Journal

Check framing timber before it joins the site stack

Cabinframe Editorial Desk

When framing timber reaches a cabin site, compare the pack labels and delivery note with the order, check dimensions and visible condition, then take several moisture readings against the specified target. Keep the supplier’s paperwork and record any mismatch before unloading everything into the stack. These checks help catch an incorrect grade, wet or damaged stock, or a shortage while the delivery can still be identified; they do not replace design review or formal lot acceptance. [1] [2] [3]

Start with the order and delivery note

The order is the reference for acceptance. Before unloading, set the order beside the delivery note and pack labels. Match the intended use and member schedule, species or species combination, finished dimensions, lengths, strength class, grading standard, treatment, quantity and any moisture condition stated for delivery. Swedish Wood’s receipt guidance also calls for checking packaging, quantity, dimensions, grade labelling and cleanliness. A delivery note that says only “structural timber” may not be enough to show that each pack is the material the drawings require. [1] [2]

Use the grade mark as identification, not a full inspection

For structural members, look for the grade or strength class and the applicable grading identification required by the order and local product rules. EN 14081-1 sets requirements for visually and machine strength graded structural timber, including how it is marked. It points to EN 14358 for acceptance of a delivered lot. A grade mark therefore identifies how the piece was graded; it does not confirm that the delivery matches the order, dimensions or condition. Do not try to accept or reject a structural member by judging knots or splits against a general rule of thumb. If a mark is missing, unreadable or inconsistent, photograph it and ask the supplier or project designer to resolve the discrepancy before the timber is built in. [3]

Measure dimensions and look for damage

Check a sample of pieces across the packs, including timber near the outside and within any pack opened for inspection. Compare the measured cross-section and length with the ordered size and the relevant tolerance, taking account of whether the order gives nominal or finished dimensions. Look for crushed edges, splits, excessive warp, standing water, dirt and broken packaging. A visible defect does not by itself establish whether a graded member remains suitable: the governing specification and grading limits matter. Set aside pieces with possible structural damage for the supplier or responsible designer to assess. A project specification for the Egham refurbishment says not to use members damaged, crushed or split beyond the limits permitted by their grading. [1] [2] [3]

Take moisture readings that mean something

Moisture content is a project requirement, not one universal pass value. A publicly available specification for a refurbishment in Egham, England, gives one example: structural softwood for joists, purlins and rafters is specified as C16. Timber under 100 mm thick and not specified for wet exposure is to be graded at an average moisture content not exceeding 20%, with no reading above 24%, and marked DRY or KD. Timber intended for higher-moisture installation is marked WET or GRN. The same specification separately limits moisture at installation to 24% where timber will be covered in a generally unheated space and 20% in heated spaces. These requirements belong to that project specification, not every cabin or jurisdiction. [2]

For a useful delivery check, Swedish Wood advises random measurements on a number of pieces using an electrical resistance moisture meter with insulated hammer electrodes. Measure at least 300 mm from an end, insert the electrodes into the face along the grain and 0.3 times the width in from the edge, and measure to a depth of 0.3 times the timber thickness. Record the piece or pack and the reading. In a dispute, Swedish Wood refers sampling to SIS-CEN/TS 12169 and moisture requirements to EN 14298; for a 16% target, its table gives a batch average of 13.5% to 18%, with 93.5% of pieces between 11.2% and 20.8%. The table describes moisture measured into the wood, not surface moisture. A few quick readings indicate whether the delivery appears to match the order; they do not establish lot acceptance. [1]

Record the issue before stacking

If the grade, moisture, dimensions, quantity or condition differs from the order, note it on the delivery record where possible and notify the supplier promptly. Photograph the full pack side, its label or batch number, and the specific fault; record moisture readings and which pieces were checked. Swedish Wood advises making a claim at receipt and keeping the whole pack available for inspection if condition is disputed. As a practical site step, keep questioned timber identifiable so it is not mistaken for accepted stock. Do not use members damaged beyond their grading limits, as the Egham project specification directs. [1] [2]

Protect accepted timber from the next source of damage

Once checked, stack timber flat on clean supports above drained ground, with enough support to prevent bending. Protect it from rain and ground moisture while allowing air to circulate; store it according to its intended use and the project’s moisture requirements. Before the delivery joins the working stack, make sure the record says what was checked, which packs remain under review, and who must resolve the open issue. That gives the next person a clear boundary between material ready for the frame and material still awaiting a decision. [1] [2]

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