SSurplusBuilder.
B-grade surplus insulation & plasterboard — Rockwool RWA45 50mm slabs (30 packs · ≈90m²) — CardiffB-grade Job lot

Rockwool RWA45 50mm slabs (30 packs · ≈90m²) — Cardiff

Cardiff·30 packs · ≈90m²·Listed 28d ago
£510/lot

Sold by Cardiff Urban Reclamation (Demolition) · Ref L0441

Contact sellerHow buying works

Condition grade 7/10 (B-grade). Assessed by the seller at listing; figures below relate to this specific lot of 30 packs · ≈90m².

About this lot

Acoustic mineral wool slabs. Packaging slightly creased, product immaculate. Ideal for studwall sound insulation. Located in Cardiff — collection or arranged regional delivery available. Fresh to market — posted 28 days ago by Cardiff demolition Cardiff Urban Reclamation.

Surplus stock like this exists because projects over-order to avoid downtime — the saving gets passed to you instead of the skip. B-grade pricing reflects cosmetics, not performance — the defect notes below set out exactly what was downgraded and why.

Measurements & specifications

Density
45 kg/m³
Thickness
50mm
Location
Cardiff
Ref
SB-43-11
Quantity / lot size
30 packs · ≈90m²
Thermal conductivity
λ 0.027 W/mK (per facing print)
Board squareness
Checked diagonal-to-diagonal on 8 sample boards
Edge profile
Square edge
Storage
Flat-stacked, dry, off the ground since arrival
Facing condition
Foil/paper facings intact on 95% of boards

Condition report & known defects

7/10
  • Facing scuffs and 4 dented edges per pack; thermal performance unaffected.
  • Each unit inspected and photographed on request before dispatch.

Carbon & sustainability notes

No reuse CO₂ credit is claimed on this lot: it is unused stock, so the embodied carbon was committed at manufacture. Buying it still prevents waste — material sent to landfill or energy recovery delivers none of its embodied value.

Reuse is the single fastest way to cut a build's embodied carbon — substitution beats offsetting every time.

Collection & delivery

  • Collection from the seller's Cardiff premises — car/van accessible, assistance with loading provided.
  • Regional pallet delivery can be arranged from £35 depending on postcode and lead time.
  • Inspection before purchase is encouraged — bring a tape and check sample units against the measurements above.

Typical applications

  • Acoustic upgrades between floors
  • Warm roof build-ups and rafter-level insulation
  • Floor insulation under screed or chipboard
  • Dot-and-dab and stud-wall drylining

Questions about this lot

Do part-sheets affect building control sign-off?+

No — what matters is the declared lambda value and installed thickness. Keep a facing photo showing the print line for your Building Regs file.

How should boards be stored on site?+

Flat, dry and off the ground. PIR facings degrade with prolonged UV exposure, so keep the wrap on until the day of fixing.

Is mixed-brand insulation OK in one roof?+

Yes, provided each zone's U-value calc uses the correct lambda for the board actually installed there. This lot is single-brand across all 9 packs.

More surplus insulation & plasterboard

View all →