Which timber floor joist?
With a variety of timber joists on today's market, how can you be sure that you are choosing the system that is right for you? I'll first assume that you have already chosen timber joists over concrete or steel, possibly because you are aware that timber joists are more eco-friendly, less expensive, lighter weight and reduce cold bridging.
You now have the choice of timber open web systems such as ITW Industry's Alpine FloorTrus, metal open web systems such as Alpine SpaceJoist, trimmable open web systems such as Alpine TrimTrus, I-joists, or solid timber. In today's economic climate, cost is more an issue, but don't assume that the cheapest system will save you money in the long run!
Open web systems offer unique cost savings in joist installation time and wastage, followed by fast installation of services through the voids while reducing the potential for costly remedial works for incorrectly drilled or notched joists. Comparison studies on a like for like floor layout by ITW Industry has shown that open web joists over traditional solid timber joists will reduce number of joists, linear meterage of joists, load bearing walls & foundations, insulation and even the number of nails & screws. All these factors contribute to increase your bottom line.
So which open web joist system should you choose? Metal web joists are the lightest weight option while the timber web joists offer many more advantages, including ultimate design flexibility (any joist depth from 219 - 600mm and web configuration), exceptional acoustic and dynamic loading performance ("feels like a concrete floor") and robust in transport & site handling. Finally, trimmable open web systems are ideal when timescales are tight as they can be supplied as an off the shelf product.
