Urgent Plastering Problem - Damsel in distress - advice please

owls

trade federation are right about the moist resistant plasterboard these are different from vapourcheck plasterboard, the moist resistant plasterboard are green and are designed for tiling straight onto.

designermatt_2

I have typed this out once already.. but got logged out so it didnt post. To save me doing this over again, this is a shortened version.. Owls.. your 'noddle' as you refer to him is correct. You misunderstand the concept of a vapour barrier. If condensation is to form anywhere, the underside of the plasterboard is the place for it to form, thusly keeping all the moisture in the bathroom. The vapour barrier is intended to stop moisture passing as a vapour through elements of the building fabric. Just because air is warm does not necessarily mean it is humid. Raising air temperature will raise the air's capacity to hold moisture. If the air is in a bathroom though, chances are it will also have high humidity.Condensation will occur when that warm humid air hits a cold element and condenses. The same as windows 'sweating' in the winter. Without any check to the vapour passing through the ceiling and insulation it will condense in your roof space on the roofing felt and roof timbers. This is what caused 'rain' in people's roof spaces in older houses. Pitched roofs nowadays are generally ventilated with either eaves and ridge vents or breathable roofing felt which lets the water laden air out into the atmosphere rather than trapping it in your roof space. The vapour barrier whilst a good idea is not a REQUIREMENT if my understanding of what work you have had carried out is correct. Essentially if you have replaced your ceiling you are carrying out work to a thermal element of the existing bathroom. This will only be renovation of that thermal element as it is only the ceiling and not the entire roof. When renovating a thermal element it is necessary to thermally upgrade that element when its 'U'-value (heat loss rate) is worse that a threshold value. For a pitched roof with insulation at ceiling level, that 'U'-Value is 0.35 W/m2K. This is equivalent to having approximately 100-150mm of glass fibre insulation on your ceiling. If you had this then there is no requirement for an application. If there is no requirement for an application for this work then they can have no requirement for you to do anything, even if it would be a good idea to have had it done. In regards to Owls's '75mm of Kingspan, I assume you are refering to Kingspan rigid phenolic foam board which is coated each side with a foil layer, 75mm of this would not be sufficient in any application in any roof, and is extremely unlikley to be used in a domestic situation at ceiling level.

As far as Building Control are concerned if your surveyor carries on insisting on the presence of a vapour barrier refer him to Sections 54 -57 and Table 5 of Approved Document L1B of the regs and particularly to section 57 Reasonable provision... If he starts talking about Approved Document C ask him to point out the requirement for a building Regs application. If you wish to provide more information about the work carried out I might be able to help you further on this front.

What may be worth doing though is ensuring as one of your posters said earlier, ensuring a good kitchen or bathroom paint is used, silicon sealing around ceiling / wall edges and sealing up any openings in the ceiling for lighting. Additionally a couple of vent tiles on opposite sides of the pitched roof if you can manage it would be useful.

noodle2_2

Vapour check definately does not have to be used and owls my name is Noodle not Noddle, beleive me I'm also glad I dont work for you