UC4

What Is UC4 Timber?

UC4 (Use Class 4) timber works perfectly for outdoor projects where the wood comes into direct contact with the ground or faces constant exposure to moisture. Builders regularly use it for fence posts, decking frames, retaining walls, landscaping, and other heavy-duty exterior timber structures.

Because the treatment process protects the timber against rot, fungal decay, and insect attack, UC4 timber delivers excellent long-term outdoor durability. At Allen and Orr, we supply quality UC4 treated timber for both trade and domestic customers across Chesterfield, Sheffield, Derbyshire, and surrounding areas.

How UC4 Timber Is Treated

Kiln Dried

Manufacturers first kiln dry the timber to reduce moisture levels and improve preservative absorption throughout the wood.

Pressure Treated

Next, specialist preservatives penetrate deep into the timber under high pressure. As a result, the timber gains stronger protection against moisture, decay, and insect damage.

Incised Timber

In addition, some UC4 timber features small surface incisions that help the preservative treatment reach deeper into the timber for improved durability and performance.

Common Uses for UC4 Timber

• Fence posts
• Decking joists and frames
• Retaining walls
• Raised garden beds
• Landscaping projects
• Outdoor structural timber work

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