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Conformance to

 

CSA 0122-06,

CAN/CSA 086-09 

CSA 0112.9-10

CSA 0112.10-08

CSA 0141-05 (R2009)

CSA 0177-06 (2015)

CHBDC   go to    www.bridgedecks.ca

 

Preparing for 

ANSI PR 320-2015 

WOOD MEETS CODE
Advanced technology and modern building codes are expanding the opportunities for wood in construction.
WOOD COSTS LESS

Wood products offer advantages in terms of material, construction and environmental costs.

WOOD IS RENEWABLE

Wood is a renewable and responsible choice that helps reduce our environmental footprint.

What is Prefabrication? ...offsite construction of

  • panelized solutions....( open frame or closed framing with additional elements)

 

  • building components precut or machined .....(such as Cross Laminated Timber, Glulam, Mass Timber, Heavy Timber, Dowel Laminated Timber,etc)

 

  • volumetric components likely three dimensional modules shipped from factory to site for integration  

 

Objective

Create better performing buildings that meet stringent code requirements as consumers are demanding high quality structures, delivered quickly and at a reasonable price.

Homebuilders may spend the majority of their time waiting, whether for trades, weather, deliveries or other delays.

 

What are the advantages to the prefabrication process?

Material and Cost Savings

  • Human error is reduced
  • Reduced waste and disposal costs
  • Savings due to volume purchasing
  • Material is optimized using computer software
  • Jobsite labour is dramatically reduced
  • Less building materials available for theft

Higher Quality Standards

  • Factory controlled conditions result in panels that are accurate and better fitting on-site
  • Reduced warping, shrinkage and floor squeaks due to quicker close in
  • Our Panelized process uses premium grade lumber and materials
  • Panels are built by experienced workers using the latest computer software resulting in a consistent and uniform product

Reduced Construction Time

  • More reliable completion and move in date
  • Construction loan and interest charges are reduced due to a quicker completion time
  • Delays due to material shortages and labour scheduling are reduced
  • Construction becomes more feasible year round

 In a plant, skilled labour can work on construction in shifts, rather than the typical single shift of skilled labour on site.

The advantages in terms of quality are compelling for factory-constructed panelized buildings which are not necessarily cheaper than conventional on-site wood constructions, but the advantages can be measured in controlled manner.

Additionally, Guardians factory’s high construction volumes allow them to demand premium-quality materials from suppliers.

Materials are sorted before they enter the manufacturing process and any defects are rejected, including badly warped or knotted studs. This is in stark contrast to the “no picking, no sorting” notices typically seen at lumberyards. Guardian has finger jointing equipment to remove defects and produced value added products.

The environmentally controlled factory environment allows for wood to be properly handled, stored  not subject to the elements as they would be on a construction site, where materials are often unprotected from rain or subjected to freezing. 

The assembly process itself is also highly controlled and incorporates testing. For instance, floors are constructed with 4’ x 12’ x 7/8” OSB and assembled with high-quality low-VOC elastomeric glue. Machine-controlled nailing ensures that the specified nails and spacing are used, and each nail is precisely centered in its joist or stud. Samples are tested after 24 hours, seven days and 30 days, ensuring a solid, no-squeak floor. Since the glue can cure in a controlled environment free of water penetration, the panels are unlikely to develop “freeze crack” once the heat is turned on in a building, and there is no need for surface sanding to correct edge expansion of the OSB. The floor panels are all designed to the highest building code standards for deflection, allowing porcelain tiles to be installed on any OSB floor surface without concern that the grout will crack. 

Factory-built wall panels, for their part, are also higher-quality products. Machines that control the spacing and depth of nailing make a noticeable difference in shear-wall construction–averting on-site arguments with builders due to common mistakes that affect shear-wall performance, such as over-nailing.

Two pre-drilled holes in each stud allow electrical wiring to be quickly installed.

Finally, wall panels are equipped with a high-quality air barrier that will experience no wind loads greater than the wind from delivery trucks travelling at posted speed limits. In the final building, further air leakage is reduced due to the precision fit of the panels. 

For both wall and floor panels, efficiencies in terms of material and time are notable. Wood LVL, PSL, LSL and I-joists are all delivered to the factory within 1/16” of specified length. Other materials are cut in a planned way to minimize waste. For clients seeking extra LEED points, wood can be specified from certified forests. 

Factory construction ensures safer and more efficient labour conditions.

In Part 9 of the National Building Code, where, regardless of professional engineering or architectural credentials, all are permitted to construct simple buildings less that 600 square metres in floor area and three storeys in height. The tacit prerequisite for the use of the rafter tables referenced in National Building Code Article 9.23.4.2 is a firm grasp of the imperial framer’s square.

Today, the articles of Part 9 referring to timber structural design are becoming quickly obsolete with declines in common skill, changes in timber technology, improved timber products, consumer demand for much larger homes (and spans that exceed the building code design tables), and the requirement by many building departments for stamped engineering drawings regardless of building size. 

Panelization with its sophisticated construction and longer spans makes timber construction securely a family member in Part 4 of the National Building Code, taking its place alongside steel and concrete in terms of use and spans.

Changing building codes are encouraging timber construction up to six storeys.

 Working in concert with an enlightened developer, the architects are employing panelized timber to construct a series of four-storey mid-rise residential buildings. Similar to modern European designs, HOT takes shape as a simple block with added modules. The long deck spans available with panelized construction allow for open plans and deep light penetration into the residential units. The use of renewable wood construction accrues measurable environmental benefits. 

Moreover, by building in wood, significant cost savings are achieved relative to a comparable concrete construction. In 2010, Grant Roughley of RHC Design Build assessed cost savings when constructing two buildings of identical size and occupancy, one with a steel structure and the second with wood construction. Grant concluded that the cost difference was 16.3% lower on the overall project budget for the wood-framed system.

Timber construction has evolved radically from the time when entire buildings were crafted on site. Over the past decades, individual building components have come to be assembled in factories and only installed on site. We are not far from a moment when, as Kent Larson of MIT’s Open Source Building Alliance puts it, “building homes on site makes as much sense as building a car in your driveway.” As its efficiencies and advantages emerge, it is clear that we are preparing for an era where panelization will take command. CA