There are major changes happening with the supply of H3 rougher header (unprimed) treated pine.
Traditionally in Australia most H3 rougher header treated pine has had a CCA preservative treatment and been structurally rated F7 (or F5 in some wider sections). Very soon Australian manufacturers will only be producing H3 treated pine that has a LOSP treatment and is structurally rated MGP10.
As a result NHS, will also make this change following a transition period. Initially NHS may stock a mixture of F7 and MGP10 structural rating in CCA treatment. Later we will also move to the new treatment, though we will give you more information about that change at the time.
What is the difference between F7 and MGP10 structural rating?
F7 is a visual stress grading system and MGP10 is a machine stress grading system. There are no hard and fast rules as to what is superior to the other in terms of spans. Refer to the current Australian Standard AS1684 span tables for each structural rating. NHS staff in-store may also be able to assist with span information.
Each length of timber has its structural rating stamped on it. The wider sections (240mm and wider) that are currently F5 are expected to remain F5. Treated pine posts are expected to remain F7. H2F framing pine (blue pine) is already MGP10 graded.
If you have any questions about this change, please don’t hesitate to contact us.