What is engineered timber?

What is engineered timber?

There are no silly questions, so let’s start at the beginning.

When people talk about engineered timber or engineered wood, there’s a big range of products they could mean.

As a generalisation, ‘engineered’ means the wood has been manufactured or specifically re-purposed for use. In our industry, this work increases your options when specifying timber for construction projects.

Most commonly, solid timber sections, wood strands, sheets or particles are bound together with glues or fixings to form larger sheets and beams.

Is engineered timber real wood?

Absolutely. The same softwood or hardwood timber is used to manufacture engineered timber.

It all includes wood to a varying degree – but the glue content of chipboard for example will be much higher than the ratio of glue to wood for glulam beams – you’ll get a different look and feel depending on which you use.

Is engineered timber as strong as solid timber?

Strength is an interesting one as engineered timber is often stronger. This is because the sections of wood can be joined in a way that strengthens their structure. You can also work with just the knot-free sections to remove possible weaknesses.

It is important to note that engineered timber products should be made in a controlled process that guarantees the strength of the product, especially if being used structurally.

Is engineered wood good to work with?

In terms of carpentry work, glulam is very similar to the timber it is made from. However, some engineered timber products with a higher glue content can be harder to machine.

Engineered timber increases your design possibilities. Put simply, you’re not limited by the size of the tree you’re getting timber from, meaning you get flexibility on the size, shape and scope. You can also manipulate the timber to achieve variety in shape and form, which you can’t do on quite the same scale as timber in its natural form.

When it comes to glulam, you define what you need, and Buckland Timber designs, engineers, and manufactures the glulam to suit.

Different Types of Engineered Timber

Choosing between different types of engineered timber depends on your project. Here are some of your options.

Glulam:

How is glulam made?

Glue laminated timber (known as glulam) is made by bonding smaller layers of wood, usually 30-45mm thick planks, together using a durable, moisture-resistant structural adhesive.

Glulam lets you manufacture timber elements not easily sourced in solid timber due to their large size or unusual shapes. You’re left with a larger, single component you’d never get in a solid timber.

What is glulam used for?

Glulam beams are an eco-friendly replacement for steel and concrete structures in buildings. Their beautiful aesthetic means the structural beams are often left exposed as a feature of the building design.

Buckland’s engineering lets us manufacture curved beams and structural beams for large projects… glance up at your local community centre, school or swimming pool and you’ll probably clock some engineered timber.

Softwood options include spruce and redwood, while hardwood oak and ash are also available. Some timber, like Douglas fir and larch can be treated for use externally, so the key for you is to find experts to guide you.

Curved Glulam Beam in Carpentry at Buckland

Cross-Laminated Timber (CLT):

How is CLT made?

When we talk about CLT, think wood panelling products. Similar to glulam, it’s made from glueing layers of solid-sawn timber together.

During manufacture, each layer of timber is oriented perpendicular to the next layer and bonded together with glue.

What is CLT used for?

You see this engineered timber used in construction projects for large-scale floor or wall panels. CLT is like plywood, but the right angles make the panels thicker and very strong, even when reaching up to 20m in length.

CLT panels can made to fit very detailed specifications. We tend to deliver panels with all machining complete, including holes for servicing and openings for windows and doors.

Seed processing facility – spruce glulam and CLT

Thermally Modified Timbers

How is thermally modified timber made?

Here, temperature is used to change the internal structure of the wood. Incredibly high temperatures are used to heat the timber, but oxygen is removed so it doesn’t burn (remember the fire triangle from those science lessons!).

This chemical-free process modifies the timbers’ characteristics on a cellular level to enhance durability and stability, ensuring excellent performance even exposed to the elements.

What are thermally modified timbers used for?

Modified timbers are more durable than traditional untreated hardwood. British grown woods like ash, poplar, and sycamore can be transformed into durable timber for outdoor use, including external cladding.

Modifying the timber can be a way of turning cheaper non-durable timber into very durable timber. Vastern Timber’s thermally modified wood is known as Brimstone, and UK Hardwoods are excited to offer their valued customers this versatile, time-tested product using Grown in Britain certified wood.

Community Roots Cornwall Project using UK Hardwoods’ Thermally Modified Ash

Structural Insulated Panels (SIPs)

How are SIPs made?

Have you seen more mention of construction projects using SIPs on your phone’s feed recently?

SIPs panels have an insulating foam core, sandwiched between outer layers. These facings are often made from Oriented Strand Board (OSB), which are a strong combination of wood strands and glues.

The outer layers are bonded to the insulation core, making them structurally sound and construction ready.

What are SIPs used for?

SIPs might be an interesting option for you, as bonding the layers together in this way makes the panels strong for walls and partitions. The lightweight design makes them cost-effective and easy to work with, and the insulated core makes them energy efficient. But here’s the real kicker… they can be manufactured to almost any building design.

If your project involves SIPs, Buckland Timber can work with you to manufacture the glulam you need. For a cabin project in France, we designed and supplied GL24 glulam to bring the whole SIPs construction together.

SIPS Cabin Project, France

I-joists

How are I-joists made?

I-joists are made using a top and bottom flange of profiles timber, connected either with an OSB web (see above) or lightweight metalstrutting

With our particular skills in creating curved beams, we have made several curved I-joists for building projects. Straight I-joists we would usually source from suppliers such as James Jones.

What are I-joists used for?

I-joists are used a lot in floors and roofs, especially in residential buildings.  This is because they are good for long spans and are quick and easy to install. They are stiffer, lighter and easier to manoeuvre than solid timber joists.

Curved I beams – CNC cut OSB board with curved top and bottom glulam flanges

Laminated Veneer Lumber (LVL)

How is LVL made?

LVL is like plywood, but formed of very thin veneer-like layers of timber into beam shapes. It can also be manufactured into thicker sheets to be used as a flooring, columns or roofing material.

The strongest product on the market to our knowledge, is Baubuche, manufactured by Pollmeier. It is essentially LVL made from very strong beech veneers.

What is LVL used for?

LVL is typically used for beams, lintels, purlins, truss chords and formwork. We have used LVL in the past, mainly where it is used alongside glulam for a design, but we often alter LVL designs we receive to allow us to use glulam instead.

This is not because glulam is better necessarily, it is more a matter of sourcing the material. The sizes of LVL kept in stock in the UK can be limited, so it is best to check this when designing with LVL.

Hybrid beams made of Glulam, LVL, CLT and steel

Other sheet materials

There are several other engineered timbers which come under the loose heading of ‘sheet materials’.

OSB (Oriented Strand Board) we’ve mentioned already. Chipboard and MDF we don’t particularly use, but we have increasingly used plywood as part of a few project designs – most recently in the flooring for the Old Vic Theatre in London’s South Bank. (Read all about the project in RIBA’s The List, pg 154)

Buckland Timber are expert manufacturers of engineered timber, so whatever material you’re considering for your next build our team of engineers, carpenters, architects and project managers are ready to guide you all the way through from your design to your perfect build, simply get in touch!