I work in a commercial premises. It consists of a large shopfloor area (2500 sqft) with a grid ceiling, with insulation above the grid. The main roof is steel beam construction with wooden rafters. The walls are brick in between steel posts (i struck a wall with a wooden post and it sounded metallic) 
The whole building is about 3500-4000sqft
The backup warehouse area is pretty much the same but with plastic ventilation squares in the ceiling. Why the ventilation? Every room in the backup area (office, canteen, 2 loos, warehouse and a food prep area) has an extraction fan of some variety, but they cant just be dragging air down from the roofspace, surely? Also, why bother with insulation when theres these ventilation squares? Even the toilets are the same, despite the fact that a third of the ceiling is open to the roofspace! When it snows, the snow melts off that half of the roof quicker (theres a solid wall right up to the roof between the shopfloor and the back area)
Also, Above the food prep area, there is no insulation, but there is a solid plasterboard ceiling about 18 inches above the grid ceiling. Is this for fireproofing? (There are two large ovens in the food prep area).
Another thing, looking above the suspended ceilings (through the ventillation), the breeze block walls go up for about 6-8 foot further, about where the external walls end, then theres what looks like white sheets draped from the wall tops to the roof! Whats that all about?
The whole building is about 3500-4000sqftThe backup warehouse area is pretty much the same but with plastic ventilation squares in the ceiling. Why the ventilation? Every room in the backup area (office, canteen, 2 loos, warehouse and a food prep area) has an extraction fan of some variety, but they cant just be dragging air down from the roofspace, surely? Also, why bother with insulation when theres these ventilation squares? Even the toilets are the same, despite the fact that a third of the ceiling is open to the roofspace! When it snows, the snow melts off that half of the roof quicker (theres a solid wall right up to the roof between the shopfloor and the back area)
Also, Above the food prep area, there is no insulation, but there is a solid plasterboard ceiling about 18 inches above the grid ceiling. Is this for fireproofing? (There are two large ovens in the food prep area).
Another thing, looking above the suspended ceilings (through the ventillation), the breeze block walls go up for about 6-8 foot further, about where the external walls end, then theres what looks like white sheets draped from the wall tops to the roof! Whats that all about?
