1. Replaced ceiling in a room (16 x 10 feet) with a flat roof (cold deck), fitted insulation and soundboard. The Owner of 5 Ways appeared on site for a few minutes every few days so failed to realise the roof was vented by a meter long ventilation pipe from the walkway above and put in 3 vents at the front of the room. He emailed to say: "I myself had no idea there was a pipe up there supplying air to this area" - to the astonishment of a structural engineer and 2nd Which? Trader who inspected. Cost one room only: £6387 (minus cost of electrics!). Cost went up every few days. 2. Instead of rectifying the owner directed one of his employees to cut the meter long pipe to 4 inches and left it uncapped, producing a draft to the outside. The original hatch was fully enclosed and draft free. The new hatch does not sit straight, has large gaps, no seals, no insulation and no soundboard thereby negating all the work in the rest of the room. They created a huge draft so the room is freezing. The Owner sent a drawing to say that insulation was unnecessary as it is a warm deck. It is a cold deck that goes straight to a walkway above - 3 of the 4 walls are in fact external. 3. Quality of plastering: crumbles easily, cracks appeared within weeks in coving and on walls in main room (above). 2nd room - approx 6m2 (inc window) - had a total of 19 large cracks in it within weeks for which the Owner wrote to apologise. 4. It took Which? Trusted Traders 13 months (until late December 2019) to pursue the Owner to pay for the remedial work (which does not account for the additional vents he put in as that would require the ceiling coming down again to do it successfully - and which he refused to pay for anyway). Throughout this entire period I have been unable to rent my spare room (losing £750 per month for 19 months). As a result of Covid the remedial work is yet to be done. 5. The two guys that did the work - worked hard, unsupervised, had 2nd evening jobs (as a kitchen fitter and painter) to sustain themselves and one of them started my job having had no prior building experience whatsoever.