Anybody involved in construction for any period of time at some level, whether designer, contractor, supplier or subcontractor, will have had to deal with a partly completed project. This project may have needed fixing or redoing. As you know, these contracts demand the difficult process of peeling back the layers and usually resetting a client´s expectations. Many who have experienced a redo situation are reluctant to attempt it again because of the time and effort involved. New issues that arise during the process make it impossible to cost a redo job until you get started, because that´s when you really see what issues have to be dealt with based on the previous contractor´s mistakes.
Vancouver Gas Fireplaces (VGF) was approached about a redo situation involving ten partially completed fully custom fireplaces at one residence. VGF´s first reaction was to offer advice from a distance and then run for cover! The contractor persisted however, and convinced VGF to work together to sort out the situation. His client was committed to solving the problems to achieve the original design intent and was willing to work with sections of the job at a time to allow for reasonable costing projections. He was also willing to pay fully for our time and effort to assess the situation. Under these circumstances, we found it hard to say no.
The main design intent was to create over-sized unconventional fireplaces in varying configurations with various soapstone and steel finishes. The burners themselves were for the most part scheduled to be sand pan style burners with logs on them. In some cases, the burners were to be built into plinths of raised soapstone inside the fireplace enclosures, while others were to be set flush with the floor. One of the burners was simply to be a linear line of flame placed into a specialized steel enclosure, which was a continuation of an exterior wall. The main issues that remained unsolved were the stack temperatures, which were deemed to be unsafe as were potentially the fireboxes. To add to this, the units were not burning cleanly.
After studying the plans and pictures provided (the project was in another province), VGF worked out some potential courses of action, solutions, and a rough budget. The contractor then came to our office to review VGF´s plans. At that time, we showed him both the test pictures and our examples of custom fireplaces under construction that presented the solutions we were proposing. We then traveled to the project site, studied each fireplace, and took pictures. Later, we also met with the affected sub trades, who would be installing and implementing the fireplaces, to discuss VGF´s plans and solutions.
VGF determined the following causes to the problems with the existing installations: We felt the burners were over-fired for the effect that they were trying to create. Although in theory there was adequate fresh air supplied to the fireplaces, there was no provision in the existing burner set-ups to allow for the distribution of the air up and through the combustion process. With the burners being over-fired, too much of the air was being used in primary combustion, not leaving enough dilution air to aid in cooling and venting. The fireplaces were for the most part built as hybrid fireplaces; steel stud cement board and heat barrier material with non-combustible material for interior finishes. In theory, this construction set-up could work, but the combination of over-fired burners and in some cases the integrity of the construction layers gave cause for concern.
Our solution was to approach the fireplaces as complete new zero clearance sealed fabrications, removing all the existing work back to the framing. In this way, we could control the fireplace environment, size the burners, and build in allowances for the proper circulation of the make up air. VGF took the step to ensure there would be adequate safety and drafting by changing the venting specs from a B vent to an insulated A vent. This venting change would increase the natural drafting potential of the fireplaces with the vastly superior heat retention qualities of A vent. As well, VGF set up a pre-purge cycle with a vent top draft inducer to ensure a pull-through for the fresh air make-up prior to initiating the combustion.
Past experience with setting up sand pan burners has taught us how to maximize the flame pattern and have a clean burn with the minimum amount of gas. Burner optimization mainly depends on the placement of the burners in the sand pans, the depth of the sand, and the placement of the logs. For the one linear burner, we used a set-up designed for previous projects that provided a controlled even clean burn.
Once we set up the procedures for all the fireplaces, the biggest issue involved how to incorporate the finishes into the zero clearance style of fabrication so that they did not look like zero clearance metal fabrications. The primary finish was 2 1/4” thick beautiful gray-blue soapstone. To achieve the desired affect, the designers were required to work from the inside out in three dimensions. For some conditions, this process was complicated by fireplaces that had partial glass return sidewalls.
In the end, VGF fully appreciated the opportunity to get involved in this do over. Our success was made possible by the persistence of the contractor to get things done right and the commitment of the client to achieving the desired end product.
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