Wooden deck repair cost in Luxembourg (2026)

Callout fixed-fee typically includes:

• Site survey with moisture meter on boards and joists
• Visual inspection of ground screws and joist hangers
• Re-tightening of loose stainless fasteners
• Identification of up to three worst boards for swap
• Written report with photos and scope proposal

A €1 700 HT quote at TVA 17 % invoices at €1 989 TTC; a garden deck stays at 17 % even inside a wider renovation, because the 3 % rate excludes the surroundings.

A sound repair comes after the cause is understood. The most expensive mistake is replacing boards while the underlying structure continues to fail.

The six diagnostic signals:

• Cupping boards (concave surface) — the sub-deck is not ventilated; replacing boards without fixing ventilation repeats the issue in 2 seasons. Solution: open the long edges and oil the end grain.
• End splits on board ends — the decking screw has been set too close to the end or the species was installed too green. Solution: pre-drill and set screws 15 mm from ends; replace only the worst five percent of boards.
• Soft or rotten spots on joists — moisture trapped against the joist by a non-ventilated membrane. Solution: sister-joist reinforcement with a treated C24 beam, add a drip cut and plastic separation.
• Sagging centre of the deck — the plots have shifted or were installed above frost depth (0,8 m in LU). Solution: lift a plank, re-seat the plot to specification, or replace with ground screw. Partial rebuild.
• Wobbly railings and stairs — the mechanical anchoring has loosened; common after 8–10 years. Solution: re-anchor with chemical anchors on a fresh drill hole.
• Surface greying only — no structural issue. A simple wash and oil visit (€8–€14/m²) brings it back.

What should trigger a full rebuild:

• More than 15 % of boards with active rot
• More than three joists with soft spots
• Central deflection over 2 cm on a 4 m span
• Substructure plots below 0,8 m depth or visibly heaved
• Galvanised fasteners throughout (they keep releasing iron oxide into the wood)

A practical threshold: Beyond 60 % of the original substructure needing work, replacement with a fresh substructure (keeping the boards if they are Ipé or sound larch) costs less than repeated patch-repairs over five years. The breakeven is the third successive repair visit in five seasons.

A credible deck repair quote reads like a short medical chart: what is wrong, what is the fix, what is not included and what warranty applies.

Quote should include:

• Cause statement. Short paragraph on what triggered the failure (moisture trap, ageing species, fastener corrosion, substrate movement). Without this, the repair is blind.
• Scope per zone. Deck plan with the affected boards, joists and plots marked, and the proposed fix per zone.
• Materials reference. Species and grade (Douglas C24, Siberian larch AB, thermo-ash Class 1), fastener (A4 stainless 5×60 mm with T25 head), sub-deck membrane (Delta MS 50 or equivalent).
• Access requirements. Whether railings, pergola, planters or outdoor lighting need temporary removal, and who reinstates.
• Duration and waste handling. One or two work days typical for a <20 m² repair, two to four days for joist work, five to eight days for full sub-structure rebuild. Spoil disposal should list the Luxembourg licensed tip (SuperDrecksKëscht or similar).
• Warranty. Two-year workmanship warranty on boards and fasteners, five-year on sub-structure when rebuilt, décennale on structural work.

Usually separate lines:

• Saturator application after repair — €8–€14/m²
• Paint or opaque stain — €14–€22/m² (matches existing)
• Replacement ground screws — €65–€90 each
• Drainage mulch replacement under the deck — €6–€12/m²
• Gate or hatch refit — €280–€650

Red flags:

• No diagnostic statement, only a materials list
• Stainless fasteners in the body but galvanised in the quote (check per-box reference)
• Warranty under 2 years on boards, or a 1-year warranty on sub-structure rebuild
• Full price invoiced at start — normal is 30 % deposit, 40 % on day 1, 30 % on snagging completion
• No commune notification when the scope extends over 50 % of the deck — a déclaration de travaux becomes required

TVA on deck repair in Luxembourg is 17 %. A wooden deck in the garden counts as landscaping around the house (aménagement des alentours), which the 3 % super-reduced rate excludes — for a small repair, a full substructure rebuild or a repair bundled with other works alike. Only a terrace that forms part of the building itself, such as a roof terrace or a balcony, follows the dwelling's 3 % rules.

Rate decisions in practice:

• Stand-alone repair (5 boards and some joists) on a primary residence: 17 %
• Full substructure rebuild of a garden deck on a primary residence: 17 %
• Repair bundled into a wider renovation: the eligible lines of the dwelling can go to 3 % with AED approval; the deck line stays at 17 %
• Repair on a second home, a rental that is nobody's main residence or a commercial property: 17 %

All-in on a €2 200 net joist-and-boards repair:

A quote showing 3 % on a garden deck repair should be corrected before signing.

Deck repair quotes on the same deck can swing by 50 % because different firms interpret "repair" at different depths. Only a shared on-site diagnostic tightens the spread.

The six checks:

• On-site measurement and moisture reading. Each firm should take a moisture reading of boards and joists on the same visit conditions; that reading belongs in the quote.
• Scope-per-zone drawing. A hand-drawn plan of the deck with affected zones marked and the proposed fix per zone.
• Fastener spec. A4 stainless 5×60 mm T25 is the LU standard. Anything less is a false economy.
• Joist protection. After repair, is a sub-deck protection tape (Delta Tape or NMC) specified on each joist top? If not, the next failure follows in 4 seasons.
• Warranty length. Two years on the board swap is the legal minimum; five years on the sub-structure rebuild is the market standard for declared firms.
• Disposal proof. The quote should name the Luxembourg licensed tip used for the old material — a photo of the ticket at the end is normal practice.

A clean briefing pack:

• Photos of the worst three zones with a ruler in the frame
• Year of original construction
• Species of existing boards and joists
• Preferred repair depth (patch, partial rebuild, full rebuild)
• Access constraints (side passage width, height above ground)
• TVA at 17 %, stated explicitly

Three quotes on the same pack land at ±15 %. Wider spreads almost always mean one firm is quoting a patch while another is quoting a rebuild; neither wrong, but they are not the same scope.