From:
JB Maidlow [mailto:jbmaidlow@sympatico.ca]
Sent: Wednesday, July 04,
2007 10:48 PM
To: areld@bmts.com
Subject: Fw: Paisley Inn
Mr Johnson,
Recent Engineer's Report re Paisley Inn. See Below
B Maidlow
JAMES KNIGHT & ASSOCIATES
PROFESSIONAL ENGINEERS
POB 273 ST. GEORGE ONTARIO CANADA N0E 1N0
519 448 3548 FAX 519 448 4657 (cell) 905 691 6489
June 25, 2007
Mr. Burke Maidlow
42 Toronto Street
GUELPH, Ontario
N1E 3E2
Re: Structural Investigation - Northwest Wing of Paisley Inn
Paisley, Ontario
Dear Mr. Maidlow:
On May 25, 2007 the writer visited the Paisley Inn, hereinafter "the Inn", to undertake a limited structural investigation. This visit was made per your telephone request of May 15, 2007. My purpose was to inspect and assess the exposed, accessible wood structure of the Inn’s northwest wing. Subsequently structural analyses have been undertaken to assess the roof and floor structures’ suitability vis-a-vis contemporary standards.
This letter is the Report of my findings, opinions, conclusions and recommendations.
1.0 Conventions and Limitations
The Inn is located on the west side of Queen Street, which is the main north-south route through Paisley. In all the Inn is comprised of four distinct sections, as follows:
The main 3-storey section at the northeast, fronting on Queen Street and including the taller tower section.
A 2-storey section at the southeast, also fronting on Queen Street.
A single storey section at the southwest, lying immediately behind (b) preceding and having no frontage on a roadway.
A 2-storey section at the northwest, fronting on Mill Drive and lying immediately behind (a) preceding and immediately north of (c) preceding.
This investigation and this Report was concerned with the 2-storey section that is (d) only. No inference whatsoever should be drawn from this Report with respect to any other portion of the Inn.
For purposes of this Report the building’s exterior walls are assumed to lie north-south and east-west, and the roof ridge is assumed to run east-west. Therefore the rear entrance at the second floor level, which is the only exit from this wing directly to the exterior, is located in the west face of the building.
In this report:
Member dimensions shown in the format "a in. X b in." refer to the actual member size in inches.
Member dimensions shown in the format "aXb" are nominal only; the actual dimensions are usually smaller.
In (a) and (b) above, dimension "a" is the member width and dimension "b" is the member depth.
"Code" refers to the Ontario Building Code and to its various referenced standards.
This investigation included non-destructive inspection of only the exposed and accessible wood framing, followed by structural analysis of the roof and floor framing.
No other area or feature of the Inn’s northwest wing apart from these stated aspects was considered in this investigation. Hence no inference or conclusion should be drawn from this Report with respect to any other aspect of the northwest wing. Moreover, and as stated previously, no area other than the northwest wing was considered in this investigation. Hence no inference or conclusion should be drawn from this Report with respect to any other wing of the complex that is the Paisley Inn.
2.0 Description
2.1 General
The northwest wing is gable roofed, with the roof ridge running east-west. In plan this wing is approximately 35 ft. wide in the north-south direction by approximately 52 ft. long in the east-west direction. (Note that this 52 ft. length is an average length in that the northwest wing is somewhat skewed to the south with respect to its abutting the main northeast wing. The exterior dimensions along the shorter south and longer north sides are approximately 48 ft. and 56 ft., respectively.)
The roof, floors and all walls are wood framed.
The construction styles include:
Conventional wood stud and joist framing of the attic floor and the occupied floors.
Conventional rafter and purlin framing of the roof.
The exterior walls are solid masonry.
Interior partition walls at the main floor and the upper floor are wood framed with lath and plaster finishes.
2.2 Framing
2.2.1 Roof Structure
The roof framing is as follows:
The roof decking is 1 in. random width boards that are multi-span continuous over the supporting rafters of (b).
The rafters run north-south and they consist of two distinct sections. The upper section, that butts at the ridge and whose lower end is supported by the purlin of (c), is 3 in. X 4 in. The lower section, that rests on the wood plate and whose upper end is supported by the purlin of (c), is 3 in. X 5 in. There is considerable variability in rafter depth, with some being as much as an inch shallower that the dimensions quoted above.
The purlins are 3½ X 9 in. and they run east-west. There is one purlin in each face of the roof; it is located midway between the wall and the ridge. The purlins are supported by the "trusses" of (d).
The "trusses" that support the purlins are essentially heavy tied-rafters, rather than true trusses. There are four such members spaced at a minimum of 10 ft. and a maximum of 15 ft. apart. The upper chord, i.e., the rafter member itself, is 4½ in. X 8 in. The number, size and location of the ties varies from truss to truss.
2.2.2 Attic Floor
The finished ceiling below the attic is lath and plaster supported by the joists of (b) and (c).
The attic ceiling joists that span north-south from the wood plate atop the south brick wall to the north corridor wall are 2X8s spaced at 16 in. centres. Joist width varies from approximately 1¾ in. to 2 in. while depth varies from approximately 7 in. to 8 in. These joists are located at the same level as the wood plates atop the exterior brick walls.
The attic ceiling joists that span north-south from the north brick wall to the north corridor wall are 2X4s spaced at 16 in. centres. Joist width varies from approximately 1¾ in. to 2 in. while depth varies from approximately 3½ in. to 4 in. These joists are located approximately 2 ft. below the level of the wood plates that are atop the exterior brick walls. Moreover, these 2X4 attic joists are also approximately 2 ft. below the 2X8 attic joists of (b). Much of the distress within the roof and attic structure as described by Section 3.5 is directly attributable to this discrepancy in the levels of the attic joists.
2.2.3 Upper Floor Structure
The upper floor structure consists of the following.
The floor decking is 1 in. boards running east-west.
The 10 in. (nominal) deep joists run north-south and they are spaced at 16 in. centres. Depending upon the area of floor under consideration, joist width varies from 2 in. to 3 in. and joist depth varies from 9½ in. to 10 in.
Support for the floor joists is by the interior and exterior walls that run north-south, and by the wood beams of (d).
The floor beams are as follows:
At approximately 11 ft. east of the west end wall, there is an 8 in. X 9 in. beam with an overall length of approximately 22 ft. Site conditions suggest that the beam is supported mid-span by a wood column. Access was not available to confirm the column’s presence or to determine its size and nature.
At approximately 37 ft. east of the west end wall, there is an 8 in. X 9 in. beam spanning the entire 35 ft. width. The beam is supported mid-span by a wood column that is exposed in the centre of the former Dining Room. The column is 9½ X 9½ and it is decoratively turned down to a minimum diameter of approximately 6 in.
2.2.4 Main Floor Structure
The main floor structure consists of the following.
The floor decking is 1 in. boards that run east-west.
The joists are 3 in. X 10 in. sawn lumber. They run north-south and they are more or less regularly spaced at 16 in. c/c.
The joists are supported by the perimeter foundation walls and by an interior stone wall that runs east-west more or less along the centre of the building.
3.0 Inspection
3.1 General
Section 1.0 described the general conventions and limitations applicable to this Report. More specifically, significant portions of the northwest wing of the Inn are presently hidden by finishes. Also there is no in-built access to portions of the building, while other portions are presently inaccessible due to site conditions. Such hidden and/or inaccessible portions at this inspection were:
The crawl-space beneath the main floor.
The main floor itself lying west of the Dining Room.
All interior walls and ceilings are clad with lath and plaster that is intended to be retained and refurbished.
3.2 Wood Species
Samples were taken from representative structural members for laboratory determination of the wood species. They were found to be a mixture of Eastern Hemlock and Eastern White Pine, with the latter being far the more widespread. The sampled members were as follows:
Eastern White Pine - 4X9 truss chord
2X4 attic joist at north side
2X8 attic joist at south side
3X9 roof purlin
8X9 2nd floor beam
Eastern Hemlock - 2X4 stud @ attic
3X4 roof rafter
3X10 2nd floor joist
2X8 ceiling joist at attic
All structural analyses of Section 4.0 were therefore conducted with the assumption that the structural members are of the species group "North Species" as defined by CSA O86, "Engineering Design in Wood" comprising a part of the Code.
3.3 Wood Grades
Sample members were examined in situ to determine the grade vis-a-vis the NLGA Standard Grading Rules that are referenced by the Code.
In my opinion, the exposed and accessible members satisfy the requirements for No. 1 grade of the applicable size and use category. Hence No. 1 was assumed and used for all of the structural analyses of Section 4.0.
3.4 General
3.4.1 Decay was found at the frames and sills of most accessible windows and exterior doors. Local repairs and/or replacement of some window/door elements will be required. Also, when the existing doors and windows are opened and/or removed it may be expected that local decay of some wall elements may also be found in some places. Local repairs and/or replacement of those decayed elements will also be required.
3.4.2 Decay and/or missing components were found locally at the other exposed woodwork, including soffits, fascias, etc. Local repairs and/or replacement of these elements will also be required. All exposed woodwork that is to remain will require scraping and painting.
3.4.3 There are a number of conditions with the exposed brick walls that require attention and repair.
Individual bricks are locally crumbled, spalled, broken and/or otherwise failed. They are to be replaced as/where necessary.
Mortar is locally failed, softened and/or lost from the joints. Local repointing is required as/where necessary.
Much of the existing brickwork is hidden by a cementitious stone-like veneer and/or by painting. It is likely that additional local brick repairs and repointing per (a) and (b) respectively will be required once all these finishes are removed back to the native brick.
3.4.4 The brick chimney at the west end of the building requires repair of deteriorated and/or lost brick and mortar. If the chimney is to be retained the repairs will likely require it to be broken down to some level below the roof level and then be rebuilt.
3.4.5 Support for a number of main roof and upper floor members is coincident with lintels over windows in the north and south walls. Many such lintels have deflected, been crushed and/or themselves are inadequately supported. As a result several such lintels are no longer level. Local strengthening is required.
3.5 Roof
3.5.1 The roofing is asphalt shingles that are well past the end of their effective service life. The shingles are in such a poor condition that roof leaks must be occurring which, if left unchecked, will lead to decay of the roof structure. Complete reroofing is be required.
3.5.2 From the exterior there are distinct and noticeable areas of general deformation within the roof structure.
The ridge itself is not straight, as its "sags" between the west gable end and the 3-storey wing to the east.
The north eave is not straight, as the wood plate is visible outside having moved laterally to the north. This plate consists of an 8 in. X 12 in. X 8 ft. piece to the east that is butt-spliced to an 8 in. X 12 in. X 48 ft. piece to the west. The entire 8 ft. piece is more or less uniformly displaced approximately 8 in. to the north. The displacement of the 48 ft. piece is approximately 8 in. at the east end, reducing more or less linearly to virtually zero at the west gable wall. Refer also to No. 3.5.6 below.
Both roof faces appear to generally sag between the eave and the ridge.
Further to (c) there are two areas of very noticeable depression:
On the north roof face, more or less coincident with the most easterly of the four trusses.
On the south roof face, more or less coincident with the secondmost easterly of the four trusses.
3.5.3 Whilst standing within the attic, the overall impression of the roof structure is that is quite light. In other words, and based on past experience with buildings of this type and vintage, I would have expected to see larger, more numerous members, particularly in a structure in an area of such heavy snow load.
3.5.4 No evidence of decay or insect damage was observed in any of the roof or attic structural members.
3.5.5 A number of items of structural distress were observed re the wood framing:
All rafters and purlins sag to some extent. The sag of the rafters is particularly noticeable.
The 8 in. X 12 in. wood plate on the north wall is displaced. Refer to No. 3.5.2(b) above and to No. 3.5.6 that follows.
Further to (b), the birds-mouth connections at the north wall plate have opened up and pulled apart.
Three of the heavy rafter pieces are broken. All are flexural failures and all are coincident with the dapped support for the purlins:
The north half of the secondmost westerly truss.
The south half of the thirdmost westerly truss.
The north half of the fourthmost westerly truss.
3.5.6 Further to No. 3.4.3, there is significant distress of the brick at the top of the north wall. The thrust of the rafters and trusses has displaced the 8 in. X 12 in. top plate towards the north, with the result that the upper six to eight courses of brick have failed, i.e., the brick courses above the lower attic floor of No. 2.2.2. Some of the bricks have been lost to the outside; others are lying loose inside. The wood plate, and therefore the north side of the roof is presently supported on temporary wood columns and brick pilasters that bear on the sound top of the wall. The roof thrust is presently resisted by cables running across to the south wall plate.
3.6 Upper Floor
3.6.1 No evidence of decay, insect damage or distress was observed in any of the structural members.
3.6.2 Several of the framing members have been heavily drilled, notched, dapped, etc. to accommodate the various iterations of mechanical and electrical that have been installed over the years. Such drilled/dapped/notched members require local repair and strengthening.
3.7 Main Floor
3.7.1 No evidence of decay, insect damage or distress was observed in any of the structural members to which the writer was permitted access. The writer was advised that the main floor structure lying to the west of the Dining Room is essentially decayed in toto and that complete replacement is required.
3.7.2 Several of the framing members have been heavily drilled, notched, dapped, etc. to accommodate the various iterations of mechanical and electrical that have been installed over the years. Such drilled/dapped/notched members require local repair and strengthening.
4.0 Structural Analysis
4.1 General
Structural analyses have been undertaken to determine the allowable load carrying capacity of the roof and floors. All such analyses have been undertaken in accordance with the provisions and the requirements of the Code.
4.2 Loadings
Analyses have assumed the roof and floors to be subject to the Code-specified live loads in combination with the structure’s own self-weight. An allowance has been included where appropriate to account for present and future partitions.
The Code-prescribed live loads that have been assumed are as follows:
Ground snow load interpolated as 2.48 kPa (51.8 psf) from entries in the Code’s Table No. 2.5.1.1 for surrounding locations.
Rain load interpolated as 0.4 kPa (8.4 psf) from entries in the Code’s Table No. 2.5.1.1 for surrounding locations.
Balanced and unbalanced roof snow loads in view of (a) and (b) of 2.21 kPa (46.2 psf) and 2.66 kPa (55.6 psf), respectively. See also Note 1 that follows.
Live load at attic floor of 0.48 kPa (10 psf) as the attic is generally inaccessible. Refer to Note 3 that follows.
Live load at upper floor of 2.4 kPa (50 psf).
Live load at ground floor of 4.8 kPa (100 psf).
All of the loadings were considered singly and/or together, howsoever specified and required by the Code.
Notes:
The configuration of the building is such that the roof lies within the aerodynamic shade of the higher 3-storey wing to the east. This will create drift loading that will locally affect the roof framing of the east end. In light of the findings of No. 4.3.1 below, this drift loading has been ignored for purposes of this Report. However, that drift loading must be taken into account in any design of repairs and strengthening.
Wind loadings are light in comparison to the snow loads and live loads. In light of this and the findings of No. 4.3.1 below, wind loads have been ignored for purposes of this Report. However, wind loads must be taken into account in any design of repairs and strengthening.
The findings re the attic floor relate to the fact that the attic is essentially inaccessible, there is no storage loads, and the attic is not used to house HVAC or other equipment. In the event that any or all of these three conditions might be altered in the process of rehabilitation, then the results reported in No. 4.3.2 will not apply and strengthening would be required.
4.3 Findings
4.3.1 Roof
4.3.1.1 The 1 in. roof boards are adequate for strength. They will, however, deflect somewhat more under service loads than would be preferred. Excessive deflection would be manifest as a shortened shingle life. Stiffening is recommended.
4.3.1.2 All rafters are structurally inadequate. Strengthening is required.
4.3.1.3 All purlins are structurally inadequate. Strengthening is required.
4.3.1.4 All trusses are grossly inadequate structurally. Strengthening is required.
4.3.2 Attic Floor
4.3.2.1 The shorter 2X4 joists and the longer 2X8 joists are structurally adequate.
4.3.3 Upper Floor
4.3.3.1 The floor deck is adequate.
4.3.3.2 The joists where the east end abuts the 3-storey wing to the east are 3 in. X 10 in. Their span varies from approximately 9 ft. to approximately 17 ft. The joists are adequate for spans of up to 15 ft.; hence the joists within approximately 10 ft. of the north wall require strengthening.
4.3.3.3 The joists of the secondmost easterly bay are 2 in. X 9½ in. spanning approximately 13 ft. 6 in. They are not adequate; strengthening is required.
4.3.3.4 The joists of the two most westerly bays are 2 in. X 9½ in. spanning approximately 11 ft. These joists are adequate.
4.3.3.5 The 8 in. X 9 in. beams are grossly inadequate. Strengthening is required.
4.3.3.6 The exposed, turned column supporting the centre of the east beam of No. 4.3.3.5 is structurally adequate. The presence, size and adequacy of the column supporting the centre of the west beam remains to be confirmed.
4.3.4 Main Floor
4.3.4.1 Where sound and free of decay, the floor deck is adequate.
4.3.4.2 Where sound and free of decay, the 3 in. X 10 in. floor joists are not adequate.
The joists are not adequate for considerations of strength inasmuch as their allowable live load capacity is approximately 68 psf, or about 70% of the required.
The joists are not adequate for considerations of stiffness inasmuch as their allowable live load capacity is approximately 84 psf, or about 80% of the required.
Strengthening is required.
5.0 Considerations re Rehabilitation
5.1 The northwest wing of the Inn is not structurally adequate.
The roof is overstressed throughout. Local failures of wood members and supporting brick have occurred. The roof has been temporarily stabilized with cables and shoring. While this has arrested the tendency for the lateral spread at the eaves, it does nothing to relieve the basic inadequacies, all of which are essentially related to winter snow loads.
The allowable load carrying capacity of portions of the floor structures is less than the Code currently requires. Local strengthening is required.
Certain portions of the structure have suffered decay and/or distress. Again, local strengthening is required.
Depending both upon the methods that will eventually be chosen for repair, and the specifics re your intended use and occupancy, effecting the strengthening and rehabilitation will be more or less routine with some aspects being somewhat more challenging. Nevertheless, it will be the type of strengthening and rehabilitation that is done on a regular basis with buildings of this vintage and nature when being adaptively reused in compliance with modern Codes. There is nothing about the inadequacies as reported herein that would preclude the possibility of proper repair, strengthening and rehabilitation.
5.2 The northwest wing of the Inn is at risk in its present moth-balled state due to a number of reasons.
There is no positive ventilation for much of the structure.
There is obvious water infiltration through roof leaks.
There is periodic flooding in the basement.
There is no heat over the winter.
All of these conditions are conducive to decay and other deterioration. The longer the Inn remains in this condition then the greater and more rapid will be the deterioration. I therefore recommend that rehabilitation occur as soon as possible.
5.3 The wood roof structure is grossly inadequate; extensive repairs and strengthening are required. Two general repair strategies are available.
The first option is to leave the existing structure in place while designing and installing all of the repairs and strengthening that are required to achieve Code compliance. This is the repair strategy that is usually undertaken with existing buildings, as it is usually the least costly option and it preserves the heritage fabric of the building.
The second option is to demolish the entire existing roof structure above the level of the wood plates. (The wood members so removed would have significant salvage value as raw material for furniture, mill-work, and the like, either in the restored Inn or elsewhere.) Thereafter a new roof structure would be installed that would consist of a plywood/OSB cladding over conventional light trusses to be placed at 2 ft. centres.
In the specific instance of the northwest wing of the Inn it is my opinion that Option (b) is likely to be the preferred option. My reasoning is as follows:
Option (b) can be completed more quickly.
Option (b) will more readily permit the proper rebuilding of the top of the north wall, including the resetting of the sill plate to its required position.
Option (b) will by its nature include provision to laterally support the rebuilt top of the north wall. Option (a) will require some additional lateral support to be devised and installed.
Option (b) will permit the original roof profile to be reclaimed. Most of the existing deformation would remain following the work of Option (a).
The total net cost (engineering and construction) is unlikely to be significantly different for either of the two options.
5.4 Repairs and strengthening must include the rebuilding of the top of the north wall, including the re-setting and re-anchoring of the wood sill plate. This must be one of the first functions to be done. Moreover, the design of strengthening must include provision to:
resist the thrust of the rafters within the plane of the roof independently of both the wood plate and the brick wall; and
laterally support the rebuilt top of the brick wall.
5.5 The attic floor is adequate as is provided the conditions of access and/or use do not change. Notwithstanding this, the present attic structure would likely be relieved of load if the roof rehabilitation is effected by removal of the existing and replacement with new roof trusses.
5.6 The upper and ground floor structures both require some strengthening of individual members.
In the case of the inadequate joists, the most practical repair strategy will be to provide additional, new joists alongside and/or between the existing as/where required. Such installation may be from above, by removing the floor deck, or from below, by removing the ceiling, if/where present.
In the case of the inadequate beams, several repair strategies are possible, including:
Provide additional columns to reduce the span.
Engage existing partitions to reduce the span.
Provide new members alongside, whether sawn wood, LVL, Parallam or steel.
Provide new members underneath, whether sawn wood, LVL, Parallam or steel.
Combinations of two or more of (i) to (iv) inclusive.
The choice of which strategy to use for any particular beam will depend, inter alia upon such factors as cost; current level of inadequacy; available clearances under and beside the existing; existing method of beam/joist connection; intended use of floor space; proximity to existing partitions; etc.
All such repairs and strengthening are very "doable". They are not at all dissimilar to repairs and strengthening that are completed quite routinely as part of the rehabilitation of buildings of this nature to present Code requirements.
5.7 Note again that the findings and opinions herein relate solely to the northwest wing of the Inn. Any repair and rehabilitation of this wing will be most economically and efficaciously completed by including it as part of an overall scheme to reclaim all four wings of The Paisley Inn.
I trust all of this to be as you require.
If you have any questions, or if you require anything further, please telephone me at 519 448 3548.
I shall await your further direction.
Yours very truly,
James Knight, M.Sc.F., P.Eng.
07-483
James Knight, M.Sc.F.,
P.Eng.
POB 273
St. George, Ontario
N0E 1N0
Canada
Tel: 519 448-3548
Fax: 519 448-4657
Cell: 905 691-6489