Truss roof attic flooring in Ireland (structural & load guide).
Over 80% of Irish homes built since 1975 have prefabricated W-shaped gang-nail roof trusses spaced at 600mm centres.
Here is what homeowners in modern estates need to know about truss roof load limits, board span ratings and safe installation.
Free, no obligation. One local attic flooring specialist prices your job, not five.
- 600mm CentresStandard Irish truss spacing
- 25 kg/m² + 90 kgEurocode 5 / BS 5268 loft allowance
- 18mm P5 T&GStructural load-spreading deck
- €60–€90/m²Truss-notched raised boarding
2026 Irish Price & Specification Table
Truss roof vs cut-rafter roof in Irish homes
How to tell which roof structure your house has in 10 seconds when you open the attic hatch.
| Job / Package | Typical 2026 Price | What Is Included |
|---|---|---|
| Raised loft boarding + Stira stairs package (15–25 m²) | €950 to €2,400 | Our most popular 1-day package: 270mm XL Loft Legs over 300mm mineral wool, 18mm P5 T&G chipboard deck, and insulated folding timber attic stairs. |
| Raised attic flooring on Loft Legs / XL Legs (supply & fit) | €55 to €85 a m² | Elevates the floor 175mm–300mm above ceiling joists so 300mm quilt insulation stays uncompressed and SEAI BER ratings are protected. |
| Structural timber counter-batten raised deck (175×44mm) | €70 to €105 a m² | Cross-battened C16 treated timber joists fixed perpendicular to ceiling ties for heavier storage loads and older cut-roof attics. |
| Standard T&G boarding directly onto deep joists | €42 to €62 a m² | Only suitable where ceiling joists are already 250–300mm deep or where rafter insulation is used instead of joist wool. |
| Stira-style insulated folding timber attic stairs (supplied & fitted) | €350 to €650 | EN 14975 3-section folding pine/beech ladder (150kg–160kg rating), insulated airtight trapdoor (U-value 0.55–0.85 W/m²K) and architrave. |
| Attic hatch enlargement, relocation or new opening | €180 to €340 | Trimming ceiling joists, fitting double timber trimmers, plasterboard making-good and draught-proof perimeter seals. |
| Heavy-duty concertina aluminium loft ladder (narrow landing) | €520 to €850 | Die-cast aluminium scissor ladder for tight box-room landings or high floor-to-ceiling heights up to 3.3m. |
| LED loft batten tube light + pull-cord/landing switch | €95 to €180 | 4ft or 5ft 18W–36W daylight LED vapour-proof batten wired to your upstairs lighting circuit. |
| Safety grab rail / timber hatch balustrade & eaves shelving | €140 to €320 | Perimeter handrail around the open hatch plus raised side-truss shelving bays. |
Technical Breakdown
Four golden rules for boarding a trussed attic
Rule 1: Never cut, move or notch a truss member
Prefabricated fink trusses use 35×75mm or 35×97mm bottom chords held together by galvanized nail plates. Cutting even a single diagonal web causes immediate ceiling sagging and invalidates structural home insurance.
Rule 2: Use 18mm P5 T&G glued in brick-bond
Because trusses sit at 600mm centres (wider than traditional 400mm joists), thin 12mm boards or Square-Edge OSB will flex. 18mm P5 tongue-and-groove loft panels glued along all 4 edges act as a continuous diaphragm, spreading foot weight across three or more trusses.
Rule 3: Precision notching around diagonal webs
To widen the usable floor beyond the central V-bay, installers scribe and notch the outer T&G panels snugly around the diagonal timber struts and add truss-mounted shelving between the webs.
Rule 4: Keep heavy items near internal load-bearing walls
Place heavier boxes above the central spine wall (between the front and back bedrooms) where the truss bottom chord is supported from below, and keep lighter seasonal items toward mid-span.
Calculate your attic flooring & stairs cost
Two taps: pick your approximate loft area and whether you need raised boarding over insulation, a Stira stairs package, or both.
Your attic area × our 2026 Irish price guide
€1,480 to €2,320
20 m² at €55–€85/m² plus €380–€620 for the insulated folding attic stairs & draught-proof hatch.
- Raised Loft Legs keep 300mm mineral wool uncompressed so your BER rating and SEAI grant compliance are protected.
- All panels are 18mm P5 moisture-resistant tongue-and-groove loft chipboard fitted in 1 day.
How this estimate is worked out
Our calculator multiplies your floor area by 2026 Irish supply-and-fit rates: €55–€85/m² for raised loft boarding on 175mm–300mm Loft Legs over mineral wool, €70–€105/m² for structural counter-battened decks, plus €380–€650 where an EN 14975 insulated folding attic stairs is included.
Get a free quote for your attic floor & stairs
Four quick taps and your number. Your request goes to one local attic flooring & loft boarding specialist covering your county, who rings you back with a fixed written price.
Truss Roof Attic Flooring questions answered
Will Loft Legs work on narrow 35mm truss joists?
Yes. Genuine Loft Legs and XL Loft Legs have a contoured base engineered specifically to straddle 35mm-wide trussed rafter bottom chords and fix securely with two 40mm woodscrews.
Why can't I just lay loose plywood sheets across my trusses?
Loose sheets rocked on top of insulation or unglued across 600mm truss spans concentrate point loads onto a single 35mm chord, crack plasterboard ceilings below, and squash the mineral wool underneath.
Can a folding attic stairs fit between 600mm trusses?
Yes — standard Irish truss spacing is 600mm centre-to-centre (leaving a ~565mm clear gap between timbers). Manufacturers make 550mm-wide insulated folding stairs specifically so they drop straight between two trusses without cutting a single roof member.
What if my new-build attic has airtight membrane on the ceiling?
In A2/A3 BER homes built since 2019, the vapour-control / airtightness membrane sits on the warm side of the ceiling joists. Installers fix Loft Legs into the top face of the joists above the membrane so the airtight seal is never punctured.
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Get a free quote for your attic floor & stairs
Four quick taps and your number. One local attic flooring & loft boarding specialist covering your county rings you with a fixed written price. Nothing is booked until you accept it.