What is a voorloef?
A voorloef is a traditional timber joint between two crossing beams, in which the lower, load-bearing beam has a notch on both sides into which the upper beam fits exactly. The joint is described in old trade books on timber construction and in the standard Dutch dictionary of building history by Haslinghuis and Janse.
Loef and voorloef
With an ordinary loef (a cogged or notched joint), part of a beam is sawn away across its full width, so that the other beam drops into it or over it. With a voorloef, the notch does not run across the full width: part of the timber is left standing in the middle. That is where the name comes from.
Because the upper beam hooks into the notches on both sides, it cannot slide sideways or pull out of the joint. A voorloef therefore offers a great deal of resistance to pulling and lateral forces.
Applications
- In old timber floors, common joists are often notched over the main beams (Dutch: moerbalken). In that case, part of both beams is sawn away across the full width.
- The voorloef was used where the joint also had to resist sliding, for example with crossing beams in roof structures and timber-frame constructions.
Tips for restoration
- A loef or voorloef weakens the lower beam at that point. In a sagging floor structure, it is therefore a place to check carefully.
- When replacing, make the new joint from the same timber species and comparably dry timber, so that the joint does not come loose due to shrinkage.
- For listed monuments, repair using the original jointing technique is preferred; consult the heritage adviser.
Related terms
- Main beam (moerbalk)
- Timber floor structure
- Timber joints
- Lap joint
- Timber frame
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