Thermo Radiata Pine

Thermo Radiata Pine

Thermo radiata pine gives you a durable, stable, warm brown cladding timber with no chemical preservative in it at all. Radiata pine (Pinus radiata) is heated to around 212 degrees Celsius in a controlled kiln with steam and almost no oxygen, a process that permanently alters the sugars and moisture behaviour of the cell walls. What comes out is durability class 2, far more stable than the timber that went in, and a rich chocolate brown that runs right through the section rather than sitting on the surface. Grown in New Zealand and Chile and thermally modified in Europe, stocked in our yard for delivery across Ireland in thicknesses from 20 to 65 mm, with FSC and PEFC certified supply available on request. Sold by the cubic foot and priced on enquiry.

Why Thermo Radiata Pine?

The appeal is a combination that is otherwise hard to buy. You get class 2 durability, an indicative fifteen to twenty five years exposed, without treatment chemicals, which matters on projects with environmental specifications and on anything a client will be living close to. You get a dark, even, walnut adjacent colour without stain. And you get stability: the modification cuts swelling and shrinkage substantially, so boards stay put and joints stay tight through Irish weather swings.

Compared with the tropical hardwoods it competes against, it is lighter to handle, easier to machine, considerably cheaper and from a fast growing plantation source. For rainscreen cladding, screens and garden buildings it is often the sensible answer.

Two honest limitations, and both are consequences of the same process. Thermal modification reduces bending strength, typically by a meaningful margin, so this is a cladding and joinery timber and not a structural one. Do not use it for joists, beams or anything carrying load. It also becomes more brittle than unmodified pine, which changes how you fix it.

Installation guidance

None of this is difficult, but the brittleness is real and it is where installers get caught. Pre drill every fixing without exception, keep fixings back from ends and edges by a generous margin, and do not overdrive: a screw run home hard will crush the fibre around the head.

Use A4 grade 316 stainless steel throughout on anything exposed. Build a properly ventilated cavity behind cladding so both faces can breathe, because trapping moisture behind a board defeats the point of buying a stable timber. Seal cut ends before fixing. The modified timber is dark right through, so a cut end matches, but sealing still helps at the detail.

Finishing & maintenance

You have two legitimate routes. Left bare, the brown fades under UV to a soft silver grey over roughly twelve to eighteen months, evenly and predictably, and the durability is unaffected because it is baked into the timber rather than applied to it. Or oil it with a pigmented UV protective oil and hold the chocolate brown, which means recoating every year or two depending on exposure. Most of our customers who choose this timber do so for the colour, so most of them oil it, but silvering is a perfectly good outcome and costs nothing.

Avoid film forming finishes, gloss paints and yacht varnish, which crack and lift on exterior cladding and trap moisture behind the film. A penetrating pigmented exterior oil is the right product and we stock the ones that suit thermally modified timber, so ask us which to pair with yours. For both routes, an occasional wash with warm soapy water and a soft brush lifts algae and keeps the surface even.