Summary
• easi-joist studs have been used in a large school dormitory project.
• Benefits include depth of wall and ease of service installation.
• Non-specialised merchants could form partnerships with timber engineering firms.

With the prominent expansion of I-joists into further areas of solid timber’s domain, it’s perhaps easy to overlook the role being played by metal web or “open web” joists. Like their I-joist counterparts, they are also looking to carve a slice of the systems market outside of floor installations.

Wolf Systems has its fingers in a vast array of sectors, from traditional roof truss technology, timber frame, floor and roof design and costing software, to the easi-joist metal web joist and prefabricated roof system smartroof.

One of its new development areas is using easi-joists, which feature TR26 top and bottom chords, as a wall system. The product is already used in applications ranging from floor cassettes to rafters for pitched roofs and joists for flat roofs.

Application of the new wall system, generally in closed panels, is still in its infancy, having been used for the past six months, but Wolf believes the market has potential. Already it has worked with SEED Homes Ltd in using easi-joist studs, including for a school dormitory project in Wales.

Timber frame interest

“It’s something that timber frame manufacturers have been talking to us about,” said Karl Foster, sales and marketing director for Wolf Systems. “The manufacturers have seen the opportunity in using the joists in walling applications. They see it as a product that differentiates themselves from other timber frame manufacturers.”

He said using easi-joists could create greater depth of walls than standard, commercially available solid timber, leading to lower U-values, while the lightweight nature of panels made for easier handling on site.

Other quoted benefits include greater dimensional stability than solid timber, greater airtightness and easier routing of cables and pipes.

Mr Foster said the system is really aimed at closed panel use in order to capitalise on the value-added advantages of incorporated insulation and ease of services installation. The 10-15% cost premium of metal web joists over I-joists also makes clear the product’s need to focus on the value-added market.

“At the moment it’s quite a niche market; it’s for timber frame manufacturers that are looking to supply into a part of their customer base such as self-builders or small developers.”

But Mr Foster has a view as to how the supply of such systems may develop beyond timber frame manufacturers. “Years ago we just had roof truss systems, now we see companies making trusses and also supplying engineered floor systems. If you look another 5-10 years in the future you would see these companies moving into wall systems.”

Need to diversify

With the advent of new products, such as roof panel systems, the roof truss market is decreasing so truss manufacturers need to diversify.

However, the only way non-specialised merchants can tap the market is by forming partnerships with timber engineering companies. Some Wolf timber engineering/timber frame customers, he said, have partnerships with larger merchant groups.

“In existing floor design you are engineering a component for that house. But if you are manufacturing and designing timber frame panels you are taking on the responsibility for the whole structure. That gives a level of complexity, so that is why timber frame manufacturers have been pushing it. It would be quite unusual to go to a builders merchant and buy a timber frame kit.

“There will always be a market for solid timber joists but it will decline as we focus on modern methods of construction,” said Mr Foster.

He said builders are increasingly looking beyond stick build and traditional timber frame and want a product that can easily and speedily meet the latest Building Regulations.

It will be interesting to see how wall systems develop, whether remaining a niche or breaking into the volume sector spurred by build speed and superior U-values.

Engineered timber floors

When it comes to the engineered timber floors, Mr Foster said I-joists still have the majority of the market and said some of the recent new entrants like Steico and Masonite Beams have made a real impact.

But he believes I-joists have now developed into a commodity product sold mostly on price, whereas metal web joists could provide more value through their ease of services installation, with the product gaining more ground year on year.