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The Global Insight

What are TJI joists made of

Author

Mia Horton

Updated on March 25, 2026

I-joists are comprised of top and bottom flanges, which resist bending, united with webs, which provide outstanding shear resistance. The flange material is typically laminated veneer lumber (LVL) or solid sawn lumber, and the web is made with plywood or OSB.

What material is used for joists?

Joists are either made of wood, engineered wood, or steel, each of which have unique characteristics. Typically, wood joists have the cross section of a plank with the longer faces positioned vertically.

What are floor joists made out of?

They are composed of a top and bottom flange (usually a 2×4) with a piece of plywood or OSB fixed perpendicular in between. The biggest benefit I-joists bring are the long span distances you can achieve.

What kind of wood is used for joists?

Wood Species The common types of wood used to make floor joists are redwood, hemlock, Douglas fir, and southern yellow pine.

What are TJI floor joists?

Trus Joist® TJI® joists are a key part of making a high-performance floor. TJI joists are lightweight and come in long lengths, which makes them faster and easier to install than traditional framing, and saves you both time and money. …

What is the main difference between plywood and LVL?

In general, LVL production is similar to that of structural plywood; however, the main difference between the two products is the grain orientation of each veneer.

What does TJI joist stand for?

TJI. Trus Joist I-Joist (engineered floor and roof joist; trademark of Trus Joist, a Weyerhaeuser Business)

How strong is an I joist?

Strength Characteristics of I-Joists Relative to Conventional Wood Framing. With respect to conventional framing (16 inches or 19.2 inches on center joist spacing), I-joists are 50 percent stiffer than solid sawn lumber.

How is engineered lumber made?

Engineered wood is a whole class of building products and materials. They’re made by binding pieces of real wood, scrap wood, shredded wood fibers and/or sawdust with adhesives to create products that look and act like wood but are designed to be stronger and more durable.

What grade of wood is used for floor joists?

There are 12 strength grades as set by the British Standard in the BS 5268, but the most commonly specified are C16 and C24. Both grades are used in structural applications and are suited to different loads. They can be used for rafters, floor joists, studwork for partition walls, formwork, shuttering etc…

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Can pine be used for floor joists?

Typically floors would be constructed from MGP10 H2 Pine or hardwood or laminated veneer lumber with a joist spacing of 450mm. A joist hanger can be used to connect to bearers.

What goes on top of floor joists?

You want to avoid cracking of the grout so applying plywood on top of the joists and then using a cement board underlayment is most ideal for this medium. Laminate – can be installed just like hardwood on top of plywood, but you also will have to add a secondary underlayment of thin plywood.

What are the strongest joists?

Easi-joist® engineered joists – parallel chord trusses using stress-graded timber chords, plated together with Wolf Systems’ patented, precision engineered metal webs, EP 1 985 774 B1- provide the strongest system available on the market.

How long do floor joists last?

Wood floor trusses can be expected to last as long as the home itself (100+ years), if maintained in a stable, reasonabley dry environment. Moisture from excessive humidity, condensation, or plumbing leaks, along with termites are the problems that can shorten a floor truss life.

Who makes TJI joist?

Weyerhaeuser TJI® Joist Floor Framing includes a series of joists made in Canada: Weyerhaeuser Trus Joist® TJI® s31, s33 and s47 joists.

Can TJI joists get wet?

Like all wood materials, I-joists are susceptible to moisture. Avoid unnecessary moisture exposure of all wood components by enclosing the frame against adverse weather as soon as feasible.

What is tji construction?

TJI’s (engineered wood I joists) are my preferred framing members for floor systems. TJI’s offer many benefits compared to traditional dimensional lumber joists including: almost no twisting or warping, very little dimensional shrinkage, stiffness and strength.

How far can a TJI floor joist span?

According to TJI’s span table, switching to deeper 11-7/8 inch joists (a nominal 2×12), even when spaced at 19.2 inches on-center, enable you to go as long as 17 feet, 4 inches and still achieve L/480.

How far can a 11 7 8 tji span?

TJICHORD DEPTH16″ O.C. MAX SPANTJI-2309-1/2″16′ 2″TJI-11011-7/817′ 10″TJI-21011-7/8″18′ 8″TJI-23011-7/8″19′ 2″

What is the most common method of supporting TJI joists?

Photo 1 shows the most common method used to support I-joists from wood beams. The I-joists are set in galvanized steel joist hangers that are nailed to both the beam and the I-joists, with the tops of the I-joists flush with the tops of the wood beams.

Where are LVLS made?

The main raw material used to produce LVL is wood veneer of various grades and it has been used structurally for several years in Northern America and in many European countries. At present, there is only one manufacturer of LVL in Australia – Wesbeam!

Is glulam the same as LVL?

Here, glulam is commonly used for beams in both structural and decorative applications. It has been likened to laminated veneer lumber (LVL) as they are both similar in strength, although glulam offers wider design possibilities because of its aesthetics and a higher level of finish quality.

Is LVL stronger than hardwood?

One of the major differences between LVL and conventional lumber is that – due to the emphasis placed on quality bonding in LVL – there are no naturally occurring knots. This not only makes the product stronger, but more durable than conventional lumber.

Is engineered wood MDF?

MDF is an abbreviation for a type of engineered wood. The full name is Medium-Density Fiberboard. MDF consists of thin panels made from wood fiber, resin and wax. When it comes to engineered wood, MDF is often considered a level above plywood.

Why is engineered wood bad?

Cons of Engineered Wood: Constant exposure to sunlight can warp certain material finishes. Engineered wood cannot be repaired easily and needs to be replaced. Care needs to be taken to not damage the furniture. Low-density engineered wood like particle board can break easily.

What is engineered wood vs MDF?

Engineered wood is a product that has been created in a factory using a mixture of materials such as wood fibres, sawdust, glues and chemicals. The most basic type of engineered wood – MDF (medium density fibreboard) is simply sawdust and fibres held together with glue.

Are I-joists cheaper?

I-beams are increasingly taking over in new residential construction. In new construction, it is cheaper to use engineered joists in some cases. For instance, it is possible to use half the number of I-beams compared to 2x10s since I-beams can span further with center support.

Are I-joists stronger than timber?

Are I joists stronger than timber? … They can span greater distances, and are considered to be 50% stiffer than dimensional timber under traditional frame spacing. Unlike timber, the strength of an I joist is not affected by cut holes that are used to run plumbing.

Are I-joists safe?

I-JOISTS AND FIRE The lumber industry will say that as a protected assembly, following ASTM E-119, Standard Test Methods for Fire Tests of Building Construction and Materials, the wooden I-joists should pose no significant threat.

Can I use 3x2 for floor joists?

NO! 3″ x 2″ joists can only span 1.41 metres when used as floor joists and this is at 400mm joist centres, any further apart and the span must be reduced even further.

Can I use 4x2 for floor joists?

In short, no real builder would use 2×4’s as floor joists. 4×2 timber floor joists on the ground floor have been used for decades but should be no more than 16 inch or 400 mm centres and be supported at no more than 2 metre centres , 6ft or 1.8 m is preferable and practical .