What is Free of Heart Centre Timber?

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The importance of Free of Heart Centre (FOHC) timbers is something we are always excited to explain to our clients as we aim to educate them on the materials that we use. 


A Quick Difference Between FOHC & Boxed Heart


To explain it briefly, FOHC means that the heart - or centre - of the tree is not within the dimensions of the timber; it has been sawn in a way to exclude it. Conversely, a Boxed Heart timber contains the centre of the tree within the dimensions of the timber. 


Though there is nothing structurally wrong with Boxed Heart timbers, they are aesthetically inferior to FOHC Timbers for two reasons:

  1. Checking: Because of the radial growth rings in trees, as timbers dry, the outer rings dry at a different rate than the inner rings creating a force within the wood fibers. This tension force causes a check - or crack - in the timber. In general, checking is more prevalent in Boxed Heart timbers than FOHC timbers, because of the larger variation in growth ring size, and as a result, a typically larger tension force between outer and inner growth rings.  
  2. Twisting: This is also attributed to the radial growth rings. As timber dries, it wants to dry from the outside growth ring to the centre of the tree. In Boxed Heart timbers, there is a centre point that the timber will want to shrink around and this can result in more twisting as the timber dries. In FOHC timbers, you get a more even drying process that is less prone to twisting.



Why is FOHC Seen as ‘Premium?’


Simply put, a FOHC timber on average, will provide a more stable timber with less checking and twisting than a Boxed Heart timber. 


When looking for a structure for a home or backyard, our clients want the peace of mind knowing that we’ve used the highest quality materials we can. They can be confident that their FOHC timbers are going to give a better aesthetic over the years than Boxed Heart timbers.


To properly harvest FOHC timbers, they need to be taken out of significantly larger, and older trees. Coincidentally, through sustainable plantation farming, these trees will grow large quickly, so the growth rings closer to the heart will be loose, or far apart from one another. However, as the tree ages, the growth rings will get tighter. As the rings further from the heart of the tree are tighter, the finished, harvested product will have a much cleaner appearance.


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Matt Whittemore
Name: Matt Whittemore
Posts: 3
Last Post: April 22, 2024