City of Peterborough

Transcription

1 City of Peterborough Building Division Deck Guide Residential Information Guides This information is intended to only be used as a guide that outlines the minimum requirements for constructing decks and platforms, as well as what is required in order to make a complete application for a Building Permit. If you have any questions, feel free to contact the Building Division! May 2015 Questions? Phone: (705) x 1892 Web: 1 P a g e

2 General Requirements The following guide is provided to assist in clarifying the most critical health and safety requirements that will apply to an open, uncovered wood deck, for a residential building containing one or two dwelling units built to the standards of the Ontario Building Code, Part 9. For other projects, consult the Ontario Building Code for specific requirements. How to use this guide: This guide is intended to outline the minimum requirements for construction that are specified in the Ontario Building Code. The information contained in this guide will cover all the major Building Code Sections as they relate to residential deck construction. This guide is provided for informational purposes only. It is the responsibility of the owner, applicant, designer and contractor to review the Ontario Building Code to ensure that all construction meets or exceeds the current requirements. Any deck that will support a hot tub is required to be designed by a Professional Engineer. Best Practice When you see this, it indicates a best practice tip. While not required by the Building Code, a best practice is a recommendation based upon standard construction techniques and experience, and often gives the best results. 2 P a g e

3 Frequently Asked Questions Q: When do I require a Building Permit for my deck? A: A Building Permit is required for any construction on your deck project unless the deck area is less than 10m² (108ft²) and not adjacent to any other structure. Keep in mind that a deck/platform that does not require a Building Permit must still comply with the Zoning By-law with regard to location and heights. Q: How do I get a Building Permit for my deck? A: A Building Permit is obtained from the Building Division at City Hall by submitting a complete Building Permit application (see last question). A Building Permit will be issued within 10 business days if the drawings comply with the Ontario Building Code, are sufficiently detailed, and the application is complete. Q: Is it okay to start framing or digging foundations while you review my plans? A: No. Construction cannot start until a Building Permit has been issued. Q: How can I check to see if my contractor is licensed? A: At this time neither the province nor the City of Peterborough require licensing for most of the construction trades (except plumbers, electricians and sheet metal workers). Q: How much does the Building Permit cost? A: Building permit fees are determined by City Council each year. For 2016, a Building Permit costs $19.96 for every $1000 of estimated construction value, with a minimum charge of $ P a g e

4 Q: How long does it take to get a Building Permit? A: Provided that the Building Permit application is complete (see last question), the application will be reviewed and a permit issued within 10 business days, however, applications with the proper information are normally processed much faster. Q: Why do I have to go through all this, it s just a deck right? A: A deck is a structural floor system, similar to the flooring system in your house. However, a deck is also directly subjected to wind, snow and rain loads, as well as being fully exposed to the elements. Often decks will fail slowly over time resulting in damage to not only the deck, but often the house. Occasionally decks can have catastrophic failures as seen in the picture below, which could not only result in loss of life or injury, but also in liability if the deck was constructed improperly or without a Building Permit. Don t let this happen to you! 4 P a g e

5 Q: Can you recommend the name of a contractor to help me build my deck? A: Unfortunately we are unable to recommend anyone specific to you; however, we suggest that you take time to fully research the contractor you intend on using. Ask for written quotes from contractors before starting and check their references. Ensure that the contractor carries valid insurance and is knowledgeable in the process of obtaining a Building Permit. Remember that the Building Code sets out the minimum standards of construction, so exercise care in your choice of contractor. As the property owner, you are ultimately responsible to ensure that a Building Permit has been granted before starting construction. Q: What is required for a complete Building Permit application? A: A complete permit application requires the Building Permit application to be filled out, including Schedule 1. Payment is also required along with two sets of construction drawings (either hand drawn or computer drawn) drawn to scale and dimensioned. A set of required construction drawings consists of a site plan, foundation plan, floor plan, and cross section drawing. All plans must be drawn to scale and fully dimensioned. The site plan must have at least the following information to be accepted: - Lot size and the dimensions of the property and location/dimensions of all existing buildings. - Location/dimensions of the proposed deck, including setbacks from the property lines. - Site Plans must have metric measurements. The foundation plan must have at least the following information to be accepted: - Foundation type and sizes. Also include footing sizes as required. - If pier style foundations are used, indicate spacing between piers. - Structural framing layout: 5 P a g e

6 - Joist sizes, spans and spacing. - Beam sizes, spans and spacing. - Stair foundation and landing details. - Detail of connection to house. - Plans will be accepted in either metric or imperial measurements. The floor plan must have at least the following information to be accepted: - Decking material. - Guard style (if installed). - Stair sizing: - Tread depth and riser height. - Stair width. - Handrail construction detail. - Include any other built-in features such as benches or outdoor kitchens. - Plans will be accepted in either metric or imperial measurements. The cross section detail drawing must have at least the following information to be accepted: - Height of deck clearly shown. - Foundation type and sizes. Also include footing sizes as required. - If pier style foundations are used, indicate spacing between piers. - Show foundation depth. - Show existing foundation of house. - Structural framing: - Joist sizes and beam to joist connection details. - Beam sizes and post connection details. - Guard style (if installed). - Detail of connection to house. - Plans will be accepted in either metric or imperial measurements. 6 P a g e

7 Construction details These pages will outline the Building Code requirements and construction details that should be utilized for the design and construction of a residential deck serving not more two dwelling units. FOUNDATION SYSTEMS: Foundations for decks must comply with Footings and Foundations of the OBC. The depth of excavation must meet Excavation requirements. Undisturbed Soil: Regardless of the foundation style, the footing of the foundation must always bear on undisturbed soil. If the footing is to be located within 1.5m (5 ) of an existing building, then the footing for the deck must extend to the depth of the footing for the building it is adjacent to. Footings must always bear on undisturbed soil, as disturbed soil will compact after construction, causing the structure to list or tilt. Disturbed soil is any soil that has, at any time, been backfilled. Depth: Footing depth is determined based on geographical area. For the City of Peterborough, minimum footing depth is 1.2m (4 ). The reason that the footing depth is required is to prevent frost heave. During the winter, moisture in the ground will freeze and expand, causing heave. This is a phenomenon known as Ice Lensing. If the footing has not been placed deep enough, the heave will cause the deck footing to fail by pushing it up during the winter and allowing it to settle during the spring. 7 P a g e

8 Frost protection for footings is not required if the deck meets all of the following four conditions: 1) The deck is under 600mm (23-5/8 ) in height (see diagram, next page) 2) The deck is not attached to any structure 3) The deck is not supporting a roof (which includes a pergola/trellis) 4) The area of the deck is not more than 55m² (592 ft²) A deck that meets all of the above conditions is permitted to be constructed with a surface foundation system. In order to construct a deck foundation like this, the surface must still be prepared by removing all the topsoil and organic matter, but there is no requirement for the minimum footing depth. The footing must rest on undisturbed soil. Soil is only considered to be undisturbed if it is native soil and not backfill If you intend to build a deck with a full depth foundation system, you are permitted to attach the deck to the structure of your house. This will eliminate the need for an additional row of supports near the building. The footings must extend to a minimum of 1.2m (4 ) below the surface. Backfill: After a foundation system has been installed, it should be backfilled in such a way that will prevent damaging the foundation. The fill should be free of organic matter, pyritic material (rock containing iron) or any objects larger than 250mm (10 ). Best Practice Ideally the fill should be comprised of gravel, which is a mix of 1 stone and small aggregates. Foundation Types: There are multiple types of foundations that are acceptable for supporting a deck. The most common is a pier type foundation. 8 P a g e

9 Beam Length Footing Sizes: Footings are sized based on the load that will be imposed upon them. This is determined based on the area of the structure overtop of the support, also known as the Tributary Area. The Tributary Area is calculated as the area halfway between adjacent supports. If the members are cantilevered beyond the supports, the area of the cantilever is also included, as this is bearing directly on those supports. The size of a footing (also known as the footing area) is calculated based on the following formula: For convenience, the following two charts can be used to help you calculate the minimum footing area depending on the beam length and supported joist length. The chart below is a simplified chart, while the chart on the next page offers a more detailed breakdown of sizes. Minimum Required Footing Area - Simplified Supported Joist Length dia. 12 dia. 13 dia. 15 dia. 16 dia. 16 dia. 17 dia dia. 13 dia. 15 dia. 16 dia. 17 dia. 18 dia. 19 dia dia. 14 dia. 16 dia. 17 dia. 18 dia. 19 dia. 20 dia dia. 15 dia. 16 dia. 18 dia. 19 dia. 20 dia. 21 dia dia. 16 dia. 17 dia. 19 dia. 20 dia. 21 dia. 22 dia. 9 P a g e

10 Beam Length Minimum Required Footing Area - Detailed Supported Joist Length x 7 8 x 8 8 x 8 9 x 9 10 x x x 11 8 dia. 9 dia. 9 dia. 10 dia. 11 dia. 12 dia. 12 dia. 7 x 7 8 x 8 9 x 9 10 x x x x 12 8 dia. 9 dia. 10 dia. 11 dia. 12 dia. 13 dia. 13 dia. 8 x 8 9 x 9 10 x x x x x 13 9 dia. 10 dia. 11 dia. 12 dia. 13 dia. 13 dia. 14 dia. 8 x 8 9 x 9 10 x x x x x 13 9 dia. 11 dia. 12 dia. 13 dia. 13 dia. 14 dia. 15 dia. 9 x 9 10 x x x x x x dia. 11 dia. 12 dia. 13 dia. 14 dia. 15 dia. 16 dia. 9 x 9 10 x x x x x x dia. 12 dia. 13 dia. 14 dia. 15 dia. 16 dia. 17 dia. 10 x x x x x x x dia. 12 dia. 13 dia. 15 dia. 16 dia. 16 dia. 17 dia. 10 x x x x x x x dia. 13 dia. 14 dia. 15 dia. 16 dia. 17 dia. 18 dia. 10 x x x x x x x dia. 13 dia. 15 dia. 16 dia. 17 dia. 18 dia. 19 dia. 11 x x x x x x x dia. 14 dia. 15 dia. 16 dia. 17 dia. 18 dia. 19 dia. 11 x x x x x16 17 x x dia. 14 dia. 16 dia. 17 dia. 18 dia. 19 dia. 20 dia. 12 x x x x x x x dia. 15 dia. 16 dia. 17 dia. 18 dia. 20 dia. 21 dia. 12 x x x x x x x dia. 15 dia. 16 dia. 18 dia. 19 dia. 20 dia. 21 dia. 13 x x x x x x x dia. 15 dia. 17 dia. 18 dia. 20 dia. 21 dia. 22 dia. 13 x x x x x x x dia. 16 dia. 17 dia. 19 dia. 20 dia. 21 dia. 22 dia. 13 x x x x x x x dia. 16 dia. 18 dia. 19 dia. 21 dia. 22 dia. 23 dia. 13 x x x x x x x dia. 17 dia. 18 dia. 20 dia. 21 dia. 22 dia. 23 dia. 13 x x x x x x x dia. 17 dia. 19 dia. 20 dia. 21 dia. 23 dia. 24 dia. 14 x x x x x x x dia. 17 dia. 19 dia. 21 dia. 22 dia. 23 dia. 25 dia. 14 x x x x x x x dia. 18 dia. 19 dia. 21 dia. 22 dia. 24 dia. 25 dia. 14 x x x x x x x dia. 18 dia. 20 dia. 21 dia. 23 dia. 24 dia. 26 dia. 15 x x x x x x x dia. 18 dia. 20 dia. 22 dia. 23 dia. 25 dia. 26 dia. 15 x x x x x x x dia. 19 dia. 21 dia. 22 dia. 24 dia. 25 dia. 26 dia. 15 x x x x x x x dia. 19 dia. 21 dia. 23 dia. 24 dia. 26 dia. 27 dia. 15 x x x x x x x dia. 19 dia. 21 dia. 23 dia. 25 dia. 26 dia. 27 dia. 10 P a g e

11 Best Practice Oversize the footings by 25%. This will help to accommodate any changes/error to the framing and provide a sturdier structure. Alternative Foundation Systems: Pre-engineered foundations systems are becoming increasingly popular for a variety of reasons. Some products utilize a preformed plastic base to assist with forming concrete. Other products, such as helical steel piles, eliminate the need for concrete all together. When using a Pre-engineered foundation system, it is important to follow the manufacturer s specifications for determining allowable loads and/or spacing requirements. FRAMING: Framing for decks must comply with Wood-Frame Construction of the OBC. The Columns must meet Columns requirements. Columns: Columns are the vertical members that transfer and carry the load of the deck from the beam system to the foundation system. Columns can be constructed of steel, solid concrete, concrete masonry units, or wood. Concrete Columns: A concrete column can be either solid concrete, or concrete masonry units (CMUs). If it is solid concrete, it must be at least 230mm (9 ) in diameter or 200mm x 200mm (8 x 8 ). Unit masonry columns must be at least 290mm x 290mm (12 x 12 ) or 240mm x 380mm (10 x 16 ) Wood Columns: A wood column must be the greater of: i) 140mm (5.5 ) x 140mm (5.5 ), aka 6 x6 nominal or ii) the width of the supported member (beam). 11 P a g e

12 A wood column can either be a solid member or built-up. If it is built-up, it must consist of members that are at least 38mm (1.5 ) thick, nailed together with no less than 76mm (3 ) nails at 300mm (12 ) on centre. Beams: Beams are the horizontal structural members that transfer the load from the floor system to the columns. Beams can be constructed of either wood or steel. Wood beams must be of a built-up style as shown below. The use of Solid Sawn timbers must be supported by calculations, which would involve retaining the services of a Professional Engineer. Beams are sized based on the amount of load transferred onto them. This involves knowing how long the floor joists are that will bear weight on them. The supported length is measured as half the sum of the joist spans on both sides of the beam. If the joists are cantilevered beyond the beam, you would also include the length of the cantilever. See the chart below to determine the beam size: Maximum Beam Span, m (ft) SPF No. 2 Lumber Supported 3-38x184 (2 x8 ) 3-38x235 (2 x10 ) 3-38x286 (2 x12 ) Length of Joists 2.4 (7-10 ) 3.07 (10-0 ) 3.92 (12-10 ) 4.57 (15-0 ) 3.0 (9-10 ) 2.85 (9-4 ) 3.52 (11-6 ) 4.09 (13-5 ) 3.6 (11-9 ) 2.63 (8-7 ) 3.22 (10-6 ) 3.73 (12-3 ) 4.2 (13-9 ) 2.44 (8-0 ) 2.98 (9-9 ) 3.46 (11-4 ) 4.8 (15-9 ) 2.28 (7-6 ) 2.79 (9-2 ) 3.23 (10-7 ) Beam Splicing: It is recommended that beams be installed so that they are comprised of full length plies. Lumber up to 16 lengths are commonly available at most yards, and some yards are able to order lengths up to 24. When it is not feasible to use a full length, it is permissible to splice a beam to increase the length; however, this must be done carefully to ensure the construction will comply with the prescriptive requirements of the code. A beam can only be spliced in one of two locations. Ideally it would be 12 P a g e

13 spliced directly over a mid-support (eg. centre column in a deck with 3 or more supports). A single individual ply of a beam can also be spliced within 150mm (6 ) of the ¼ point of a span adjacent to a mid-support. See the image to help visualize this. Acceptable Locations for a beam splice Unacceptable Locations 13 P a g e

14 Joists: Joists are the part of the flooring system that transfers the load of the decking to the beams. The spacing of the joists will often be determined based on the choice of decking and installation. Composite decking, or decking installed at a 45 degree angle can require closer spacing. The spacing of the joists also has an effect on the span of the joists. If the joists are closer, then the joists can span further. The following chart may be used to determine the size of joists you will require: Maximum Joist Span, m (ft) SPF No. 2 Lumber Joist Size & Spacing Maximum Span 38x184 (2 x8 ) at 305mm (12 ) o.c (12-2 ) 38x184 (2 x8 ) at 406mm (16 ) o.c (11-7 ) 38x184 (2 x8 ) at 610mm (24 ) o.c (11-0 ) 38x235 (2 x10 ) at 305mm (12 ) o.c (14-4 ) 38x235 (2 x10 ) at 406mm (16 ) o.c (13-7 ) 38x235 (2 x10 ) at 610mm (24 ) o.c (13-0 ) 38x286 (2 x12 ) at 305mm (12 ) o.c (16-4 ) 38x286 (2 x12 ) at 406mm (16 ) o.c (15-7 ) 38x286 (2 x12 ) at 610mm (24 ) o.c (14-10 ) Joists are permitted to cantilever beyond the beam provided that, for a 2 x8 the cantilever does not exceed 400mm (16 ), or for a 2 x10 or larger the cantilever does not exceed 600mm (24 ). Decking: SPF wood decking is required to be installed so that the maximum distance between supports is not more than 600mm (24 ), but in many instances joist spacing must be reduced. If the decking is installed at a 45 degree angle to the joists, the joists may have to be installed at 300mm (12 ) or 400mm (16 ) on centre, if a cantilever picket guard is installed, joists may have to be installed at 400mm (16 ) on centre, if a Northern Species of wood decking is used (such as cedar), supports must be not more than 400mm (16 ) on centre, and if composite decking is used, the manufacturer s specifications determine the support spacing, which in some cases may be 300mm (12 ) on centre. 14 P a g e

15 STAIRS, RAMPS, HANDRAILS & GUARDS: Stairs for decks must comply with to of the OBC. The construction of ramps must meet requirements. Landings are often mandatory at the top and bottom of stairs and ramps, and must be constructed to of the OBC. Handrails are often required on stairs and ramps and are required to be installed as per the requirements of Guards (aka Guardrails/Railings): A Guard is the component of a deck that is designed to prevent someone from falling off the walking surface. Guard is the proper term for this element, it should not be called a Railing, which is not a proper building term and does not distinguish it from a Handrail (which is design to assist a person when using a stair/ramp). Please see the separate handbook entitled, Guards for Residential Decks, or SB-7 of the Ontario Building Code for the requirements for installation. Handrails: It is recommended that a handrail be installed regardless of the number of risers, but it is not always required. A handrail is a required component when an exterior flight of stairs has more than 3 risers, or if a ramp rises more than 400mm (16 ). A handrail must be graspable and continuous along the entire length of the flight of stairs. Best Practice You should be able to wrap your entire hand around the handrail and it should be no larger than 2 wide. A piece of galvanized pipe, steel stock, or a wood 2 x2 can be used. A 2 x4 on edge is not a suitable handrail, since the average person cannot fully grasp it. The handrail must have a clearance of at least 50mm (2 ) between it and any surface behind it. The height of the handrail must be between 865mm (34 ) and 965mm (38 ), measured vertically at the nosing of the tread, or 15 P a g e

16 the surface of the ramp. A handrail on a landing is permitted to be between 865mm (34 ) and 1070mm (42 ), which allows for the proper transitioning of stairs between landings. Handrails are required to be supported at attachment points no farther than 1.2m (4 ) apart, with support required within 300mm (12 ) of each end of the handrail. Stairs: When stairs are constructed, it is very important that they are constructed safely to prevent injury/accident to people who use the deck. If the stairs serve part of a required building exit, provisions in addition to those below may also apply. For simplicity, this section only covers straight stairs. Curved stairs or straight runs with winders have additional requirements. Stair Width: Stairs are required to have a minimum width of 860mm (2-10 ), measured between the inner faces of the stringer or guard. A handrail can project into this required width up to a maximum of 100mm (4 ). Stair Risers: The riser of a stair is measured as the vertical nosing-to-nosing distance and must be between 125mm (4-7/8 ) and 200mm (7-7/8 ). The height of risers can not vary by more than 5mm (3/16 ) between adjacent risers. However, all risers in a flight of stairs can not vary by more than 10mm (3/8 ). For example, if the largest riser height in a flight was 7-1/4, then the shortest riser could not be less than 6-7/8. Stair Treads & Run: The tread depth of a stair is different than the run of a stair. The run is measured as the horizontal nosing-to-nosing distance, while the tread depth is the measurement of the entire horizontal surface where one can step. The run of a stair can be no less than 210mm (8-1/4 ), but no more than 355mm (14 ). The maximum variance of treads is the same as that 16 P a g e

17 for risers, which is a maximum tolerance of 5mm (3/16 ) between adjacent treads and no more than 10mm (3/8 ) between the deepest and shallowest treads in a flight. Stair Landings: A landing is required at the top and bottom of every flight of stairs, except when stairs have no more than 3 risers. The dimensions of the landing shall be no less than the full width of the stairs, and at least 900mm (3-0 ) deep. The landing is required to be a level area with a slope of no more than 1 in 50 (2%). If a landing is not required, and the bottom riser adjoins a finished sloping surface (such as a driveway), the riser height measured across the bottom riser is permitted to have a variation of no more than 1 in 12. Stair Foundations: The base of the stringer is required to be supported and secured to a foundation. Depending on the number of risers, the necessary foundation for the stairs will vary. All stairs that are constructed must be supported and secured at the top and bottom. The top support is most easily achieved by using a mechanical hanger that is designed to support stairs. The bottom support can be done by notching a 2 x4 into the bottom stringer that is anchored to a concrete pad, similar to the image below: 17 P a g e

18 Sample Plans Framing Plan 18 P a g e

19 Sample Plans Cross Section 19 P a g e

20 Notes 20 P a g e

21 Notes 21 P a g e

22 Notes 22 P a g e

23 Required Inspections Inspections: After your permit has been issued, you will be required to notify the Building Inspector at various stages that you are ready to have your deck inspected. As you construct the deck, you will be required to have the deck inspected multiple times. Excavation (aka pre-footing) - You must call for this inspection after you have dug out all of the holes for footings, but before you pour any concrete. - If you are using a preformed footing base, this should be backfilled as per the manufacturer s instructions. - The Building Inspector will be checking the depth of the hole, ensuring that it is free of water/leaves, and that the size and location match the approved drawings. Framing (platform) - Every element of the framing is required to be inspected. At this inspection, the Building Inspector will review the columns, beams and joists. They will review the connections and ensure that the proper fasteners and hardware have been used. Framing (Guards) - If guards are required, or if they are not required but have been installed, they will need to be inspected fully. All components of the guard system are inspected, including the posts, rails and balusters. They will review the connections and ensure that the proper fasteners and hardware have been used. Final - At the last inspection, the Building Inspector will review any remaining elements and verify that construction has been completed. The Inspector will review the final framing, including the stairs, handrails and decking. 23 P a g e

24 Checklist A Building Permit application filled out (including Schedule 1) Payment ready (Cash, cheque or Interac Debit) Two (2) complete sets of drawings including: Site plan Foundation plan Floor plan Cross section drawing Questions? Phone: (705) x 1892 Web: 24 P a g e