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Types of Timber: All you need to know

If you’re in the building trade, a joiner in particular, or work at Howarth Timber & Building Supplies, you’ll know a great deal about the different types of timber. But there is always something new to learn or types of timbers that you’ve never or rarely worked with.

We thought it would be a good idea to create an “all you need to know” style definitive guide that takes a comprehensive look at all types of timber. Everything from standard CLS timber and PSE timber to detailing the different types of hardwood timber, (be it 4x2 timber, 3x2 timber and 2x2 timber) and the best timber cladding. Right, let’s get started by defining the 3 main types of timber.

Logs of timber stacked up on top of each other. At Howarth Timber, we supply a wide range of timber products.

Major Oak Polishing

The 3 main types of timber

In the UK, we have three key types of timber which are commonly used in construction:

Softwood Timber – derived from evergreen deciduous trees, softwoods include Pine, Spruce, Douglas Fir, Cedar and Larch. These are highly popular because they are not only the cheapest types of timber, they are also easy to work with.

A softwood timber sleeper used in a garden. Durable and hard-wearing.

Brown Softwood UC3u Treated Garden Sleeper 95 x 195 x 2400mm

Hardwood Timber – made from broad-leaved deciduous trees, hardwood timber is dense, durable and perfect for heavy construction work or where a quality finish is required. Wood types include Oak, Ash, Beech, Walnut, Chestnut and Mahogany.

Hardwood timber sleeper used in a garden with flowers scattered around it.

Howarth Timber

Engineered Timber – these manufactured types of wood are made by binding wood fibres and veneers with adhesives. This delivers strength, design flexibility and stability. Types of engineered timber include MDF, Plywood, Glulam, OSB, Chipboard and Laminated Veneer Lumber.

An engineered timber wood floor often used in a lot of British homes.

Howarth Timber

CLS Timber and PSE Timber

You may hear a fair bit of jargon and acronyms thrown about when talking timber. Two of the key ones are CLS timber and PSE timber. If you’ve always wondered what they mean, Howarth Timber & Building Supplies is here to clear up the mystery.

What is CLS timber? CLS stands for Canadian Lumber Standard and usually comes in the form of a softwood such as pine, fir, or spruce. Originally made in Canada, the name actually refers to the process and standard that the timber is manufactured to. So CLS timber can actually be from anywhere – in fact most UK CLS timber is from Europe and Scandinavia. The process involves kiln drying which removes moisture to prevent warping or cracking and it also increases the timber’s strength and durability. It’s mainly used for stud walls, partition walls, studwork, floor joists, roof joists and loft joists.

A man holding a block of CLS timber, which is perfect for roof joists.

@brainfizzuk

What is PSE timber? PSE stands for Planed Square Edge timber. Sometimes also called Planed All Round (PAR) timber, as the name suggests, PSE timber is a softwood that has been machine-cut and planed on all four sides and therefore has no rounded edges. This creates a smooth finish perfect for furniture, shelving, sash windows, decking and flooring. Like CLS timber, PSE timber is kiln-dried to prevent warping and cracking. PSE timber can also be finished with stain, oil, or lacquer to bring out the beauty of wood and protect it. PSE is available in a wide variety of dimensions including standard 4x2 timber, 3x2 timber and 2x2 timber sizes.

PSE timber fence panels, which is available in a wide variety of dimensions.

PSE Timber Joinery UC3u Redwood FSC 20 x 44mm

Timber grades

Within each type of natural timber types, there are several different strength classifications. These individual grades of wood differentiate which types of timbers are suitable for specific uses.

Softwood C Grades – “C” stands for Coniferous. Softwoods like CLS timber comes in a variety of strengths and are graded C14, C16, C18 and C24 – the higher the number, the fewer the knots and the greater its strength. The two most commonly used are C16 and C24 – which is also used for carcassing timber.

Hardwood D Grades – “D” stands for Deciduous. Hardwoods are graded according to strength with the classifications D24, D30, D40, D50, D60 and D70. The higher the number, the stronger the hardwood.

Timber grades are often used to identify different uses of timber. Use class 2, 3u and 4 are the most popular and used amongst Britain.

Howarth Timber

Pressure-Treated Timber

Most timber can be used indoors, but for timber exposed to the elements, pressure-treated timber is a sensible choice. Pressure-treated timber is infused with preservatives to provide a level of protection. This enables it to resist rotting, insect and moisture damage. This is the ideal timber type for decking, fencing and where the timber comes into contact with the ground.

A pressure treated fence panel which is often used to sepate two gardens from each other. Hard-wearing and great in different weathers.

Fence Pailing UC3u Treated Brown Top FSC 19 x 75 x 1200mm

Carcassing Timber

Carcassing timber is timber that has been specially processed for use in structural applications including roof battens, floor joists and studwork for partitioned walls. It is basically the timbers used to build the carcass of a building and is often treated with chemicals to improve its durability, such as preservatives or fire retardants. It is generally less finished than other timbers as it is usually unseen.

Carcassing timber is used often for roof battens, which are often used when crafting a new roof.

Roofing Megastore

Cladding & Fencing Timber

If your project involves cladding either the interior or exterior of a building there are different types of timber cladding to choose from, but the key difference is whether the timber is treated or untreated.

Untreated timber cladding is fine for cladding the interior of a building but if you are cladding the outside, you will need treated cladding timber which is designed to withstand the elements and other enemies of wood.

Fencing timber tends to be treated as it tends to have to withstand the rigors of the Great British climate. There are many different types of timber fencing components available such as fence posts, fence boards, fence panels and fence trellises and screens .

Cladding timber can be used for both interior and exterior buildings.

Loglap UC3u Green Treated Cladding FSC 25 x 100mm

CLS Timber Sizes

Most timbers, including CLS, are available in wide variety of different sizes designed to fulfill all the different demands that joiners and builders have. The typical ones held in stock by Howarth Timber & Building Supplies are 4x2 timber, 3x2 timber and 2x2 timber.

CLS timber come in a wide range of size, such as 3x2 timber and 2x2 timber.

Sustainable Timbers

Sustainability is becoming increasingly important to clients, specifiers, architects and the UK building trade. They demand certified timbers that has been responsibly sourced and modified woods that have longer lifespans. Standards to look for are FSC (Forest Steward Council) Certified timbers and PEFC (Programme for the Endorsement of Forest Certification) timbers which are widely stocked by Howarth Timber & Building Supplies.

Sustainable timber products are becoming widely important amongst the construction industry. PEFC and FSC are the most well-known amongst the enviornment.

Caberdek Chipboard P5 Tongue & Groove Flooring FSC 22 x 2400 x 600m m

Timber prices

Want to know what the cheapest type of timber is? Well, it probably won’t come as a surprise to learn that softwoods are cheaper than hardwoods and that the lower the grade of each, generally, the more affordable they are. Also, engineered timbers such as chipboard, plywood and MDF are also at the lower end of the price spectrum.

Always here to help

If you’ve any questions regarding any of the timber types detailed in this guide, or want any additional information about the timber we sell at Howarth, please visit your local Howarth branch, or contact our customer services on 01472 907051.

You can also explore our range of Timbers here, or you can even visit us in branch for more information.

16th Jan 2025 Simon Anderson

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