September 17, 2015
There is a wide variety of engineered wood products now available on the market such as glue laminated timber, finger-jointed timber and LVL products.
If using these products, reference to specific manufacturer recommendations is required as in most cases there are additional requirements or limits when these are used in applications such as decks where they are exposed to the weather.
LVL/LGL manufacturers only endorse the use of 17C (Pine H3) Beams in weather exposed applications if they have a full penetration treatment are painted, faced with sheeting in sun exposure & the end/top capped.
Further to this they state that the LVL/LGL surface CANNOT be exposed horizontally to weather & that water entrapments are NOT permitted.
Therefore, unpainted or unprotected LVL/LGL Beams, are unsuitable for weather exposed projects.
Please refer to the following downloads for more detailed information:
Checking vs Delamination
Sometimes the identification of “Checking” & “Delamination” can be confused.
What is checking?
Checking is a naturally occurring consequence of the seasoning process of wood e.g. The result of moisture loss & shrinkage during drying.
Checks or splits are identified as separations which extend along the wood grain.
Timber checking usually doesn’t pose any structural problems as they rarely extend through beams to the other side, & glue laminated timber generally shows fewer & smaller checks than solid sawn timber.
Examples of Checking on a 17C LGL Beam
What is delamination?
Delamination is the separation of the individual LVL/LGL laminations & occurs when the glue bond on LVL/LGL is inadequate.
In cases of delamination, the surfaces of the lamination where the separation has occurred, will be smooth & free of torn wood fibres.