Snekkermester common mistakes
Snekkermester · Understand the traps and how to avoid them.
When calculating a fall on a roof or terrace, the candidate subtracts the fall over the full length instead of calculating the height of the fall relative to the horizontal projection, and forgets to convert percent fall to a ratio (e.g. 1:60 vs. 1.7 %) before finding the height difference.
The fall requirement is given in different units in different sources (%, mm/m, ratio), and the candidate mixes them or applies the fall along the slope length instead of the horizontal projection. Under time pressure they skip drawing the triangle and calculate directly from the plan dimension.
What to do instead
Always set up the triangle: horizontal projection L, fall i in the same unit, height difference h = L · i (converted to a pure ratio, e.g. 1:60 → 0.0167). Write the unit on every intermediate line, and check that the answer is plausible (a few cm, not tens of cm). Practice 10 mixed-unit conversions before the exam.
The candidate chooses a load-bearing beam dimension or span from experience/table without checking bending moment, deflection (L/300 or L/400) and shear, and without documenting the load assumptions (permanent load, live load, snow, point load).
Table-based sizing feels safe and fast, and the candidate does not distinguish between characteristic and design load, or forgets load factors and material partial coefficients. Deflection is often the governing criterion for long spans, which is overlooked.
What to do instead
Do a full hand calculation in a fixed template: load collection → characteristic load → design load (with γ factors) → moment/shear → capacity check → deflection check. State the deflection limit explicitly and show that it is met. Never present a dimension without the calculation behind it.
The candidate specifies a wood species or panel product without checking strength class, moisture content at installation, durability class against use class (especially exposed cladding and ground contact), and whether the product is treated/coated for the actual exposure.
Product names and marketing terms are confused with technical properties, and the candidate does not link use class (UC 2/3/4) to durability class and treatment. Moisture content at installation is forgotten because it is not visible on the drawing.
What to do instead
For every material choice, write four lines: strength class, moisture content at installation, use class/durability class, and surface treatment/maintenance interval. Justify the choice against the actual exposure (sheltered, exposed, ground contact, fresh water).
The candidate places a vapour barrier on the wrong side of the insulation or draws it continuous through a junction, without showing how it is connected to the window frame, the floor slab and the penetration, and without a wind barrier/vents behind the cladding.
The vapour barrier is drawn as a single line on the plan and the candidate does not think in 3D at junctions. They also mix up the function of vapour barrier (inside) and wind barrier (outside), and forget that two vapour-tight layers create a trapped moisture zone.
What to do instead
Draw the full wall section with numbered layers and arrows for diffusion direction. At every junction, sketch the connection of the vapour barrier with overlapping tape and clamping. State explicitly that there is only one vapour barrier, on the warm side, and that the cladding has a ventilated cavity.
The candidate calculates U-value as a simple area-weighted average without correcting for thermal bridges (repeat bridges, joints, fasteners, corners) and without distinguishing between the calculated U-value and the actual energy frame in the regulations.
The formula for a layered wall is simple and tempting, while thermal bridge correction requires the candidate to know ψ-values or a simplified correction factor. They also confuse the building's total energy need with the U-value requirement of the individual building part.
What to do instead
Calculate the layered U-value first, then apply a documented thermal bridge correction (or a conservative percentage) and state it. Keep the two requirements separate: maximum U-value per building part and total energy frame (kWh/m² per year). Show both in the answer.
The candidate answers fire questions with a single number (e.g. R 30 or EI 60) without stating the building class, the fire section, which side the fire exposure is on, and whether the requirement applies to insulation, integrity or load-bearing capacity.
Fire classes are memorised as isolated labels, and the candidate does not connect them to the building's risk class, number of storeys and use. They also forget that load-bearing structures have R, separating structures have EI, and that the requirement can differ for the two fire sides.
What to do instead
For every fire answer, write the full chain: building class/risk class → fire section → function of the building part → requirement designation (R/E/I) and time → documentation (test/assessment). Never answer with a bare number.
The candidate describes a safe site solution in general terms ("good scaffolding", "HMS is taken care of") without naming the specific measures, responsible role, order of work, and documentation required in the safety plan, and without identifying the risk before the measure.
HMS questions look like common sense, so the candidate writes what sounds sensible instead of what the regulations require. They do not use the risk-assessment structure (hazard → consequence → probability → measure → responsible → follow-up).
What to do instead
Answer in a fixed structure: hazard, who is exposed, probability/consequence, measure at source, personal protective equipment as last barrier, responsible role and date. Tie the answer to the specific work operation (roof work, lifting, excavation, work at height).
The candidate calculates the price of a tender from unit prices without adding spill/waste, time for rigging and cleaning, risk margin, and without checking that the quantities in the bill of quantities match their own take-off from the drawings.
The candidate treats the bill of quantities as correct and copies the quantities, and forgets that spill, waste and indirect costs must be distributed over the items. Under time pressure they skip the control calculation and the risk assessment of the items with uncertain quantity.
What to do instead
Do your own take-off of the 3–5 largest items and compare with the bill of quantities; note deviations. Build the price as material + spill + labour + rigging/indirect + risk + margin, and show the calculation for at least one item. Mark items with uncertain quantity and price them with an explicit risk addition.
The candidate refers to "the regulations" or "the standard" without naming the specific provision, and confuses the Planning and Building Act, the building regulations (TEK/SAK), the guidance (veiledning) and the Norwegian standard when justifying a solution.
The candidate has read the requirements as summaries and does not know which document is legally binding versus guidance. They therefore cite guidance as if it were law, or a standard as if it were a regulation.
What to do instead
Learn the hierarchy: Act → regulation → guidance → standard/industry norm. When you cite, name the document and section, and state whether it is a requirement or a recommendation. For every practice question, write which document level the answer belongs to.
The candidate answers business/economics questions about calculation, tender strategy and contract with general phrases about profitability, without calculating contribution margin, break-even, hourly rate or cash flow effect, and without linking the answer to the contract form (NS 8405/8406/8407) and the distribution of risk.
The economics part is perceived as "soft" and is answered with words instead of numbers. The candidate does not know the difference between fixed price and unit price contract, and forgets that the choice of contract form changes who bears the risk of quantity changes and delays.
What to do instead
Practice a small set of calculations until they are automatic: hourly rate with overhead and margin, contribution margin, break-even, cash flow with payment terms and retention. For every contract question, state the contract form, who bears which risk, and what it means in kroner for the project.