Structural Treated Pine H3/H4
Treated Pine for Posts, Pergolas and Retaining Walls
Building a pergola, setting fence posts, or framing an outdoor structure? Treated pine in H3 and H4 covers the range, from above-ground work to timber going straight into the ground. We stock structural F7 sections from 70×35 up to 290×45, GL8 laminated beams from 140×65 to 290×65, H4 eXtreme posts, premium wrapped F7 posts, and H4 garden edging. Whether it is one length for a repair or graded stock for a full build, you get the right treatment level for where the timber sits.
H3 or H4: Where the Timber Sits Decides It
The treatment level comes down to one thing: is the timber in the ground or not. H3 is treated for above-ground outdoor use, exposed to weather but not in soil, which makes it right for pergola frames, cladding, and deck framing off the ground. H4 goes further, treated for direct soil contact and high-moisture conditions, so it holds up as fence posts, retaining wall members, and garden sleepers. Put H3 above ground and H4 in the ground, and the timber lasts the way it was treated to.
F7 and GL8 Structural Grades
F7 treated pine is the workhorse structural section, a balance of strength and flex for wall framing, roof members, and pergola structure. Step up to GL8 where the load or span steps up: it is a high-strength laminated grade built for larger beams, bearers, and heavier outdoor structures. Our premium wrapped F7 KD H4 posts in 90×70 and 90×90 give you a clean, straight post for exposed work, and the H4 GL8 eXtreme posts in 88×88 through 135×135 carry serious load where a structure needs it.
What Goes With It
Fixing structural pine outdoors needs the right screws. Our timber screws for framing and posts handle the connections, with the full screw range for everything else on the build. Carrying load over a span? Step up to LVL beams and engineered timber for bearers and lintels. For framing kept dry inside the building envelope, see our H2 structural pine, or browse the full external treated H3 range for the rest of the outdoor timber.
Serving Sydney Tradies and Renovators
- Trade pricing and bulk lengths: Buy single lengths or by volume at trade rates.
- Delivered to site across Sydney: Sydney, the Blue Mountains, Wollongong, and the Central Coast.
- H3 and H4 structural grades in stock: F7 and GL8 sections, posts, and edging, treated for where the timber sits.
- Australian-owned family business: Western Sydney based. Real people, real stock, real advice.
Whatever the build calls for, above ground or in it, we’ve got the treated pine.
Call 1300 554 775 or request a quote online and our team will help match grade, section, and treatment level to your job.
Frequently Asked Questions
What is the difference between H3 and H4 treated pine?
H3 is treated for above-ground outdoor use exposed to weather, like pergolas and deck framing. H4 is treated for direct soil contact, like fence posts and retaining walls. Use H3 above ground, H4 in the ground.
Can H4 treated pine go in the ground?
Yes. H4 is treated specifically for direct soil contact and high-moisture conditions, which is why it is used for fence posts, retaining wall members, and garden sleepers.
What is F7 treated pine used for?
F7 is a structural stress grade used for wall framing, roof members, and pergola structure, giving a reliable balance of strength and flexibility for treated outdoor work.
What is GL8 timber?
GL8 is a high-strength glue-laminated grade for heavy-duty applications, suited to larger beams, bearers, and outdoor structures that carry serious load or span.
What sizes does structural treated pine come in?
BBS stocks F7 sections from 70×35 up to 290×45, GL8 beams from 140×65 to 290×65, H4 posts from 88×88 to 135×135, and garden edging. Call 1300 554 775 to match sections to your build.