ARTICLE#001 WHAT IS PRE-FABRICATED COLD-FORMED STEEL (cfs)?
Pre-fabricated cold-formed steel (CFS) construction has been dominating the low to mid-rise residential construction market as of late. The reason is simple, it is one of the most efficient building systems available to the market. The system leans on its advantages of being flexible, economical, fast, and easy to construct allowing building owners, architects, and developers significant benefits when integrating pre-fabricated CFS systems into their projects.
1. CFS shop drawings are created from architectural, structural, mechanical, and electrical construction drawings, where dimensions, heights, elevations, rough opening sizes, and member sizes are taken into account. Upon completion, these drawings are submitted for approval to consultants and owners prior to fabrication for review. This allows time for revisions, coordination, and optimizations.
2. Upon receiving approved drawings, the manufacturer gets to work, manufacturing studs, tracks, and bridging. These components are then assembled into wall and floor panels, where the shop drawings are used as instructions for the construction of the panels. It is important that the manufacturer has ample lead time to fabricate, ideally, fabrication occurs while the foundation is being completed, therefore, for successful execution it is important that the owner and consultants are all on the same page in terms of timing, approvals, and execution.
3. When the foundation is complete and the site is ready the panels are shipped to site on 50' trailer beds, the panels are then installed as per installation drawings, where typically a 10,000 ft² floor plate (wall and floors installed) can be constructed within two-weeks.
The complete process is transparent and streamlined, there is no time wasted during the design, fabrication, or construction stages of the project. Most importantly, consultants and owners can make rapid changes due to the implementation of BIM technology.
Direct and In-Direct Savings
AREAS OF ADVANTAGE
1. There are direct cost savings when constructing low and mid-rise building structures as within this range is where the system is optimized. Usually, resulting in the lowest $/ft² for the structural system.
2. Private residences are subject to long-term savings as CFS materials have tremendous resilience to the environments and do not have wood-related issues such as termites, shrinkage, expansion, creeping, moisture, and splitting. There are rarely any fitting issues when it comes to CFS construction as the quality of construction is much greater.
3. There is tons of flexibility in construction as the floor system is interchangeable from open-web steel joist, hollow-core, composite metal deck, joists, rafter, solid concrete slab, and really any other system, allowing for optimization in floor and roof costs.
When comparing CFS to cast-in-place concrete, due to CFS high strength to lightweight ratio, less weight of CFS material is required to carry the same building loads.
For example, when comparing floor system weights:
300 mm deep concrete slab's self-weight is 7.06 kPa (720 kg/m²)
300 mm deep composite metal deck self-weight is 3.48 kPa (354 kg/m²)
That is a 202% (366 kg/m²) weight increase from concrete to CFS! This is significant as more weight results in larger supporting elements and foundation.
COST OF CONSTRUCTION
Overall, the benefits of cold-formed steel systems can lead to direct and indirect savings to the project.
Direct and Indirect Savings
Reduced load-bearing element sizes
Reduced foundation sizes
Reduced floor system costs
Reduced construction time-line
Reduces the overall labour cost on-site.
Reduces construction waste
Minimizes costly weather delays
Ensures greater quality control
Reduces the builder's risk
Significant increase in the speed of construction.
Additional cost savings can include:
Lower project financing costs
Reduced crane costs
Less scaffolding rental duration
Developer insurance savings
Reduced project management fees