Introduction — Why the 1st Floor Decides 90% of Your Comfort (and Headaches)
In a typical Norwegian home, the “1.etg” (first floor/ground floor) carries the biggest load — literally and figuratively. It anchors the building to site and climate, sets the tone for accessibility and fire/life safety, dictates most of the day-to-day comfort (thermal, acoustic, daylight, air quality), and locks in a huge share of your building’s embodied and operational carbon. The choice of how to build the 1st floor is therefore much more than an aesthetic or structural decision: it’s a long-term commitment to performance, durability, health, cost, and regulatory compliance.
This article is your deep, practical guide to choosing and detailing the 1.etg of a standard-size house (think 120–180 m² total floor area). We’ll cover:
- Historical context: How Norwegian ground floors evolved from log sills and crawlspaces to today’s slabs and mass timber.
- Current relevance: What TEK17, accessibility, radon, moisture, energy performance and user expectations mean for the 1st floor today (with references).
- Practical applications: Clear scenarios (slab on ground, crawlspace, basement, hybrid mass timber), how to pick, how to detail, and how to avoid the top 10 failure modes.
- Future implications: Low-carbon materials, bio-based insulation, adaptive reuse, and energy-positive homes; what to plan for now so you don’t repaint yourself into a corner later.
My goal is simple: give you a decision playbook you can apply on a real house in Norway — one that satisfies TEK17, aligns with best-practice building physics, reduces CO₂, and makes for a warm, quiet, healthy home.
Part I — A Brief History of the Norwegian Ground Floor
From stabbur wisdom to ringmur pragmatism
Norwegian building culture long favored raised timber floors on stone piers or shallow foundations to keep timber dry and ventilated. Early houses used massive logs for sills on fieldstones; moisture management was passive (air gaps) and resilient by design. With the spread of sawmills and nails, platform framing emerged, and with it crawlspaces (krypkjeller) — a pragmatic way to separate wood from ground moisture while keeping access to services.
Post-war reconstruction and the rise of concrete brought slab-on-grade and ringmur (edge beams) into mainstream housing. The promise: faster builds, better thermal mass and easy finishes. Meanwhile, the full basement (kjeller) remained popular where topography or program demanded extra space (storage, utility rooms, hobby rooms), or frost heave and slope required deeper foundations.
Today, we see a hybrid renaissance: CLT (cross-laminated timber) and glulam offer warm, fast, low-carbon structures, often paired with insulated slabs or ventilated crawlspaces using better detailing than their predecessors. Add tight envelopes, balanced ventilation with heat recovery, underfloor heating options, and smart moisture design, and the ground floor becomes the building’s healthiest, quietest, and most efficient layer.
Part II — The Regulatory Frame You Must Respect (and Leverage)
Norway’s Byggteknisk forskrift (TEK17) sets the minimum requirements for safety, health, environment, and energy. You don’t need to memorize it, but you must design the 1st floor with a few chapters in mind:
- Accessibility & usability (Kap. 12): For dwellings where the rule applies, main functions must be on the entrance level and the entrance level must be accessible; in multi-storey dwellings the accessibility requirement applies to the entrance level only. Direktoratet for byggkvalitet
- Indoor environment & moisture (Kap. 13): The ground floor is where most radon and moisture risks are born. TEK17 caps radon annual average at 200 Bq/m³ and requires radon barrier and readiness for activation of sub-slab mitigation when indoor air exceeds 100 Bq/m³ action level. Direktoratet for byggkvalitet+1
- Energy (Kap. 14): New homes must meet net energy demand budgets and other energy requirements; compliance is typically demonstrated via NS 3031 methodologies and may require flexible heating supply and heat recovery. Direktoratet for byggkvalitet+2Direktoratet for byggkvalitet+2
Tip: If you are doing work on existing buildings, check the DiBK guide “Arbeid på eksisterende bygg” to determine whether TEK17 requirements apply in full or partially. Direktoratet for byggkvalitet
For existing houses or adaptive reuse, a condition assessment using NS 3424 Tilstandsanalyse provides a common language and method: define scope, plan, inspect, grade condition, evaluate consequences and risk, then report and prioritize actions. Core definitions (tilstandsanalyse, tilstandsgrad, svikt, konsekvensgrad) and the five-phase workflow are standardized.
Consequences (safety, health/environment, aesthetics, economy) are graded, and risk combines likelihood and consequence — a neat way to discuss whether a “small” damp spot is a big problem or not.
Part III — Your Four Main 1st-Floor Archetypes (and When to Choose Each)
We’ll focus on four practical options for a standard-size home:
- Insulated slab on ground with ringmur
- Ventilated crawlspace (krypkjeller) with raised timber/CLT floor
- Full basement (kjeller) with suspended floor
- Hybrid mass timber on insulated slab (CLT plate or timber platform on slab or low plinth)
Each can deliver a great, TEK17-compliant house. The right choice depends on site moisture, radon potential, frost depth, topography, program (e.g., accessible bedroom/bath on entrance level), services strategy, embodied carbon, and budget/time. Let’s compare them.
1) Insulated Slab on Ground (Plate på mark) with Ringmur
What it is: Concrete slab (often low-carbon mix) on compacted drained sub-base, with perimeter insulation and a load-bearing ringmur/edge beam. Services (drains, radon piping, conduits) pass through or under slab. Normally topped with screed/UFH and finish floor.
Best when:
- Site has manageable groundwater and good drainage potential;
- You want excellent airtightness, thermal mass (helpful for comfort), and simpler accessibility (no thresholds);
- A fast build is important and you want easy tile/wood finishes.
Key performance levers:
- Radon: Integrate radon membrane continuous under slab and up to the ringmur. Include sub-slab radon pipe(s) tee’d to a stub in a service room for activation if needed. TEK17 sets 200 Bq/m³ as annual limit and requires barrier + provisions for activation at 100 Bq/m³ action level. Direktoratet for byggkvalitet+1
- Moisture: Capillary break (well-graded crushed stone, ≥150–200 mm), geotextile, perimeter drainage, and careful thermal bridge cuts at slab edges; avoid wet fill and protect sub-base from rain before pour.
- Energy: Edge insulation continuity (min. 200–300 mm of XPS/foam-glass or wood-fiber with moisture management strategy). Ensure overall envelope meets net energy budget under §14-2; verify via energy model. Direktoratet for byggkvalitet
- Accessibility: Slab-on-grade makes TEK17 §12-2 easier to meet: main functions on entrance level, step-free entries and internal thresholds. Direktoratet for byggkvalitet
Pros: Fast, robust, airtight; easy UFH; fewer crawlspace mold risks.
Cons: Less flexibility to modify services later; careful sequencing needed to keep sub-base dry; embodied carbon of concrete (mitigate with low-carbon mixes, SCMs and slim slabs).
2) Ventilated Crawlspace (Krypkjeller) with Raised Timber/CLT Floor
What it is: A ventilated under-floor void with timber or CLT joists/plate spanning from a perimeter beam (ringmur) to internal supports. The void is ventilated to outside. Radon barrier and sub-floor ground cover still needed.
Best when:
- Site has high groundwater or complex terrain, making a dry, continuously insulated slab challenging;
- You prefer bio-based, low-carbon floor structure (timber/CLT) and want service accessibility after completion;
- You plan to route substantial MEP in the floor zone.
Key performance levers:
- Moisture: The Achilles’ heel. Specify robust cross-ventilation, sealed ground membrane, and drainage plan; avoid “dead pockets.” Monitor humidity during first seasons.
- Radon: Even with a ventilated void, you still need radon barrier on ground and a passive radon pipe; otherwise, void leakage can drive radon into the dwelling. TEK17 radon requirements still apply. Direktoratet for byggkvalitet
- Energy: Insulate the floor (underside or between joists/under CLT) continuously, sealing wind-washing with a smart membrane. Model the assembly to comply with §14-2 energy budget. Direktoratet for byggkvalitet
- Accessibility: Slightly higher threshold risk at entries; design ramps/landings to maintain step-free access per §12-2. Direktoratet for byggkvalitet
Pros: Dry, inspectable services; low concrete volume; excellent embodied carbon profile if using timber and wood-fiber insulation.
Cons: Moisture management discipline; risk of cold floors if insulation/air control are imperfect; critter control.
3) Full Basement (Kjeller) with Suspended Floor
What it is: Foundation walls to frost depth, slab at basement level, structural deck for 1st floor above. Gains space for storage/technical rooms or living areas if properly insulated and drained.
Best when:
- Steep sites or zoning allow daylight basements;
- You need program in the lower level (home office, hobby rooms, flexible living);
- You can budget for waterproofing and structural complexity.
Key performance levers:
- Moisture & water: Perimeter drains, free-draining backfill, waterproofing on positive side, capillary breaks under slab; specify compatible systems if below groundwater.
- Radon: Basement spaces are closest to source; ensure radon barrier, sub-slab piping, and sealed penetrations. TEK17 limits still govern. Direktoratet for byggkvalitet
- Energy: Insulate foundation walls continuously (exterior preferred for thermal mass and dryness), protect from soil insects/frost; design to §14-2 budgets. Direktoratet for byggkvalitet
- Accessibility: If the entrance level is above the basement, design the 1st floor as the accessible level per §12-2, ensuring all main functions can occur there. Direktoratet for byggkvalitet
Pros: Valuable extra space; durable technical rooms; excellent acoustics if detailed well.
Cons: Highest cost/risk for water ingress; more concrete (embodied carbon).
4) Hybrid Mass Timber on Insulated Slab
What it is: CLT floor plate as the structural deck, bearing on a well-insulated slab or low plinth, with service chases above the plate. Sometimes the CLT sits on foam-glass or recycled glass aggregate, further reducing concrete.
Best when:
- Speed and precision matter;
- You want the feel and carbon profile of exposed timber;
- You aim for Passive House/near-zero and value construction moisture control.
Key performance levers:
- Air & vapor control: CLT is air-tight but joints must be sealed; detail the air barrier at CLT-wall junctions and penetrations.
- Radon & moisture: Same slab considerations as Option 1, with extra attention around CLT bearing lines (capillary break and membranes). Direktoratet for byggkvalitet
- Energy: Excellent airtightness supports meeting §14-2; pair with high-performance windows and MVHR. Direktoratet for byggkvalitet
Pros: Very low site time, warm materials, tidy services.
Cons: Joint detailing is non-negotiable; availability and cranage planning required.
Part IV — The Decision Framework (So You Pick Once, Correctly)
Step 1: Understand your site and building program
- Hydrology: Where does water go in a storm and in spring thaw? Dig test pits, check seasonal highs.
- Soil & frost: Grain size distribution, capillarity, frost susceptibility.
- Radon: Use regional radon potential maps and plan to test post-occupancy (DSA recommends measurements in frequently occupied rooms, at least one per floor). DSA
- Program: Do you need bedroom and accessible bathroom on the 1st floor? TEK17 §12-2 expects main functions at entrance level where the rule applies. Direktoratet for byggkvalitet
Step 2: Establish compliance targets and trade-offs
- TEK17 moisture & radon: Lock in barrier type, jointing, penetrations, and a sub-slab pipe to activate later if measurements call for it (barrier + readiness are TEK17 expectations). Direktoratet for byggkvalitet+1
- Energy budgets (§14-2): Decide envelope performance targets early and verify with an NS 3031-based energy model. Direktoratet for byggkvalitet+1
- Accessibility (§12-2): Fix door widths, turning circles, step-free entry, bathroom layout on entrance level; it’s much harder to retrofit. Direktoratet for byggkvalitet
Step 3: Weigh embodied carbon vs. robustness and cost
- Concrete is tough, versatile, and moisture-tolerant, but carbon-heavy (mitigate with low-carbon cement, SCMs, slimmer sections).
- Timber (joists/CLT) is light, fast, and low-carbon, but relies on airtight membranes and moisture discipline.
- Insulation: EPS/XPS are common; consider foam-glass or wood-fiber for lower CO₂, but address moisture and compression properties.
Step 4: Detail the top 10 risk points (checklist later)
- Edge thermal bridges, door thresholds, wet-room transitions, slab penetrations, rim joist zones, crawlspace vents, drain terminations, radon pipe routing, MVHR condensate, and exterior grading.
Part V — Three Real-World Scenarios (With Detailing Guidance)
Scenario A — The Robust, Accessible Slab-on-Grade
Context: 150 m² compact two-storey house on a moderately well-drained lot in the lowlands. Family wants UFH, step-free entry, and minimal fuss.
Assembly sketch (from bottom up):
- Compacted crushed stone with geotextile separation; perimeter drain to daylight/sump.
- Radon barrier continuous under slab and turned up at ringmur; seams taped; pipe(s) embedded in granular layer connected to capped stub for future fan. TEK17 sets 200 Bq/m³ limit and expects barrier and activation readiness. Direktoratet for byggkvalitet+1
- Thermal insulation (e.g., foam-glass boards or XPS) at slab + continuous edge insulation.
- Concrete slab (low-carbon mix) with UFH; sawcut joints planned away from thresholds.
- Vapor control/air barrier continuity at wall-to-slab junction.
- Exterior finish grade sloping ≥1:20 for 3 m; capillary break at facade footing.
Why it works: Minimal thermal bridges, excellent airtightness, easiest route to §12-2 step-free functionality, straightforward to meet §14-2 energy budget with good envelope. Direktoratet for byggkvalitet+1
Watch-outs: Protect sub-base from rain; coordinate all slab penetrations (water, sewer, electric, radon) and test airtightness before finishes.
Scenario B — The Bio-Based Crawlspace Floor
Context: Coastal plot with variable water table and rock outcrops. Owners want wood-fiber insulation, CLT floor, and serviceability.
Assembly sketch:
- Ground: graded to sump/drain; 6–10 mil ground membrane taped; radon pipe network below membrane connected to exterior stack.
- Supports: ringmur + interior mini-piers; stainless or composite termite shields where relevant.
- Floor: CLT plate or engineered joists; wood-fiber insulation between/under; wind-tight membrane below; taped seams; fire-stops at edges; controlled cross-ventilation (bug-screened).
- Air barrier: run a continuous interior membrane at the floor-to-wall junction with robust taping at services.
Why it works: Ultra-low carbon, easy service access, warm timber feel.
Watch-outs: Crawlspace humidity and wind-washing; specify periodic humidity sensors and design an upgrade path for mechanical under-floor ventilation if monitoring shows seasonal spikes.
Scenario C — Basement Plus Daylight
Context: Sloped site; client wants workshop, storage, and a quiet office downstairs; main living and accessible bath/bed on entrance level to meet §12-2. Direktoratet for byggkvalitet
Assembly sketch:
- Basement wall: exterior waterproofing with protection board; continuous exterior insulation (mineral-based or foam-glass boards); perimeter drains; free-draining backfill.
- Basement slab: capillary break, radon barrier, sub-slab piping. Radon is prioritized here. Direktoratet for byggkvalitet
- 1st-floor deck: concrete or timber; decouple acoustically from basement.
- Energy: the continuity of insulation up from the footing, across wall, and under the 1st-floor rim is non-negotiable to meet §14-2 budgets. Direktoratet for byggkvalitet
Why it works: Valuable flexible area with superior noise isolation.
Watch-outs: Waterproofing trades coordination; dewatering plan during construction; daylight and ventilation strategy for habitable basement rooms.
Part VI — Building Physics Essentials You Can’t Ignore
Moisture: the invisible destroyer
- Liquid water (bulk): Manage outdoors with overhangs, flashing, grade, and drains; manage indoors with wet-room design, membranes, and robust ventilation of wet rooms, a TEK17 focus area. Våtromskoordinator
- Vapor diffusion & air leakage: Continuity of air barrier is more decisive than the vapor barrier; plan penetrations (sleeves) and pre-tape transitions.
- Capillarity: A capillary break under slabs and at timber bearings is cheaper than any repair.
Radon: design for prevention and easy activation
TEK17 requires the radon barrier and the ability to activate sub-slab mitigation if the home measures above 100 Bq/m³ (action threshold), with a 200 Bq/m³ annual limit. Design the radon piping loop to be accessible (service room) for adding a fan later without demolishing finishes. Direktoratet for byggkvalitet+1
DSA recommends measuring radon in frequently occupied rooms on each floor post-occupancy — plan that into your handover checklist. DSA
Energy: budgets and real performance
TEK17 §14-2 sets a net energy demand budget and additional requirements; compliance often hinges on envelope U-values, airtightness (n₅₀), MVHR efficiency, and hot-water losses. Model the 1st-floor assembly early, and iterate to bring down thermal bridging and infiltration. Direktoratet for byggkvalitet
For many projects, a flexible heating system and avoiding fossil sources are part of the compliance/market expectation landscape. bpie.eu+1
Accessibility and usability
Design for step-free entries, generous turning radii and bathroom clearances at the entrance level. The 1st floor almost always bears this responsibility in practice; locking it in early is the cheapest approach to lifelong usability. Direktoratet for byggkvalitet
Part VII — Materials: Low-Carbon, Durable, and Buildable
Concrete (for slabs, ringmur, or basements)
- Specify low-carbon mixes with supplementary cementitious materials. Slim sections and foam-glass sub-bases can further reduce cement.
- Use thermal break at slab edges and structural thermal breaks at balcony/porch connections.
Timber and Engineered Wood (for raised floors and hybrids)
- CLT floor plates offer airtightness, speed, and a warm finish; detail joints meticulously.
- Laminated joists/I-joists allow deep insulation and long spans, but control wind-washing.
Insulation
- Wood-fiber: Great hygroscopic buffer and low CO₂; keep it dry and wind-tight.
- Foam-glass boards/recycled glass aggregate: High compressive strength, moisture-proof, inert; excellent under slabs and against soil.
- EPS/XPS: Common under slabs; detail to avoid water entrapment and UV exposure pre-install.
Membranes and Tapes
- Select system-tested tapes and membranes; mock-up critical junctions. Your air barrier is only as good as your weakest overlap.
Part VIII — Services & Comfort: MEP That Loves the 1st Floor
- Underfloor heating (UFH) in slabs delivers even comfort and supports lower supply temps (heat pumps love this). In raised timber floors, spreaders or mortars can improve performance and response.
- Ventilation: Balanced MVHR with short, straight runs** reduces noise and boosts efficiency.
- Plumbing: Plan wet room stacks directly above ground-floor wet rooms to minimize horizontal runs in timber floors. Protect pipes from frost near perimeter zones.
- Electrical/ICT: Pre-run conduits across the slab before pour or in a dedicated service layer above CLT; document all routes for future drilling safety.
Part IX — Quality Assurance for New Builds and Renovations
For existing houses or major refurbishments, consider a NS 3424 Tilstandsanalyse to baseline condition, especially for basements and crawlspaces:
- Define scope and reference level (what are we measuring against?).
- Plan: gather drawings and prior reports.
- Inspect & grade condition (tilstandsgrad), document symptoms, and assess consequences (safety, health, aesthetics, economy).
- Assess risk (likelihood × consequence) and propose prioritized measures.
- Report with clear recommendations and costs.
This discipline is priceless when deciding whether to convert a damp basement to living space or to rehabilitate a crawlspace — you’ll distinguish tolerable imperfections from svikt (unacceptable failures) and avoid chasing the wrong problems.
Part X — The Top 10 Failure Modes on 1st Floors (and How to Avoid Them)
- Radon pipe missing or inaccessible → Always include a sub-slab loop to a serviceable stub; test post-occupancy. Direktoratet for byggkvalitet+1
- Edge thermal bridge at door thresholds → Continuous insulation under/around threshold; prefabricated thermal break elements.
- Crawlspace humidity spikes → Cross-ventilation, ground membrane, backup mechanical boost fan with humidistat.
- Slab penetrations unsealed (air/radon) → Sleeve, seal, and photograph every penetration; QA checklist.
- Wet sub-base before pour → Stage drainage, temporary covers, and re-compact after storms.
- Wind-washing of wood-fiber insulation → Wind-tight membrane + taped joints; inspect before closing.
- Wet-room leaks at transitions → System-approved wet-room membranes and drains (TEK17 emphasis on moisture protection). Våtromskoordinator
- Basement waterproofing discontinuities → Positive-side waterproofing with protection board; robust corners; inspection log.
- Non-compliant clearances for accessibility → Lock §12-2 dimensions early; mock-up bathroom and entry. Direktoratet for byggkvalitet
- Energy model mismatch → Iterate envelope and systems to hit §14-2; avoid “last-minute” add-ons. Direktoratet for byggkvalitet
Part XI — Practical Checklists and Process Tools
A. Pre-Design 1st-Floor Checklist
- Site hydrology, soils, frost, radon potential
- Program: main functions on entrance level (if applicable) Direktoratet for byggkvalitet
- Preferred structural system and insulation family
- Energy target (TEK17 §14-2 budgets + comfort goals) Direktoratet for byggkvalitet
- Carbon strategy (low-carbon concrete, timber, foam-glass, wood-fiber)
- Accessibility strategy (entries, thresholds, bathroom layout) Direktoratet for byggkvalitet
B. Design-Phase Detailing Map
- Air barrier continuity at wall-to-floor junctions
- Radon barrier seam maps; sub-slab pipe routing with access point Direktoratet for byggkvalitet
- Drainage and capillary breaks
- Wet-room membrane interfaces (floors/walls) and falls to drains (TEK17 moisture intent) Våtromskoordinator
- Thermal breaks at edges and door thresholds
- MVHR and UFH routing plans
C. Construction QA
- Pre-pour photo log of radon, insulation, penetrations
- Airtightness interim test before interior finishes
- Crawlspace humidity monitoring plan
- Commissioning: MVHR balance, UFH loop checks, radon measurement plan after heating season. DSA
D. Renovation/Adaptive Reuse (NS 3424)
Use the five-phase NS 3424 workflow to size and sequence interventions, grade consequences and risk, and report with prioritized measures & costs.
Part XII — Case Studies (Condensed Patterns You Can Reuse)
Case 1 — The Quiet Family Slab
- Choice: Insulated slab with low-carbon concrete; 250 mm foam-glass under slab, 300 mm perimeter insulation, UFH.
- Why: TEK17 §12-2 access is easy; §14-2 energy budgets met with modest wall/roof upgrades and high MVHR efficiency; strong radon defense from day one. Direktoratet for byggkvalitet+2Direktoratet for byggkvalitet+2
- Notes: Careful threshold detail gives wheel-friendly entry and zero cold stripe.
Case 2 — Timber Lover’s Crawlspace
- Choice: CLT floor over ventilated crawlspace; heavy use of wood-fiber insulation; MVHR with short runs.
- Why: Low embodied carbon, easy serviceability, faster dry-in.
- Risk control: Extra under-floor humidity sensor network and fall-back mechanical ventilation.
Case 3 — Slope Advantage Basement
- Choice: Daylight basement with exterior waterproofing and insulation; 1st floor as the accessible level.
- Why: Adds flexible space; acoustically separated office; energy strategy kept intact via continuous insulation and airtight deck.
- Radon: Emphasis on barrier + active-ready piping. Direktoratet for byggkvalitet
Part XIII — Looking Ahead: What Will Change (and What Won’t)
Materials: beyond concrete and EPS
Expect wider availability of cement-reduced concretes, geopolymer options, and bio-based structural panels. Foam-glass and recycled aggregates will become commonplace beneath slabs. Timber-concrete composites will offer thinner, stiffer floors with reduced cement.
Energy and systems: toward plus-energy homes
Anticipate ever-higher expectations for airtightness, MVHR efficiencies, demand-controlled ventilation, and heat pump integration, with on-site PV and smart controls. Norway’s policy and research landscape continues to push toward energy-positive new builds — your 1st-floor envelope discipline today is the foundation of tomorrow’s near-zero operation. (See TEK17 energy focus and policy context.) Direktoratet for byggkvalitet+1
Health: radon and IAQ vigilance
Radon will remain a permanent design requirement, not a “maybe later.” Integrate design-for-mitigation as standard; schedule post-occupancy testing per DSA advice. Direktoratet for byggkvalitet+1
Accessibility as the default
Norwegian homes are aging with their occupants. Treat step-free 1st floors and generous turning radii as universal design, not minimum compliance. Direktoratet for byggkvalitet
Adaptive reuse and NS 3424 discipline
As carbon accounting tightens, retaining and upgrading existing 1st floors becomes common. The NS 3424 framework ensures objective assessment, consequence grading, and risk-informed prioritization — exactly what lenders, insurers, and municipalities prefer to see.
A Smart, Simple, and Compliant 1st-Floor Specification (Template)
Use this as a starting point to brief your architect/contractor:
- Type: (Pick one) Slab-on-grade / Ventilated crawlspace / Basement / Hybrid CLT on slab
- Radon: Continuous barrier under slab or ground membrane in crawlspace; sub-slab radon pipe loop routed to service room; sealed penetrations; post-occupancy test plan (winter season), per TEK17 and DSA practice. Direktoratet for byggkvalitet+1
- Moisture: Perimeter drain to daylight/sump; capillary break; geotextile; wet-room membranes; MVHR; exterior grade fall away from facade. Våtromskoordinator
- Energy (TEK17 §14-2): Envelope modeled to meet net energy budget; airtightness target set; MVHR efficiency target; UFH design temp and zoning; thermal-bridge catalog. Direktoratet for byggkvalitet
- Accessibility (TEK17 §12-2): Main functions on entrance level; step-free entry; bathroom clearances confirmed during design freeze. Direktoratet for byggkvalitet
- Materials: Low-carbon concrete, foam-glass or wood-fiber insulation where appropriate; CLT/engineered wood where feasible; system-tested membranes/tapes.
- QA/Documentation: Photo log of barriers and penetrations; pressure test before finishes; operations manual with radon test instructions and crawlspace monitoring (if applicable).
- Renovations/Existing: If applicable, perform NS 3424 tilstandsanalyse including consequence and risk grading, with prioritized measures and costs.
Conclusion — The 1st Floor Is a System, Not a Slab
Choosing how to build the 1.etg in a standard-size Norwegian house is a system decision that interlocks site conditions, structure, building physics, services, accessibility, energy, and carbon. There is no one “right” assembly; there is a right process:
- Read the site and program honestly.
- Lock in TEK17 anchors early — §12-2 (access), §13-5 (radon/moisture), §14-2 (energy). Direktoratet for byggkvalitet+2Direktoratet for byggkvalitet+2
- Pick the assembly that best matches hydrology + carbon + constructability.
- Detail the control layers like your comfort and health depend on them — because they do.
- For existing buildings, apply the NS 3424 method to reduce guesswork and prioritize interventions objectively.
Get these fundamentals right, and you’ll have a 1st floor that keeps feet warm, air clean, energy bills low, and future options open — a floor that carries your home for decades with very few surprises.
References
- Byggteknisk forskrift (TEK17) med veiledning — official DiBK portal and sections cited: overview and chapters on accessibility (§12-2), moisture/radon (§13-5), energy (§14-2). Direktoratet for byggkvalitet+3Direktoratet for byggkvalitet+3Direktoratet for byggkvalitet+3
- DSA (Direktoratet for strålevern og atomsikkerhet) — radon measurement guidance. DSA
- Arbeid på eksisterende bygg — DiBK guidance on when TEK17 applies in renovations. Direktoratet for byggkvalitet
- TEK17 energy context — IEA policy brief; BPIE factsheet on energy requirements/flexible heating; English TEK17 energy sections for reference. IEA+2bpie.eu+2
- Wet-room/moisture focus — overview of TEK17 moisture control expectations in wet rooms. Våtromskoordinator
- NS 3424 — Tilstandsanalyse for byggverk — definitions, phases, reporting, consequence and risk grading.
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