March 1, 2013
By Joel Seibert
The idea of backyard decks have shifted from an outdoor area with the capacity to hold a table and a couple of lawn chairs to an extension of the home.Decks have always been a common place to gather with friends and family to enjoy a sunny summer day, or a warm summer evening. In its purest form, a deck is a raised structure attached to, or near the exterior of, a structure that is unprotected and left exposed to the elements. In the last 10 years, with the eruption of the Internet, ‘how-to’ manuals, and the advent of do-it-yourself (D-I-Y) television channels/programs, decks have morphed from their traditional form into some of the most elaborately designed structures associated with home construction.
The idea of a deck has shifted from an outdoor area with the capacity to hold a table and a couple of lawn chairs to an extension of the home. New Age decks, now commonly referred to as ‘outdoor living spaces,’ often include, but are not limited to, outdoor kitchens, hot tubs, pergolas, wet bars, and pools. A deck is, by definition, an unroofed porch or platform. That said, the sky is the limit as to what these structures can include.
This article details the process involved in creating large-scale decks and outdoor living spaces—from the initial meeting with the client, through the design/planning stage, to permitting, and construction.
During the initial meeting, visit the client’s site and survey the area where the deck is to be constructed, and record any measurements required for the design/planning stage. For the most part, a square foot measurement of the area the deck will encompass and a drawing with measurements detailing how the deck will attach to the house will suffice. However, for design and permitting purposes, a copy of the Real Property Report (RPR) should be obtained from the client.
Once the area has been determined, assess the client’s needs, wants, intentions, and budget for the deck as this information will prove useful in designing a custom outdoor living space specific to their needs.
When planning and designing the deck, the information collected during the initial meeting is compiled into a visual representation of the finished project. During this phase, deck design tools should be used to aid in the development process. These programs enable the entire project to be laid out, including all construction stages—from pilings to decking materials. Custom railing options can also be generated using these programs to create a full, visual replica of the project. Further, these programs are designed to extrapolate the substructure plans, making it easy to submit drawings to the building permit department for approval.
While planning, drawings, and decking components should be completed to scale, an overhead view works well during the planning and design stage. By starting with a scale bird’s-eye view deck drawing, features and/or accessories such as pergolas, hot tubs, outdoor kitchens, etc., can be measured accurately to best determine their location in the general scheme of the deck. If the deck is being built around large features such as a pool, spa, or garden, start the design with the placement of the feature and design the project outwards from its footprint.
At this stage it is also important to take into consideration the weight of any accessories being added to the deck. When possible, features such as pergolas and arbors that have posts incorporated in their construction, the posts should run through the deck frame to pilings in the ground (under the deck). This is beneficial for a number of reasons:
When additional pilings are added they must be documented on the construction plan. Pilings should be at least 1.2 m (4 ft) deep and 254 mm (10 in.) wide. This puts the base of the pilings below the frost layer and minimizes the chance of frost heaving, which can compromise the substructure’s structural integrity. Where heavy structures are installed and posts are unable to run through the deck, additional pilings, beams, and joisting should be added to the substructure.
Once the surface layout is complete, a structural cross-section drawing is required. These drawings are required at the permitting stage as they are far more detailed and encompass everything included in the substructure or frame. This drawing must include:
Beam and joist selection is based on the distance between points of contact. For example, the first point of contact (A) is considered to be where the joists are connected (via joist hangers) to the header board on the house, while the second point of contact (B) is where the joist intersects with the beam. The span, which is the distance between contact points A and B, determines joist sizing.
Joist sizing specifications can be found via the National Building Code of Canada (NBC) website (www.nationalcodes.nrc.gc.ca). Here, joist span charts will detail the proper joist size required, material, and number of plies suitable to span the desired distance.
It is important to determine the decking material that will be used on the surface early in the planning process. Many factors will play into the material selection, including amount of traffic, deck shape and location on the house, if it surrounds a pool or hot tub, client’s willingness to maintain the product, overall look the client is trying to achieve, colour preferences, budget, and the general desired use of the area. This list can be endless (see Figure 1).
Decking materials can be broken down into six major categories:
The material selected will play a role in how the deck is framed; framing plans will need to be detailed in the structural cross-section drawing.
The following plans are required by the City of Calgary at the application stage in order to issue a building permit for a wood deck. The permit application must be accompanied by:
For more details on the requirements for obtaining a building permit for deck construction, visit www.calgary.ca, or the website of the local municipality where the deck is being installed.
For those who are unfamiliar with building codes and regulations, applying for a permit is certainly one way to guarantee a successful project. Once the project’s drawings are submitted, they go to an inspector whose job it is to know the building codes. If the plan does not meet the code requirements, the application will be denied; however, suggestions will be made on the drawings in order to change them to meet code requirements when the plan is resubmitted for approval.
Once the plans have been approved, permits have been granted, and the client has signed off on the design, the project can commence. To avoid any surprises during inspection, and to maximize the potential for a successful project, remember this simple saying, ‘Plan the build, and build what is planned.’ Careful detail has gone into the planning process; therefore, it is important not to deviate.
With large projects it is always a good idea to start with a known point of elevation (this is a point that will not move throughout the duration of the project). This enables the different elevations in the project to be laid out accurately. Known points of elevation can be located anywhere on the property (e.g. a concrete drain swale in the corner of a backyard, or the edge of a swimming pool).
Start the project by measuring, re-measuring, digging, and setting the pilings. Prior to the concrete setting (but after it has been poured into the form), place the post saddles in the concrete. Next, fasten the header board (if one is required) to the structure where the deck will be attached. Once the header board is fastened securely (check local building codes for bolt specifications) the beam and post height can be determined.
Once the posts and beams are in place, hangers, joists, and torsional blocks can be installed. Prior to fastening the joists to the beam, make sure the sub-frame is square. On small decks, an easy way to do this is to place a sheet of plywood flat on the framed surface and line up the corner of the plywood with the corner of the deck. Then, adjust the frame so the edges of the plywood are flush with the outside joist and rim board.
On large decks, where there are multiple areas to be squared, divide up the areas and use the A² + B² = C² formula, then measure corner-to-corner to ensure the deck is square. When possible, do not fasten the joists to the beam until framing is complete, as this will make adjustments easy should anything need to be moved.
Once framing is complete and the joists are fastened to the beams, think about railing selection. If the railing requires the posts to be fastened to the frame (and not the surface of the deck), now is the time to lay it out. Once the railing has been measured and laid out, fasten the posts to the frame and block the posts accordingly. If the railing posts are surface mounted (to the top of the deck), laying out the railing and adding additional blocking for fastening the posts is still recommended.
When fastening the decking to the frame, be sure to use the recommended fastening system for the product being installed. This is pertinent for a couple of reasons:
Despite all the careful planning that goes into building a deck, there are bound to be hiccups throughout the build. By planning for some margin of error, the amount of time and effort spent solving these problems can be minimized. The most difficult errors to work with are those affected by permanent features, such as pilings. Making the pilings slightly bigger than required provides more surface area to land the support posts on. For example, if the plan calls for 203-mm (8-in.) pilings, increase the size to 254 mm (10 in.) or 305 mm (12 in.).
If the deck is to be surfaced with composite material, framing the deck on 305-mm (12-in.) pilings is suggested. Composite material absorbs heat; more so if a dark-colour composite is selected. By tightening up the joisting, it will minimize any bounce in the deck boards and create a stronger surface.
Finally, once the decking material has been installed, the final steps include an assessment by a building inspector, and finishing.
If the deck plans that were submitted with the building permit application were followed, the inspector will check for deficiencies and sign off on the completed project assuming there are no issues. After the inspection has been completed, paint and/or stain should be applied to treat the wood and protect it from the elements. There are many paint/stain options available. Take the time to find the product best suited to the client’s needs. In most cases, an oil-based stain product is recommended as these are typically a penetrant. This means the product soaks into the wood; therefore, not only protecting the outside of the wood, but also the inside. Keep in mind, when using a latex paint to treat the surface of the wood it seals out moisture; however, it also seals in moisture contained in the wood.
Editor’s note: The author is based in Calgary, Alta., and all codes and practices discussed within this article are either provincial or municipal guidelines. All contractors must comply with their own specific provincial and municipal building codes, which can be found on most city/town hall websites.
Joel Seibert, is the operations manager at Mountain View Building Materials in Calgary, Alta. They specialize in the design/build of decks, fences, and high-end residential exteriors. Seibert previously owned-and-operated a landscape construction and is the third generation of the family to enter the lumber industry. He can be reached via e-mail at firstname.lastname@example.org.
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