Renovation & Design

Small deck presents big challenge

Elevated structure had to be built to withstand 'wobble test'

Marc LaBossiere / Winnipeg Free Press

This high-level, self-supported deck, built adjacent to an above-ground oval pool, features a staircase and railings that showcase esthetically pleasing angular aspects throughout.

Marc LaBossiere / Winnipeg Free Press

Before the top-decking was introduced, the stairs’ framework was custom-built on-site.

Marc LaBossiere / Winnipeg Free Press

There was limited space around the pool to build the deck, and the neighbour’s fence is close by.

In the spring of 2014, a client of mine, Lynn Williams, contacted me regarding the possibility of designing a small but strategic deck that would allow convenient access to an above-ground oval pool.

Given the limited space around the pool, and due to its proximity to the neighbour’s fence, the deck would have to be high and small — and quite the challenge.

With a pool depth of more than four feet, the top surface of the proposed deck, adjacent to the pool’s edge at one end, would be constructed to an elevation just slightly lower than the lip of the pool’s top cap. To achieve the firm foundation required for a self-supported deck, three-quarter down gravel was first spread along the ground at the base of the pool wall, covering the entire footprint of the intended deck. Once the gravel was packed, four-inch-high 12-by-12 deck pads were strategically placed within the deck’s footprint, upon which the deck’s six support posts would rest. Precise height measurements of each of the four-by-four posts would ensure that the deck’s top-tier joisting structure is level. The deck mimics the curve of the pool’s oval on that side, by introducing a 10-degree angle midway through the long of the deck. Angular contours at either end of the deck further complete the esthetic desired.

With the posts in place, the outer two-by-eight joists were carefully secured to each post using six-inch TimberLok lag bolts, following the 10-degree angle at the midway point. The cross joists were then secured at a perpendicular, on 16-inch centres. Once the main framing was completed, two-by-four boards were used to stabilize any apparent wobbles by fastening one end of a two-by-four to the outer base of the end posts and to the outer top of the midway posts, and then performing the reverse with one end of a two-by-four to the inner top of the end posts and to the inner base of the midway posts. This process made the structure very rigid and nearly eliminated unwanted movement of the structure.

Before the top-decking was introduced, the stairs’ framework was custom-built on-site. Four six-tread stringers were cut from two-by-12 boards, using a pattern for a 7¼-inch rise with a 9¼-inch run. For ease of top-decking installation, the stairs were immediately completed with two-by-10 stair tops, and two-by-eight fascia — having a staircase to access the top of the deck for the remainder of the build made things much more efficient. Traditional two-by-six boards for the top-decking were secured to the joists with three-inch deck screws. And to perpetuate the 10-degree angle midway through the deck, the top-decking follows this pattern via a series of miter joints, which again enhances the deck’s design. The boards next to the top edge of the pool were scribed the curvature of the oval, carefully cut using a jig saw.

For reasons of safety, 42-inch-high railings were required along the outer perimeter of the deck, any place the deck was not adjacent to the pool. Four-by-four railing posts were notched at each base and subsequently affixed to the two-by-eight joist structure using six-inch TimberLok lag bolts — the railings must be firm and rigid. Two posts were also secured to the base of the staircase, which allows for railings on either side of the stairs. Top and bottom two-by-fours were set horizontally between each of the posts, and two-by-two balusters were affixed vertically at four-inch intervals. To complete the railings, two-by-six caps were then fastened to the top edge of the railings. The final step was to then fasten the two-by-eight fascia at deck level, between every post. It became very apparent that the top-decking had also increased the rigidity of the entire self-supported structure during the "wobble test," which essentially consisted of grabbing hold of the railings and swaying back and forth in an attempt to instigate deck movement… a futile exercise. The deck was ready for use!

Although this project was likely the smallest deck I had ever undertaken, it may have also been the most challenging from a design perspective. Self-supported decks at high elevations are always complicated, in that eliminating the potential for unwanted movement requires additional framing support. The introduction of an angle midway through the entire structure that follows the oval of an above-ground pool greatly increased the complexity of the project. Although this deck is rather tiny, it revealed some huge obstacles. Thank goodness for the adage "great things often come in small packages." This deck project will always remain one of my favourites — a testament to achievement, despite adversity.


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