what insulated plasterboard should i use..

[carlramsay]

Hi,
I have a problem in my daughters room, when it gets cold there is a build up of damp on the wall. This is due to the fact one of the external walls is solid block, the other is cavity and the other 2 are internal, obviously the damp is on the solid wall. this is not rising damp as no probs down stairs. The dampness has not helped as the room is papered(trapping moisture). this is only a problem in extreme cold weather. But I vowed to make it dry,and freshly painted before winter. Now there are a few ways to do this from what I can make out, but that all depends on who you ask. Some people say, insulated plasterboard, some say celotex then plasterboard, some say battern and board, and then theres foil backed plaster board.. . the room is small so dont want to loose 100mm on a wall. Then theres the fixing dot and dab, battern. i have had so many ideas of how to do it. I am more confussed than when I knew nothing. So think I will just go with the majority.
Will foil backed plasterboard 12.5mm (cheapest option) work, and would you dot and dab or battern? or insulated thermaline plaster board be better? would you dot and dab/battern etc? celotex?

 

[1john]

The dampness will always be there as it is condensation! ventilation is required to stop this happening. You cant dot and dab foil backed boards, they wont bond well, if at all!!

 

[carlramsay]

thanks for the response, ventilation is the key this has also been mentioned by people. I would like to put in a vent of some type but whats the best for allowing heat to stay in the room and air to circulate. Dont really want to go down the route of humidifier as cost of running and machine size in a small box room.
But having ruled out foil back, is the idea of thermaline insulated 25mm plus plasterboard to seperate the cold warm from the hot wall internal and create a barrier.Reducing condensation.like a sandwich filling. also with batterning would the foil back plaster board be away from the wall allowing air flow and not cold and hot meeting in contact.

 

[NickB_99]

thanks for the response, ventilation is the key this has also been mentioned by people. I would like to put in a vent of some type but whats the best for allowing heat to stay in the room and air to circulate. Dont really want to go down the route of humidifier as cost of running and machine size in a small box room.
But having ruled out foil back, is the idea of thermaline insulated 25mm plus plasterboard to seperate the cold warm from the hot wall internal and create a barrier.Reducing condensation.like a sandwich filling. also with batterning would the foil back plaster board be away from the wall allowing air flow and not cold and hot meeting in contact.

I agree with the guys as the ventilation solution as the way to go.
If you eliminate the condensation in this room with insulated boards of some description, it will just appear somewhere else on a different cold surface. You need to resolve the ventilation. You won't lose masses of heat.

I would think a couple of options would be (i) installing a trickle vent in the window frame (assuming uPVC double glazing or something like that)
or (ii) an air brick outside on the external wall with vent inside the room.
There may be other ways that can be suggested. e.g. any blocked up fireplace or chimney stack passing for example, that could be vented into.

 

[1john]

If you batten and insulate the wall without any ventilation then you will still have condensation on the solid wall, which will grow mould and fungus. Theoretically if you were to batten the wall in two directions and then over board with insulating plasterboard with the void left behind being ventilated to outside then this may work although Im not certain and im not sure how warm the insulated plasterboard wall would be with all the cold air behind it.

You could install a HRVU?

 

[joe-90]

Ventilation works but in winter it is no different to leaving a window open. Warm moist air is replaced by cold dry air. In other words the room will become very cold and draughty. I'd go for insulated plasterboard personally.

If it's cold enough to condense water then it's sapping heat out of your house - and you'll have to pay bigger gas bills to keep it warm.