CA2708378A1 - Insulated log homes - Google Patents

Abstract

A log for a log home has a plurality of pockets formed within the body of the log. The pockets are filled with foam to enhance the thermal rating of the log.

Description

3 [0001] The present invention relates to logs for use in log homes.

SUMMARY OF THE INVENTION

6 [00021 It is well known to utilize logs stacked one above another to form the wall of a house.
7 The intersection of logs at corners is accommodated through overlapping joints, either a saddle 8 splined joint or a dovetail joint by providing a connection to a post. Such construction provides 9 an aesthetically pleasing finished product and reflects the traditional values of the environment in which such houses are typically built. Such houses are formed from logs that are rough hewn to 11 shape as they are built into a wall and the gap between the logs sealed with "chinking". As an 12 alternative to the hand hewn log homes, machined logs have been utilized in the construction.
13 Machined logs have a uniform cross section and the abutting faces of the logs are machined to 14 form a seal system to inhibit the ingress of air between the logs making up the wall. Such construction offers greater thermal efficiency for the building and assists in meeting the air 16 infiltration standards of the relevant building codes.

17 [00031 A further aspect of the building code is the minimum thermal rating, commonly 18 referred to as the R value in North America or U-value in Europe, which is the reciprocal of the 19 R value of the wall. U=5.682/R, taking into account the change in units.
The R value for a log is accepted to be R 1.25 per inch and to meet a requirement for a minimum insulation value of R16 21 it would be necessary to provide 12 inch thick logs. Logs of this dimension are expensive and 22 difficult to obtain in volume and as such make it difficult to attain the minimum values required.
23 It is of course possible to increase the thermal efficiency by insulating the internal surface of the 24 wall but this detracts from the inherent aesthetic value of the log wall construction.

[0004] A number of attempts have been made to increase the thermal rating of the log wall 26 material by implementing a thermal break in the log. One of those is shown in PCT application 27 WO 96/07802 in which a plurality of longitudinal slots are cut into the body of the log so as to 28 attempt to provide the necessary thermal efficiency. It is then suggested that thin foam strips can 22007748.1 1 then be set into those cuts. However such an arrangement destroys the integrity of the log and 2 requires careful manufacture in order to ensure that the natural movement of the wood does not 3 result in degradation of the log itself. The logs are invariably machined in a green state and dry 4 over a period of time after assembly. the machining of relatively thin sections leads to the cupping and warping of the sections so that an irregular section of the log is obtained.

6 [0005] Moreover, such an arrangement also makes it difficult for the inter-engaging seal 7 profiles to be manufactured and maintained. The inter engaging profiles are tapered so as to 8 obtain a close fit between the adjacent logs. The sealing material placed between the logs is then 9 compressed as the logs are brought together. Because of the natural movement of the material of the log, an effective seal can only be obtained if the two logs are forced into contact and 11 subsequently held with the seal in a compressed state. This is typically done by using bolts that 12 extend vertically through the wall and tightened to hold the logs together.
The bolts may be 13 periodically tightened as the house dries to maintain the compressive load.
The tapered profile of 14 the sealing area therefore generates a significant lateral load when the logs are assembled in to a wall that must be resisted if the seal is to remain effective and ingress of air is to be avoided. A
16 log formed by a series of laminar sections does not have the necessary lateral strength to resist 17 the lateral loads imposed and would therefore not offer a practical solution.

18 [0006] Even if those deficiencies are ignored, practically it is not possible to insert or place 19 foam within a narrow slot of the nature described in the above application.
Rigid foam cannot be inserted due to the friction occurring between the foam and the sides of the slot, and if a 21 clearance is provided to make this possible a loose fit of the foam is obtained. If the foam is 22 injected, the narrow slots cause the foam to bridge and therefore not fully fill the slots. The 23 force of the expansion is also likely to increase the lateral loading on the thin sections, causing 24 further misalignment and deviation.

[0007] Norwegian patent application 173068 similarly describes a log arrangement with thin 26 elongate slots and sections of log and so is subject to the same deficiencies.

27 Similar deficiencies exist with the arrangements shown in U.S. Patents 4,344,263 and 3,992,838.
28 Both of these proposals require a continuous slot filled with foam and extending partially 29 through the log. As such both are susceptible to cupping of the sections of the log and movement 22007748.1 1 in a lateral direction. The Farmont proposal addresses this issue with a metal strap across the 2 groove but this not only increases the cost of the manufacture, it also makes it impractical to 3 adopt the sealing profiles necessary to obtain the air tight seal between logs.

4 [00081 It has also been proposed to laminate a log construction to obtain a thermal break by using inner and outer log panels with a plastic foam block between as shown in WO/95/30807.
6 Such a process, however, is very expensive to produce and has the risk of de-lamination between 7 the foam and the exterior panels given the lifecycle of such a building. De-lamination would 8 subject the foam core to crushing due to the weight of the balance of the logs and as such is not 9 an acceptable practice. The foam would not offer the requisite lateral strength for sealing between the logs.

11 [00091 There is therefore the need for a log construction in which the thermal rating of the 12 log may be increased without destroying the structural integrity of the log.

13 [00101 In general terms the present invention provides a log having a plurality of pockets 14 formed at spaced locations along the log. The pockets are separated by lands constituted by the material of the log that extend transversely between oppositely directed faces of the log. The 16 pockets are filled with an insulating material, typically a foam. The lands are dimensioned to 17 provide sufficient lateral rigidity to withstand forces imposed and maintain the structural 18 integrity of the log.

19 [00111 By providing discreet pockets along the length of the log, the structural integrity of the log is maintained whilst its thermal rating is increased. Sealing profiles may be machined on 21 each of the sealing faces and the terminal portions of the log may be devoid of pockets to permit 22 normal joint construction for the corners.

23 100121 In one embodiment, the pockets are blind bores extending from an upwardly directed 24 surface of the log and terminating prior to the lower surface. In another embodiment, the bores extend through the log and in a further embodiment the pockets are tapered to receive a tapered 26 plug of pre-foamed foam. Generally the bores are perpendicular to the log surfaces but they may 27 be inclined to increase the cross sectional area if preferred. In a further embodiment, the bores 22007748.1 1 extend between opposed faces of the log so when the logs are stacked, the bores are aligned and 2 provide a continuous column of foam.

[0013] Embodiments of the invention will now be describing by way of example only with 6 reference to the accompanying drawings in which, 7 [0014] Figure 1 is a schematic representation of a house having walls formed from logs.
8 [0015] Figure 2 is a view on the line of II-II of Figure 1.

9 [0016] Figure 3 is a side view of a log used in the wall of the house of Figure 1.
[0017] Figure 4 is an end view of the log of Figure 3.

11 [0018] Figure 5 is a section on the line V-V of Figure 3.
12 [0019] Figure 6 is a plan view of the log of Figure 3.

13 [0020] Figure 7 is a plan view of an alternative embodiment of log.

14 [0021] Figure 8 is a view similar to Figure 6 showing a further embodiment of log.
[0022] Figure 9 is a view similar to Figure 8 showing a further embodiment of log.

16 [0023] Figure 10 is a side view similar to Figure 3 showing an alternative configuration of 17 log.

18 [0024] Figure 11 is a section on the line XI-XI of Figure 10.

19 [0025] Figure 12 is an end view similar to Figure 4 showing the manufacture of the log of Figure 4.

21 [0026] Figure 13 is a side view of an alternative log 22 [0027] Figure 14 is an end view of the log of Figure 10 showing a method of manufacturing 23 the log of Figure 13.

24 [0028] Figure 15 is a plan view of a further alternative embodiment of plug.
22007748.1 1 [00291 Figure 16 is a perspective view of an alternative embodiment.
2 [00301 Figure 17 is an end elevation of the embodiment of Figure 16.

[00311 Referring therefore to the drawings, in Figure 1 a house 10 has side walls 12, 14 that 6 support a roof 16. The side walls 12, 14 intersect at a corner 18.

7 100321 Each of the walls 12, 14 is formed from a plurality of logs 20 that extend horizontally 8 and are stacked one above another in a vertical direction. As can be seen in Figure 2, the logs 20 9 have a pair of oppositely directed surfaces, designated an outer surface 22 and an inner surface 24. The outer surface 22 and inner surface 24 are interconnected by an upwardly directed 11 surface 26 and a downwardly directed surface 28, it being understood that the terms upper and 12 lower refers to the normal orientation of the logs 20 when assembled into a wall 12,14. The 13 upper and lower surfaces 26, 28 are milled to have complimentary profiles 30,32 such that when 14 stacked one above the other, the profile 32 of lower surface 28 is snugly received on the profile 30 of the upper surface 26. Seals may be incorporated between the tongue and groove 16 formations to provide an effective seal during the inevitable movement of the logs, as more fully 17 described in co-pending Canadian application number 2,557,364.

18 [00331 The log 20 is shown in greater detail in Figures 3 to 6 from which it will be seen that 19 it has an elongate body portion 40 with a terminal portion 42. The terminal portion 42 is provided to accommodate a joint that cooperates with a log 20 of an adjacent wall at the corner 21 18 to interlock the two wallsl2,14. As shown in Figure 3, the terminal portion 42 is provided 22 with a tail 44 that forms one-half of a dovetail joint. It will be appreciated that other 23 constructions may be utilized, such as a saddle joint.

24 [00341 The body portion 40 is formed with a plurality of pockets each defined by bores 46 that extend from the upper surface 26 toward the lower surface 28. In the embodiment of Figure 26 3, the bore 46 is of constant circular cross section and is formed by drilling from the upper 27 surface 26 toward the lower surface 28. The bores 46 are uniformly distributed along the body 28 40 and have a diameter less than the spacing between the inner and outer walls 22, 24. In a 22007748.1 1 typical embodiment as shown in Figure 6, a log 20 with a nominal spacing of eight inches 2 between the outer face 22 and inner face 24 is provided with bores 46 having a diameter of four 3 inches. The bores 46 are spaced apart on seven inch centres providing a three inch land 48 4 between each of the bores 46. With the bores 46 spaced apart on the centre line of the log 20, a nominal two inch boundary layer 49 is provided between the bore 46 and the surfaces 22, 24 6 respectively. The bore 46 terminates prior to the lower surface 28 and provides a minimum 7 thickness in the order of 1 inch.

8 [0035] The bore 46 is filled with a expanded foam plug 50 that extends up to the upper 9 surface 26 and is formed to have the same profile as the upper surface 26, as will be described below. The foam plug 50 is typically a closed cell foam such as urethane having a high thermal 11 insulation value. Typically such foams have an insulation of R6 per inch and a suitable foam is 12 available from Polyurethane Foam Systems Inc. of Waterloo, Ontario under the trade name 13 Polarfoam PF-6352-0.

14 [0036] The foam plug 50 may be formed in situ using the bore 46 as a mould.
In this case, the lower face of the bore 46 provides a closed vessel to permit pouring of the liquid foam.

16 [0037] With the configuration of pockets shown in Figure 6, the insulation value of the log is 17 increased from 1.03 per inch, that is RI 0.4 to an average value of 20.6.
This increased thermal 18 rating is achieved without affecting the structural integrity or the ability of the log to provide an 19 efficient sealing system in the wall. It should be noted that the end portions 42 are maintained to permit the corner joints to be formed out of solid material with the body 40 offering a higher 21 thermal efficiency. The provision of the end face of the bore 46 provides sufficient transverse 22 strength to inhibit splitting of the log 20 when the profiles 30,32 are engaged.

23 [0038] The provision of the bores 46 is also beneficial to the production of the logs 20. By 24 pre-drilling the logs 20 with the bores 46 they may be stored upside down to prevent water collecting in the bores 46. The provision of the bores 46 decreases the drying time of the log 20 26 significantly from the typical twelve months, allowing the inventory of log 20 to be reduced.
27 Moreover the whole structure also has the effect of stress relieving the log 20 and thereby 28 reducing the surface cracking that is typically present on the surfaces 22, 24. Such surface 29 cracking does not reduce the overall strength of the log 20 but it is aesthetically displeasing. The 22007748.1 1 cracking that does occur will take place on the upper surface 26 between the pockets, thereby 2 enhancing the thermal efficiency of the lands 48 without adversely affecting the structural 3 strength.

4 [0039] The logs 20 as shown in the embodiments of Figures 1 through 6 may be produced by initially machining the log blank and drilling the bores 46. The log 20 is then left to dry until the 6 required moisture content is attained, after which the foam plug 50 is formed in each of the bores 7 46. The plug material is mixed in a liquid form and placed into bores 46 where it forms in situ.
8 Thereafter, as shown in figure 12, the upper and lower surfaces 26, 28 are machined to the 9 requisite profile and the tails 44 machined to provide the required joint.
The foam plug 50 is supported on all sides by the walls of the bore 46 and therefore milling of the upper face 26 can 11 be accomplished with the foam core in situ. With the upper and lower surfaces 26, 28 formed, 12 the log can then be assembled into a wall having the requisite thermal rating.

13 [0040] It will be appreciated that the extent of the body 40 may vary from log to log to 14 accommodate features of the building 10 such as doorways and windows. It that event, the end portions 42 may be left solid to accommodate joints or other fixtures, but logs extending across 16 such openings can have the foam plugs 50. The configuration of the bores 46 may vary 17 according to different requirements. For example, in Figure 7, the nominal width of the log 20 is 18 8 inches and bores 46 are 4 inch diameter. The bores 46 are arranged on 8 inch centres providing 19 a 4 inch land 48 and a two inch boundary layer 49. With this configuration an average thermal rating of R 19.4 is obtained.

21 [0041] In general terms, the lands 48 have a dimension along the longitudinal axis of the log, 22 referred to as the thickness of the land, that is sufficient to withstand the lateral forces imposed 23 on the log. The lands 48 provide a continuous web between the boundary layers 49, which, when 24 combined with the dimensions of the bores 46, inhibit spreading of the inner and outer surfaces 22,24. Typically, the thickness of the land 48 is greater than the minimum boundary layer 49.
26 The thickness of the land 49 is also less than the longitudinal dimension of the bore 46.
27 Preferably, the bores 46 have an aspect ratio, that is the ratio of the longitudinal dimension to the 28 lateral dimension, that is not greater than 2:1 so that the lateral or transverse dimension of the 22007748.1 1 bore 46 is at least 50% of the longitudinal dimension. The dimensions may be adjusted to suit the 2 logs involved and attain the average thermal rating required by the building code.

3 100421 The bores 46 may also be manufactured with varying cross sections as shown in 4 Figures 8 and 9. In the embodiment of Figure 8, the bores 46 are formed with a square cross section provided by a chain mortiser. In the arrangement of Figure 8, a nominal eight inch log is 6 formed with the bores 46 with four inch sides and on a seven inch spacing.
This provides a land 7 48 of three inches but the volume of foam provided in the bore 46 is increased compared to a 8 circular cross section. As such, an increase in the order of 25% of the cross sectional area of the 9 foam is obtained to increase the average thermal rating to a value of R=23.4.

[00431 In the embodiment of Figure 9, the bore 46 are formed from a pair of overlapping 11 circular bores 46 to present an oval cross section. The bores 46 have a 5 by a 2 1/2 dimensions 12 and the land 48 between the holes is in the order of 3 inches. This provides an R value in the 13 order of R 30Ø

14 [0044] As shown on Table 1 below, a number of different configurations may be used to obtain the desired increase in R-value with relatively few pockets. In the first configuration 16 shown in row 1, circular bores of 3 inch radius extend through the log and are spaced apart by a 17 land of 21.5 inch. Surprisingly, the R value of the log is increased from 10.4 to 16.3, which is 18 sufficient to meet the Canadian building code requirements. This increase is attained with a 19 relatively small number of pockets which maintains the integrity of the log.

[00451 Similar results are shown in row 2 where square pockets are spaced apart 24 inches to 21 get a similar increase in R value. With overlapping circular bores of 3 inch diameter, as shown 22 in row 3, a land of 35 inches may be used and with an elongated oval, as shown in row 4, a 23 spacing of 45 inches is possible whilst maintaining an R-value above 16.

24 100461 An array of smaller diameter staggered pockets, as shown in row 5, may also be used to attain the required value.

22007748.1 1 Table I
'Insulated' Log R-value Calculator Log Width (in) 8 R-log (per in) 1.3 R-value (log only) 10.4 R-foam (per in) 7 % foam % log R-value U-value U-value I BTURx/s tUd F W/ m/C
Top View of log 1. s (in) = 21.5 13% 87% 16.3 0.061 0.349 O O O r (in) = 3 Top View of log 2. S s (in) = 24 13% 87% 16.2 0.062 0.349 x (in) 6.5 (in) 5.5 F-I El El EJ-:-Ov y X
Top View of log 3. s (in) = 36 13% 87% 16.3 0.061 0.348 r r(in) 3 I~-I c (in) = 3 C
Top View of log 4. ~ C= s ~)~(~) r s (in) = 46 13% 87% 16.2 0.062 0.350 H N--N r (in) = 3 c (in) = 5 C
6 Top View of log F r s (in) = 2.6 13% 87% 16.4 0.061 0.347 O O O O OO 0 0 0 0 000 0 0 0 0 0 0 0 0 0 0 O O 00000 r (in) = 1 Minimum value for Canada is R = 12 2 Maximum value in the UK is U = 0.35 W/sq m/C

4 [00471 From the above, it will be seen that a variety of configurations may be adopted to obtain the requisite thermal rating, and that where a particular rating is required, the ratio of foam 6 filled pockets to original log may be adjusted to provide this. As shown below in Table 2, 7 reducing the pocket cross section and the spacing enables the same thermal rating to be achieved 8 as the equivalent configuration in table A, thereby illustrating the versatility of the arrangement 9 when meeting particular building requirements, such as interconnecting walls and services.
22007748.1 1 Table 2 'Insulated' Loa R-value Calculator Log Width (in) 6 R-log (per in) 1.3 R-value (log only) 7.8 R-foam (per in) 7 %foam % log R-value U-value U-value BTU/hr/s fVde F W/s m/C
Top View of log 1. s (in) = 4.6 25% 75% 16.2 0.062 0.350 O O O r (in) = 2 Top View of 1-2 . S s (in) = 3 25% 75% 16.4 0.061 0.347 0 EJ ED---i~ " y (in) = 3 X
Top View of log 3. s (in) = 9 25% 75% 16.2 0.062 0.350 cr r (In) 2 C (in) = 4 C
Top View of log 4. r s (in) = 11.25 25% 75% 16.3 0.062 0.349 r (in) 2 (in) = 4 C
Top View of log S r s (in) = O 25% 75% 16.2 0.062 0.350 000000000 O O 0000 r (in) = 0.625 Minimum value for Canada is R = 12 2 Maximum value in the UK is U = 0.35 W/sq m/C

4 [00481 In each of the above embodiments, the bore 46 is of uniform cross section and 5 terminates prior to the lower surface 28. The bores 46 may of course extend through the log, 6 provided provision is made for inserting the foam. When the bore extends fully through the log, 7 as illustrated in figure 12, the foam may be machined on both the upper and lower faces.
8 Moreover, when the logs are stacked in a wall, the bores 46 are vertically aligned to provided a 9 continuous vertical column of foam in the wall.

[00491 It will also be appreciated that the cross sectional area of the bore 46 may be 11 increased by inclining the axis of the bore 46. In the embodiment shown in Figure 10 and 11, the 12 bore 46 is formed with a tapered cross section and extends between the opposite faces of the log 13 20. The tapered cross section permits pre-formed plugs 50 that are also tapered to be inserted 14 into the bores 46 where a tight fit is ensured by virtue of the taper. This arrangement permits the advantages of the increased thermal rating to be obtained without requiring onsite storage of 16 foaming materials and related material handling concerns. With the arrangement shown in 17 Figure 10 and 11, the plug may be inserted, secured within the bore 46 and the upper and lower 18 surfaces 26, 28 machined to provide the finished log 20.

22007748.1 1 100501 In an alternative arrangement as shown in Figures 13 and 14, the tapered plug 50 is 2 preformed with the profile of the upper and lower surfaces at respective ends of the plug 50. The 3 plugs 50 may then be inserted into the pre-bored log 20 with the profiles at opposite ends of the 4 plug 50 matching those of the surfaces 26,28. Such an arrangement permits the log to be assembled in situ where this is preferable.

6 [00511 It will be appreciated of course that the arrangement shown in Figure 13 and 14 may 7 also be applied to a bore 46 of uniform cross section allowing through bores 46 to be formed in 8 the log and the subsequent installation of cylindrical plugs 50. Such an arrangement would 9 require a sleeved press to insert the plugs but would also permit the use of a cylindrical extrusion cut to length prior to insertion rather than the in situ foaming as described above.

11 [00521 To facilitate insertion of preformed plugs, the arrangement shown in Figure 15 may 12 be used. As shown in Figure 15, the plug 50 is formed as two part cylindrical portions, 50a, 50b.
13 Each portion 50a, 50b is slightly less than one half the cross section of the bore 46 providing a 14 gap 60 between the portions 50a, 50b when inserted.

[00531 The portions 50a, 50b are held in situ by a wedging action in the gap 60. In one 16 embodiment, the gap 60 is filled with expandable foam which expands to hold the portions 50a, 17 50b, and the relatively small gap enables the foam to be supplied by pressurised containers if on 18 site installation is required.

19 [00541 It will be seen therefore that the provision of the pockets in the log 20 provides an opportunity to increase the thermal rating without adversely affecting the integrity of the log.
21 The lands between each of the bores ensure that the inner and outer faces are secured at all times 22 to one another and also provides sufficient strength to avoid crushing of the log. The provision 23 of the foam also allows the sealed profiles to be machined in the plug together with the balance 24 of the sealing faces and for the log to maintain the integrity of the end portions for conventional joining techniques.

26 [00551 A further embodiment of log is shown in Figures 16 and 17, in which like 27 components will be described with like reference numerals with a suffix "a"
added for clarity. In 28 the embodiment of Figure 16, logs 20a are formed as described above to have an elongated body 22007748.1 I portion 40a and bores 46a. The bores 46a are filled with an expanded foam plug 50a, either in 2 situ or as preformed plugs, that extend along the oppositely directed upper and lower surfaces 3 26a, 28a.

4 [0056] The upper surface 26a and lower surface 20a are configured to provide opposed, abutting ledges 70 and an internal cavity 72 when the logs 20a are assembled.
One of the ledges 6 70, on the lower surface 28a in the embodiment of Figure 16, is formed with a groove 74 to 7 receive a seal 76 to seal against the oppositely directed ledge 70 of the adjacent log. The seal 76 8 may be a butyl rubber or foam seal impregnated with asphalt and is effective to seal between the 9 abutting ledges 70.

[0057] The cavity 72 is formed between the ledges 70 in the centre portion of the upper 11 surface 26a and lower surface 28a. The upper surface 26a is formed with an upstanding shoulder 12 78 inboard of the ledges 70 and a recessed channel 80 that extends downwardly to intersect the 13 foam plug 50a.

14 [0058] The lower surface 28 is similarly formed with a central recess 82 that extends to the plug 50a and is spaced from the shoulders 78.

16 [0059] It will be appreciated that the shoulders 78, channel 80 and recess 82 extend the 17 length of the log as a uniform cross section and may terminate prior to the end sections to allow 18 the conventional joint to be manufactured.

19 [0060] A series of lateral holes 84 are machined from one side of the log 20a so as to intersect the channel 80 at regular intervals. The holes 84 are spaced along the length of the log 21 and are of sufficient diameter to allow a foaming wand to be inserted into the hole 84.

22 [0061] To assemble a wall using the embodiment of Figure 16, the logs 20a incorporating the 23 foam plugs 50a are stacked one above the other with the seals 76 forming an air tight seal 24 between abutting ledges 70. With the wall assembled, foam is injected through the holes 84 so as to fill the cavity 72. The injection occurs along the length of the log at each of the holes 84 26 until the cavity 72 is filled. The seals 76 effectively inhibit the egress of foam from the cavity so 27 that the foam is contained in the cavity along the length of the log.
Thereafter, wooden plugs 86 28 are inserted into the holes 84 to present a aesthetically pleasing finish to the logs.

22007748.1 1 100621 The foam utilized in the preferred embodiment is a foamed polyurethane product such 2 as the that sold under the name "Insulator" available from NCFI
Polyurethanes of Airy NC and 3 provides adherence to the wood of the log 20a to inhibit separation of the logs 20a. The preferred 4 foam is a two component, one to one by volume self adhering seamless high efficiency rigid polyurethane foam adhesive system. The product identified as NCFI 11-018 has been found 6 suitable, The foam provides insulative properties and adheres to the logs 20a to connect the two 7 opposed faced. The foam injected into the channel 72 therefore not only acts as a thermal 8 insulation between the logs 20a but also acts to secure the logs 20a to one another to provide an 9 integral wall. Separation of the logs 20a as they dry is therefore inhibited and ingress of air between the logs 20a inhibited.

11 [00631 The building may be assembled in a conventional manner by stacking the logs 20a 12 one above the other with the shoulders 78 locating the logs laterally. Tie bolts may be inserted 13 through the logs in a conventional manner to provide an initial setting of the logs 20a.

14 [00641 Once assembled, the foam is then injected into the cavity 72 to fill the cavity and secure the logs to one another.

16 [00651 Once foamed, the plugs are inserted and the building may be finished. Thereafter, the 17 relative movement between adjacent logs 20a due to changes in humidity is inhibited by the 18 adhesion of the foam with the cavity.

19 [00661 Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without 21 departing from the spirit and scope of the invention as outlined in the claims appended hereto.
22 The entire disclosures of all references recited above are incorporated herein by reference.
22007748.1

Claims (54)

1) A log having an elongate body with a pair of oppositely directed wall faces extending between a pair of oppositely directed sealing faces, a plurality of pockets extending from one of said sealing faces through said body to the other of said sealing faces, said pockets being and uniformly spaced along said body, said pockets being separated from one another by lands extending between said wall faces-said pockets and lands being dimensioned relative to one another to preserve structural integrity of said log and maintain relative spacing of said wall faces.

2) A log according to claim 1 wherein terminal portions of said body are devoid of pockets.

3) A log according to claim 1 or 2 wherein said sealing face has sealing formations formed thereon for engagement with a complimentary formation on an adjacent log.

4) A log according to any one of claims 1 to 3 wherein said land between pockets has a dimension measured along the longitudinal axis less than the corresponding dimension of said pocket but greater than the spacing of said wall faces from a periphery of said pocket.

5) A log according to any one of claims 1 to 4 wherein said pockets are of substantially constant cross section.

6) A log according to any one of claims 1 to 4 wherein said pockets taper.

7) A log according to any one of claims 1 to 6 wherein said pockets are distributed and sized to provide an increased in thermal rating of said log to at least R16 when said pockets are filled with foam.

8) A log according to any one of claims 1 to 7 wherein said pockets are filled with foam.

9) A log according to claim 8 wherein said foam is preformed and inserted in to said pockets as plugs.

10) A log according to claim 9 wherein a pair of plugs is inserted in a pocket and retained by a wedge spreading said plugs.

11) A log according to claim 9 wherein said plug and pocket are tapered and said plug is retained by interference between said pocket and said plug.

12) A log according to any one of claims 1 to 11 wherein said pocket has a dimension between said wall faces of 50% of the spacing between said wall faces.

13) A log according to any one of claims 1 to 12 wherein said pockets are circular.

14) A log according to any one of claims I to 12 wherein said pockets are square.

15) A log according to any one of claims 1 to 12 wherein said pockets are oval.

16) A building including at least one log according to any one of claims 1 to 16.

17) A building according to claim 16 wherein intersecting walls of said building are formed with logs according to any one of claims 1 to 16 and wherein terminal portions of said logs are devoid of pockets.

18) A building according to claim 17 wherein said terminal portions are formed as interlocking joints.

19) A method of forming a log having a pair of oppositely directed sealing faces, said method comprising the steps of forming a plurality of pockets in said log at uniformly spaced intervals along said body, said pockets extending from one of said sealing faces through said log to the other of said sealing faces said pockets being spaced apart greater than the dimension of said pocket along the axis of said long to provide a land extending between said pockets and filling said pockets with insulating foam.

20) A method according to claim 19 including the step of machining formations on said one face after said foam is formed in said pockets.

21) A method according to claim 19 or 20 wherein said foam is preformed and inserted in to said bores.

22) A method according to claim 21 wherein said pocket is tapered and said foam is preformed with a complementary taper.

23) A method according to claim 21 where said foam is inserted in said pocket as a pair of portions and retained in said pocket by a wedge acting between said portions.

24) A method according to claim 23 wherein said wedge is a foam inserted between said portions.

25) A log having an elongate body with a pair of oppositely directed wall faces extending between a pair of oppositely directed sealing faces, a plurality of pockets extending from one of said sealing faces into said body and uniformly spaced along said body, said pockets being separated from one another by lands extending continuously between said wall faces each of said pockets having a dimension measured in a direction transverse of said walls that is not less than 50% of the spacing between said walls, said pockets and lands being dimensioned relative to one another to preserve the structural integrity of said log and to maintain relative spacing of said wall faces.

26) A log according to claim 25 wherein said lands have a dimension measured along the longitudinal axis of said log less than the corresponding dimension of said pocket but greater than the spacing of said wall faces from a periphery of said pocket.

27) A log according to claim 25 or 26 wherein said pockets have a combined volume that is at least 20% of the volume of said log.

28) A log according to any one of claims 25 to 27 wherein said pockets have a transverse dimension at least 50% of the longitudinal dimension.

29) A log according to any one of claims 25 to 28 wherein said sealing face has sealing formations formed thereon for engagement with a complimentary formation on an adjacent log.

30) A log according to any one of claims 25 to 29 wherein said pockets extend between said sealing faces.

31) A log according to any one of claims 25 to 30 wherein said pockets are of substantially constant cross section.

32) A log according to any one of claims 25 to 30 wherein said pockets taper.

33) A log according to any one of claims 25 to 32 wherein said pockets are distributed and sized to provide an increased thermal rating of said log to at least R16 when said pockets are filled with foam.

34) A log according to any one of claims 25 to 33 wherein said pockets are billed with foam.

35) A log according to claim 34 wherein said foam is preformed and inserted in to said pockets as plugs.

36) A log according to claim 35 wherein a pair of plugs is inserted in a pocket and retained by a wedge spreading said plugs.

37) A log according to claim 35 wherein said plug and pocket are tapered and said plug is retained by interference between said pocket and said plug.

38) A log according to any one of claims 25 to 37 wherein terminal portions of said body are devoid of pockets.

39) A log according to any one of claims 25 to 38 wherein said pockets are circular.

40) A log according to any one of claims 25 to 38 wherein said pockets are square.

41) A log according to any one of claims 25 to 38 wherein said pockets are oval.

42) A building including at least one log according to any one of claims 25 to 41.

43) A building according to claim 42 wherein intersecting walls of said building are formed with logs according to any one of claims 25 to 41 and wherein terminal portions of said logs are devoid of pockets.

44) A building according to claim 43 wherein said terminal portions are formed as interlocking joints.

45) A method of forming a log having a pair of oppositely directed sealing faces and a pair of oppositely directed wall faces, said method comprising the steps of forming a plurality of pockets in said log to extend not less than 50% of the distance between said wall faces and extending from one of said sealing faces to the other of said sealing faces with a land extending between said pockets and filling said pockets with insulating foam.

46) A method according to claim 45 wherein said foam is formed in situ.

47) A method according to any one of claims 45 or 46 including the step of machining formations on one of said sealing faces after said foam is formed in said pockets.

48) A method according to claim 45 wherein said foam is preformed and inserted in to said bores.

49) A method according to claim 48 wherein said pocket is tapered and said foam is preformed with a compounding taper.

50) A method according to claim 48 where said foam is inserted in said pocket as a pair of portions and retained in said pocket by a wedge acting between said portions.

51) A method according to claim 50 wherein said wedge is a foam inserted between said portions.

52) A method of forming a wall of a log building by stacking logs vertically one above another with abutting faces cooperating to define an internal cavity and injecting a foam within said cavity after assembly of said logs to connect said logs to one another.

53) A method according to claim 52 wherein pockets are formed in said logs extending from one of said abutting faces prior to assembly of said logs into a wall.

54) A method according to claim 53 wherein foam is inserted in said pockets prior to assembly of said logs into a wall.