Ste-anne-des-pays-bas Church

Transcription

1 Ste-anne-des-pays-bas Church Exterior wall siding assessment Type of Document Final Project Number Prepared By: Jean-Philippe Foisy, AANB Reviewed By: Stephen Skinner, AANB exp Architects Inc. 602 Rothesay Avenue Saint John, NB E2H 2H1 Canada Date Submitted July 4 th, 2012

2

3 Table of Contents Ste-anne-des-pays-bas Church Legal Notification...i Table of Contents...ii 1 Introduction Intrusive investigations Investigation on East façade (right hand side) Investigation on North façade (left hand side) Upper Wall Lower Wall Investigation on North façade (above side entrance) Investigation on North façade (right hand side) Investigation on South façade (left hand side) Investigation on South façade (above side entrance) Investigation on South façade (above foundation wall) Investigation on East façade (left hand side) Findings Recommendations and opinion of probable cost ii

4 Ste-anne-des-pays-bas Church 1 Introduction The services of exp Architects Inc. were retained by the Saint-anne-des-pays-bas Church to investigate the existing cape cod wood siding condition. It was noticed that the exterior cladding is experiencing premature deterioration. Jean-Philippe Foisy, architect from exp, met on June 6, 2012 with Church representatives (Antoine and Gerry) to discuss the issues and have a cursory visual review of the exterior cladding in question. As-built construction drawings and specifications were handed to exp as a reference for identification of the wall assembly components. Aside from one leak in the north facade side entrance through the roof to the exterior space beneath preceding the lateral north entrance, no leaks were reported. The Church representatives showed exp the condition of the exterior wall on the North façade above the foundation level by removing the bottom approximately 8 horizontal siding boards. The removal of the siding revealed deteriorated building paper and rotted OSB sheathing. In was agreed at this point that destruction investigation would be required to obtain a better appreciation of the existing condition of the wall assembly components. Therefore, exp has hired on behalf of the church Simpson Building Contractor s to supply lifting equipment (zoom boom), an operator and a carpenter to make openings in the exterior cladding (intrusive investigations). After the investigations, the openings were sealed by using the same cladding materials. 2 Intrusive investigations On June 19, 2012 Jean-Philippe Foisy / architect, Cheryl Thomas / technologist and Stephen Skinner / architect, all from exp, were on-site with Simpson Building Contractor's for the intrusive investigation stage of the process. Exp directed the contractor to make openings in the exterior siding of approximately 1 sq.ft. in specific locations for each main surface of exterior cladding. The openings were made in order to reveal the concealed building components behind the siding for visual review by exp. The intent was to penetrate the wall assembly until we found dry and sound material. The exterior siding is Cape Cod horizontal (diagonally applied) rabbet bevel profile. Figure 0 Siding profile 1

5 Ste-anne-des-pays-bas Church For the reader s reference, the following is a key plan indicating the four main facades which we used to indicate the location of the openings. West facade North facade South facade East facade Figure 1 Building and site establishing façades nomenclature 2.1 Investigation on East façade (right hand side) Two openings were conducted on the right hand side of the East façade. Siding boards and the building paper were removed. Figure 2 East façade showing two openings in the diagonal siding 2

6 Ste-anne-des-pays-bas Church Figure 3 Close up on upper opening Figure 4 Close up on lower opening Observations The building paper and the exterior OSB sheathing were sound and dry. Wood strapping was present. We can see on figure 3 that additional small pieces of strapping were added. These were needed because the siding was not consistently cut at the vertical strapping so additional strapping was required to nail / support the end of the siding. These added pieces often had only one nail making them loose. Board overlap is minimal (figure 5), in other locations nonexistent (figures 9 and 10). Presence of moisture deterioration on the strapping was present at most locations where the strapping ran horizontally (diagonally) at the junction of the wall and roof. Figure 5 Board overlap is minimal Figure 6 Warping / nail away from board edge Comments The presence of small pieces of strapping (figure 3) seems to indicate that the contractor tried to minimize waste by not cutting the boards on the strapping pattern. Figure 6 indicates a nail away from the edge creating less support for the board therefore creating opportunity for warping. Board overlap is key for water tightness. A weak overlap creates opportunity for water penetration. 3

7 Ste-anne-des-pays-bas Church 2.2 Investigation on North façade (left hand side) Two openings were conducted on the left hand side of the North façade. Siding boards and building paper were removed. Figure 7 North facade, Left hand side Upper wall Figure 8 North façade (upper exterior wall below roof line) Observations Building paper and sheathing appeared dry. Wood strapping was not present on the projecting wing wall. Board overlap was nonexistent (figures 9 and 10). 4

8 Ste-anne-des-pays-bas Church Figures 9 and 10 In this location, no board overlap Comments The absence of strapping to allow draining and adequate venting of the cavity behind the cladding is likely the cause of the damage identified below (see point 2.2.2). Again, the board overlap is inadequate as demonstrated by figures 9 and Lower wall Figure 11 and 12 Exposed sheathing and exposed woods studs and wall cavity after sheathing removal Observations Wood strapping was nonexistent on the projecting wing wall. The building paper, sheathing and wood studs are severely affected by moisture and rot. Comments The overall investigation tends to indicate that this situation is localized in this specific area. The lack of drainage, venting, combined with snow build up in winter, are factors that can likely lead to such deterioration of the wall assembly. The positive element here is that all other openings revealed sound sheathing. 5

9 Ste-anne-des-pays-bas Church 2.3 Investigation on North façade (above side entrance) One opening was conducted above the north side entrance as shown in figure 13 below. Figure 13 Opening above north side entrance Figure 14 Boards in contact with roof shingles Figure 15 Absence of appropriate flashing detail Observations The wood siding is in contact with the roof shingles and is affected by moisture and rot. The sloped strapping does not promote water evacuation from behind the siding. The strapping and boards are affected by moisture and rot. Comments The absence of an adequate flashing detail and proper set back from the siding material in relationship with the roof shingles create opportunity for water to seep into the boards thus creating deterioration (rot). 6

10 Ste-anne-des-pays-bas Church 2.4 Investigation on North façade (right hand side) Two openings were conducted on the right hand side of the North façade as shown on figure 16. Figure 16 Openings on the North Façade (right hand side) Figure 17 Edge of upper board unsealed Figure 18 flashing does not appear continuous Observations The cut edge of the upper board is unfinished (no touch up paint), allowing moisture penetration. Board overlap is weak. There is a gap at the siding and fascia board and it appears that driving rain can get behind the roof flashing and the wall siding. There appears to be no continuity between the fascia and wall to ensure water tightness. Comments Above observations are self-explanatory. 7

11 Ste-anne-des-pays-bas Church 2.5 Investigation on South façade (left hand side) Three openings were conducted on the right hand side of the North façade. Figure 19 below shows the left and center openings. Figure 20 shows the right hand opening on the wall in question. Figure 19 General view showing 2 of 3 openings on this wall Figure 20 No flashing detail Figure 21 Siding in contact with roof shingles Observations The wood siding is in contact with the roof shingles. The sloped strapping does not promote water evacuation from behind the siding. The strapping and boards are affected by moisture and rot. Comments The absence of an adequate flashing detail and proper set back from the siding material in relationship with the roof shingles create opportunity for water seeping into the boards thus creating deterioration (rot). 8

12 Ste-anne-des-pays-bas Church 2.6 Investigation on South façade (above side entrance) Similarly to the north side lateral entrance, we have conducted an opening in the wall above the south side lateral entrance as shown on figure 22. Figure 22 Repairs made by Church volunteers to address rotting boards Observations The wood siding is in contact with the roof shingles and is affected by moisture and rot. The sloped strapping does not promote water evacuation from behind the siding. The strapping and boards are affected by moisture and rot. Comments The absence of an adequate flashing detail and proper set back from the siding material in relationship with the roof shingles create opportunity for water seeping into the boards thus creating deterioration (rot). 2.7 Investigation on South façade (above foundation wall) Similarly to the north side (lower left hand portion), we have conducted an opening as in figure 23. Figure 23 9

13 Ste-anne-des-pays-bas Church Observation In this case, strapping was present behind siding. Vertical corner trims are deteriorated. Building paper and vertical strapping appear dry. Comments: The severe deterioration described in point was not repeated here. The deterioration of the trims may indicate lack of preventative maintenance. 2.8 Investigation on East façade (left hand side) The last two openings were made in locations shown in figures 25 and 26. Figures 25 & 26 East façade showing two openings in the diagonal siding Figure 27 Close up on lower opening 10 Figure 28 Cracked siding

14 Ste-anne-des-pays-bas Church Figure 27 Showing curled siding Figure 28 Top of siding is curled out beyond siding overlap Figure 29 Curled siding Observations The nailing pattern is not consistent (16 20 o.c) and the siding is nailed on the bottom of the siding. The top of the siding is curling out and the water can get behind the siding. Cracking of the siding is also occurring. Comments The lack of support of the siding by variation in nailing/ strapping / overlapping patterns allows greater chance for curling and warping therefore creating greater opportunity for water penetration. 11

15 Ste-anne-des-pays-bas Church 3 Findings The findings indicate that the building paper and sheathing (OSB) beyond the siding and its strapping are sound. The only case of sheathing being severely deteriorated is at the top of foundation wall on the north side (figures 11 & 12). Based on the above findings, the following general concerns were noted and are considered problematic: There is insufficient nailing of the siding and inconsistent nailing pattern to the strapping. The strapping pattern is inconsistent. Overlapping of the siding is generally inadequate and in some cases nonexistent. Priming at the edges of the board is inconsistent. Boards are in direct contact with roofing materials and masonry. Metal flashing details between siding and roofing material are missing. Wall cavity drainage is obstructed by strapping in many cases. For the specific north wall at top of foundation wall level: The absence of strapping created a non-ventilated and non-draining condition causing the rotting of the assembly. For the leak reported above the north lateral entrance: The lack of a proper flashing detail is likely the cause of water penetration though the roof. In summary, the findings reveal two key aspects causing, in our opinion, the deterioration for the siding: Poor execution of the work in failing to apply normal installation principles for this type of siding application. The absence of adequate flashing details. Note: The fact that the siding is diagonally placed certainly affects how the water behaves on the surface and how it trickles down. The butt joints between the siding boards are more vulnerable to water damage than in a pure horizontal application. 12

16 Ste-anne-des-pays-bas Church 4 Recommendations and opinion of probable cost The recommended scope of repairs is the following: Remove existing siding, strapping and building paper. Verify that the existing sheathing is sound and dry (which should be the case based on the above findings) and make repairs where required. Install a new continuous air barrier and ensure adequate flashings connections with adjacent roof surfaces. Install new strapping with adequate spacing and ensure adequate drainage details following proper rain screen principles approach. Install new light weight cladding system. We recommend that the Church hire an architect to provide material selections, detailed design (tender drawings and specifications), and provide tender and construction administration services in order to protect the Church s interests and minimize risks. We understand that the Church may be considering vinyl siding as an option mainly for its low cost and low maintenance. This being said, we recommend that, in the next stage (detailed design) the Church evaluates an array of lightweight cladding options for the project and makes an informed decision based on cost, maintenance, performance, useful life etc. in order to select the most appropriate cladding for its specific building conditions. For instance, one item we would like to point out, among others, is that vinyl siding may not allow the type of flashing details (watertight wall and roof connections) that we feel the building requires and deserves. At this pre-design stage, we evaluate the cost magnitude of the above identified scope of repairs to be in the range of $235,000 to $300,000 depending on the new light weight cladding system selected. This monetary magnitude includes contractor s administration and profit and construction contingency (10%). This amount excludes taxes, professional fees for design and construction administration services. 13