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If a large log is sawn to produce a number of beams, they will be a combination of halved and quartered beams and will become cupped or diamond in section when affected by shrinkage. A boxed heart sawn beam will remain quite square in section with most deformation occurring, as dishing on all four faces. Twisting of timbers whilst drying is not common unless the tree was twisted during its’ growth.
Should I treat Oak with preservatives ?
Oak is a very durable timber used in boat and house building for hundreds of years.
Oak has its own natural preservative, The tanins in Oak are unattractive to pest and diseases.
The structure of Oak is so dense that moisture will only penetrate the first 2mm.
What will happen to the Oak if I let it ages naturally?
When the Oak ages, the sun and rain combine to remove tanin from the surface of the Oak
Tanin is brown and as this is lost and the sun bleaches the surface the Oak turns silvery grey.
What should I do if I want to keep the golden colour of the Oak.
There are many micro porous surface treatments in the market, Greenwood Oak would recommend Osmo 410 UV Protect for external Oak as this retains the Oaks natural colour.
Why are there cracks in the Oak?
There are two main types of cracking in Oak, sun checking, this is small cracks caused by the rapid drying of the surface when fresh sawn and exposed to the sun.
The larger cracks are caused by differential drying within the Oak causing stresses which pull the surface apart. Unlike in some species of timber such as softwood,
Oak cracks do not normally join together to cause a weakness. Cracks are a normal and feature in naturally dried Oak - Oak that has been dried quickly is likely to have larger cracks.
Will the Oak move and cause problems with glazing?
Greenwood Oak always use Oak that is sawn to create the most stable section i.e. boxed heart. The timber used for glazing is also air dried for two to three years.
Very little movement is expected in glazed frames, although minimal expansion and contraction will occur seasonally which is common in all timbers.
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