc. in the UK: masonry construction and timber-frame construction. In the former, bricks or blocks of masonry are used to construct walls which carry the load imposed by the structure itself and additional loads imposed thereon by external forces such as snow loading, wind loading, etc. In timber-frame construction, a timber-frame is constructed to carry the majority of the weight of the structure and loads imposed thereon, although facings of brickwork. tiles, rendering or other suitable materials can be used to cover the timber framework. However, the majority of the loads concerned are carried by the timber-frame and not by the facing.

Prefabricated panels are commonly used in timber-frame construction. The panels generally consist of a substantially rectangular frame having a height of approximately one storey of a building (approximately 2.4m) and a width which, where possible, is made a multiple of 0.6m. This is necessary because vertical studs are required to be located at 0.6m intervals within the wall to accommodate the fixing of internal wall facing material such as plasterboard sheets, whilst also supporting vertical imposed loads. The panel will therefore usually consist of generally horizontal top and bottom members, two upright side members and two or more further upright members usually spaced at intervals of 0.6m between the upright side members.

A panel consisting purely of the members described above and fixed by nails would have very little in—plane (racking) resistance and would be prone to racking or sideways distortion. Also, forces applied to the panel substantially perpendicular to the plane thereof would result in distortion and buckling of the upright members. It is therefore common practice to apply sheathing to one side of the panel primarily to provide resistance to racking but also to prevent lateral instability of the studs acting as beams under wind loads normal to the panel. This increases the panel's ability to carry in—plane and out—of—p|ane loading. However, the application of sheathing, which is typically formed from plywood or similar wood-based materials, increases the overall weight of the panel and also adds considerably to the material cost thereof.

Furthermore, the labour costs involved in manufacturing a completed panel with sheathing are substantially higher than the cost of producing an unsheathed panel.

Furthermore, a sheathed panel requires the inclusion of a vapour control layer to prevent harmful condensation effects. The vapour control layer usually consists of a sheet of plastics material which is awkward to position and is easily punctured which adds to the difficulties of manufacture and transportation.

An unsheathed panel requires no such vapour control layer.

It has long been recognised that it would be desirable to produce a timber-frame panel which does not require sheathing. However, to provide the required strength, the joints of the frame itself require to be strengthened to a significant extent.

Various proposals for strengthening the joints have been made, but all require elaborate manufacturing or construction methods and do not substantially reduce the overall cost of the timber-frame panel.

It is an object of the present invention to provide a timber-frame panel which is sufficiently strong to obviate the need for sheathing and which can be manufactured in a simple and cost effective manner.

The present invention provides a panel as set out in claim 1. The invention also provides a method of constructing a timber-frame building as set out in claim 9 and a building comprising a panel according to the invention as set out in claim 12. Further improvements and advantageous features are set out in the subsidiary claims.

The invention provides a panel whose timber members are connected together by means of nail plates. It has been discovered that the use of suitably disposed nail plates to connect the timber members together can provide sufficient in-plane strength to resist racking whilst maintaining the ability of the panel to support vertical loads. Also, the strength of the joints, particularly in combination with the provision of transverse timber members, is sufficient to prevent lateral instability of the upright members when forces are applied to the panel perpendicular to the plane thereof.

The need for sheathing is thereby avoided, substantially reducing the cost and overall weight of the panel and obviating the need to spend time applying the sheathing or the vapour control layer during the manufacture thereof. The nail plates are also applied to the joints of the timber-frame only from the planar faces thereof. Insertion of screws, nails, dowels etc. within the plane of the panel is not required. The timber can therefore be manufactured relatively easily by means of a commonly available automatic pressing machine with reduced labour costs and increased speed.

Embodiments of the invention will now be described with reference to the accompanying drawings, wherein: Figure 1 is an elevation view of a panel which does not form part of the present invention; Figure 2 is an elevation view of an alternative panel which does not form part of the present invention; and Figure 3 is an elevation view of an embodiment of the present invention utilised in either panels shown in Figure 1 or 2.

Figure 1 illustrates a timber-frame wall panel. The wall panel 10 comprises horizontal upper and lower members 12, 14 and upright side members 16, 18. Upright members 20, 22 are positioned between the upright side members 16, 18 at regular spacings of substantially 0.6m. Transverse strengthening members 24, 25, 26 extend between the upright members 16 and 20, between the upright members 20 and 22 and between the upright members 18 and 22 respectively.

Each member 12-26 is connected to at least one other member by means of nail plates 28. For the avoidance of doubt, nail plates are substantially planar plates of metal out of which have been pressed a plurality of nail-like projections such that the projections extend substantially perpendicular to the plane of the plate itself.

Commonly, the projections extend over substantially the entire area of the plate and are arranged in rows.

One nail plate 28 is provided on either face of the panel 10 at each joint. At each corner joint. i.e. at each joint between an upright member 16, 18 and one of the top and bottom members 12, 14 an enlarged plate 28 is provided. This provides additional strength and stability to the pane|’s corner joints.

The panel 10 illustrated in Figure 1 has sufficient strength and stiffness due to the presence of the nail plates 28 to avoid the need for the provision of sheathing. The panel 10 will not rack unduly under normal in-plane loading and the members 12-26 are joined together in a simple and easily achieved manner. The overall cost of manufacturing the illustrated frame is estimated at around 70% of the cost of the present standard sheathed frame.

In Figure 2, a panel 30 is illustrated which comprises top and bottom members 32, 34 and upright side members 36, 38. Upright members 40, 42 are provided spaced between the side members 36, 38 at 0.6m intervals.

Inclined bracing members 44a, 44b, 44c extend between the junction of the top and upright members 32, 38 and the upright member 42, between the upright members 42 and 40, and between the upright member 40 and the junction between the bottom member 34 and the upright member 36. The bracing members 44a, 44b, 440 are aligned so as to be collinear with one another. The inclined bracing members 44a, 44b, 44c extend along a diagonal of the frame 30. This bracing member effectively triangulates the frame 30 so as to prevent racking as a result of in-plane forces being applied to the panel. Depending upon the direction of the in-plane force acting on the panel 30, the bracing members 44a, 44b, 440 can operate under tension or under compression. Also, further inclined bracing members can be provided; for example, parallel but spaced from the bracing members 44a, 44b, 440, or inclined in the opposite direction, i.e. extending along a line joining the top left and bottom right corners of the frame as seen in Figure 2 or parallel thereto. Where an elongate panel is provided having a width of greater than three or four upright member spacings, a plurality of diagonal bracing members can be arranged within the frame.

These diagonals can be arranged substantially parallel or inclined in the opposite direction, though preferably at substantially the same angle to the horizontal.

As described in connection with Figure 1, each member 32-44c is connected to at least one other member by means of nail plates 46. the presence of the nail plates 46 further increases the strength and stiffness of the panel 30, both in the in-plane direction and the out-of-plane direction. At the junction of the inclined members 44a, 44b, 44c with the upright members 40, 42, different arrangements can be provided.

As illustrated at the junction with the upright member 40, an elongate rectangular nail plate 46 extending in the general direction of the inclined members 44b, 44c can be provided. A corresponding nail plate 46 will also be provided on the reverse face of the panel 30. However, in order to improve stability and strength still further, a wider nail plate 46a can be provided as illustrated at the junction with the upright member 42. In this arrangement, the nail plate 46a is still generally rectangular but it is arranged such that it comes into contact with a greater length of the upright member 42. The arrangement illustrated has the advantage that no potentially hazardous corners project beyond the timber members and the joint between the upright member 42 and the inclined bracing members 44a, 44b is exceptionally strong and stiff.

When a panel 10, 30 as illustrated in either of Figures 1 and 2 is to be used in a construction, it is essential that the panel 10, 30 is securely anchored to the foundation. Commonly, timber-frame panels have been secured to foundations merely by nailing. It has been found advantageous to use field splice plates located at least at either end of the bottom member 14, 34 to secure the timber-frame panel , 30 to the foundation. Ideally, the field splice plate which would be used is of considerable size (for example, 0.15m x 0.3m) and have nail projections located in substantially half of the area of the field splice plate. These nail projections are used to secure the connector to the panel 10,30 during prefabrication and the lower half of the field splice plate, which contains a plurality of holes, will then be nailed to the foundation or sole plate fixed thereto during erection on-site.

Figure 3 illustrates timber-frame panel 50 according to the present invention. The panel 50 essentially comprises a top member 52, a bottom member 54 and upright members 56, 58. In this embodiment, the top member 52 and bottom member 54 extend beyond the upright members 56, 58 and additional upright members 60 are provided so as to render the overall shape of the frame generally rectangular.

However, the presence of the upright members 60 and extensions of the bottom member 54 are of little structural significance and they can be omitted altogether.

This arrangement differs dramatically from known arrangements because substantial side areas previously needed to prevent racking are no longer necessary. This means that windows positioned in the new unsheathed panels can be placed closer to one another or to corners of buildings. If the horizontal extent of the wall to each side of the window permits, the side pier can be triangulated within the height of the window by the addition of diagonal 60c and horizontals 60a, 60b.

A transverse member 62 extends substantially horizontal between the upright members 56, 58. Upright members 4 extend between the horizontal member 62 and the bottom member 54 at regular intervals of substantially 0.6m. Inclined bracing members 66 are then located between the upright members 56, 58 and the upright members 64 to provide triangulation of the panel 50.

An opening 68 is located between the upright members 56, 58 and above the horizontal member 62. The opening 68 is suitable for receiving a window frame.

Above the opening 68, a second horizontal member 70 is provided and upright members 72 are located between the second horizontal member 70 and the upper member 52 at regular spacings of substantially 0.6m between the upright members 56, 58. Inclined bracing members (not shown) can replace the upright members 72 if required.

Each of the members forming the frame 50 is joined to at least one other member by means of a nail plate as described above. The presence of the triangulating bracing members 66 and the nail plates 74 gives the panel 50 sufficient in—plane strength and stiffness for sheathing to be rendered unnecessary.

The above panels have been directed to panels which are of a standard width of substantially 1.8m in the case of Figures 1 and 2 or 3.0m in the case of Figure 3.

However, it will be appreciated that, in some cases, prefabricated panels of greater length are desirable and panels of any practical length or height can be produced.

When inclined bracing members are provided, the bracing members can be inclined in either direction and at any desired angle. Preferred angles of inclination are between 35° and 75° but are most effective at around 52°. Also, cross bracing can be introduced and inclined bracing members can also be arranged such that their horizontal extents overlap.

The panels described above can also be enhanced by the addition of rigid insulation.

The rigid insulation can be solid board material nailed to the outside of the panel; alternatively, oversized pieces of deformable insulation can be provided and forcibly introduced into the voids between the panels members so as to be retained by friction. A further alternative would be to introduce a foamed insulation material by spraying which cures rapidly into a rigid insulation.

Providing a rigid insulation provides a solid background to the breather membrane which may be required on the outer face of the timber-frame panel, thereby affording the membrane some protection from damage.

A panel as described above can be used in the following manner in the construction of a building. Firstly the panel 10, 30, 50 is manufactured according to the desired specifications. The manufacture can take place at a location remote from the site of construction of the building. The panel 10. 30, 50 is then transported to the site of construction and positioned in place. Field splice plates as described above are used to secure the bottom member 14, 34, 54 of the panel 10, 30, 50 to the foundations of the building to hold the panel in place. Additional panels are similarly located and fixed together as required. An outer facing or veneer of brick, tiles or other suitable material is then applied in a known manner.

Claims (1)

1. CLAIMS A panel for use in the construction of a timber-frame building, comprising a plurality of timber members connected together to form a substantially rectangular frame having a plurality of upright members spaced-apart from one another at a distance of substantially 0.6m or less, wherein the timber members are connected together by means of nail plates such that the addition of sheathing is rendered unnecessary, and wherein at least one inclined bracing member is provided inside the frame, the bracing member or members extending over only part of the height of the panel, and the panel incorporates an opening for accommodating a window, the opening being located above the bracing member or members and additional strengthening members being located within the frame above the opening. A panel as claimed in claim 1, wherein the bracing member or members extend over no more than half of the height of the panel. A panel as claimed in claim 1 or 2, wherein the additional strengthening members comprise a transverse member connected to the frame by a plurality of upwardly extending members. A panel as claimed in claim 3, wherein the strengthening members are connected to one another and to the frame by means of nail plates. A panel as claimed in any one of the preceding claims, wherein the angle of inclination of the or each bracing member with respect to the horizontal is between 35° and 75°. A panel as claimed in claim 5, wherein the angle of inclination of the or each bracing member with respect to the horizontal is substantially 52°. A panel as claimed in any one of the preceding claims, wherein connectors are provided at the lower region of the frame for connecting the panel to supporting means, the connector comprising a field splice plate. A panel for use in the construction of a timber-frame building substantially as hereinbefore described with reference to the embodiments shown in