NEGROCOMMERC — Trade notes https://negrocommerc.pl/journal/ Technical notes from the NEGROCOMMERC trade desk: wear classes, insulation depths, tiling, partition acoustics and roofing. en-GB Tue, 15 Sep 2026 09:00:00 GMT C2TE S1, decoded https://negrocommerc.pl/journal/adhesive-classes/ https://negrocommerc.pl/journal/adhesive-classes/ Five characters on a bag of tile adhesive, each of them a separate test. Knowing which ones your job actually needs is most of the specification. Dry Mixes Tue, 15 Sep 2026 09:00:00 GMT Measure the wall, not the door https://negrocommerc.pl/journal/adjustable-frames/ https://negrocommerc.pl/journal/adjustable-frames/ Nine door problems out of ten are a casing problem. Here is what to record before the order goes in, and why the answer arrives three weeks later than you think. Doors & Joinery Tue, 08 Sep 2026 09:00:00 GMT Concrete, clay or steel: what the roof actually decides https://negrocommerc.pl/journal/concrete-clay-or-steel/ https://negrocommerc.pl/journal/concrete-clay-or-steel/ The covering is chosen on appearance and then constrained by three numbers — dead load, minimum pitch and what is on the ladder. Roofing & Façade Wed, 26 Aug 2026 09:00:00 GMT AC4 or AC5: what the wear class is actually telling you https://negrocommerc.pl/journal/ac4-or-ac5-laminate/ https://negrocommerc.pl/journal/ac4-or-ac5-laminate/ The number on the pack is an abrasion test, not a durability rating. Here is what it predicts, what it does not, and where the money is better spent. Flooring Wed, 12 Aug 2026 09:00:00 GMT WT 2021 in millimetres: what the U-values mean on site https://negrocommerc.pl/journal/wt-2021-insulation-depths/ https://negrocommerc.pl/journal/wt-2021-insulation-depths/ The regulation is written in W/m²K. Nobody orders in W/m²K. These are the depths that actually get you there, per material. Insulation Fri, 24 Jul 2026 09:00:00 GMT Above 60 × 60, everything changes https://negrocommerc.pl/journal/large-format-tile/ https://negrocommerc.pl/journal/large-format-tile/ Large-format porcelain fails in ways small tile does not. Adhesive class, substrate tolerance and handling are the three that cost money. Tiles & Stone Tue, 30 Jun 2026 09:00:00 GMT Getting a partition to 47 dB without doubling the stud https://negrocommerc.pl/journal/partition-to-47db/ https://negrocommerc.pl/journal/partition-to-47db/ Acoustic performance in drywall is mostly about mass, decoupling and sealing. Two of the three cost almost nothing. Drywall Fri, 05 Jun 2026 09:00:00 GMT Why tile from two pallets does not match https://negrocommerc.pl/journal/batch-and-calibre/ https://negrocommerc.pl/journal/batch-and-calibre/ Calibre and shade are printed on every box and read by almost nobody. They are the single most common cause of a re-tile. Tiles & Stone Mon, 18 May 2026 09:00:00 GMT Sequencing an ETICS façade in one season https://negrocommerc.pl/journal/etics-in-one-season/ https://negrocommerc.pl/journal/etics-in-one-season/ Render systems are weather-dependent at four separate stages. Getting the order right is what keeps a façade off the following spring. Paints & Coatings Wed, 22 Apr 2026 09:00:00 GMT