# Thermal Bridging - Re-Insulating with Dry lining



## Pyrite-home (12 Dec 2011)

Hi 

Just wondering what advise I can get around this. We have a Thermal Bridging problem, onlty noticeable in our living room. We were told our insulation was of minimal qulaity and that we should replace it with Dry lining boards. Currently it is batons and Fibre glass.


We wonder first how much it would cost roughly for a 1,000 sq metre three bedroomed house. Secondly what type of dry lining should be applied and should the contractor rip out the existing batons and fibre glass (some say they would put the board on top of what we have which would take space out of the room). Lastly can anyone recommend someone trust worthy and good ?.

Many thanks


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## lowCO2design (12 Dec 2011)

1st of all while I don't doubt that you may have a thermal bridging problem, did the same advisor:

recommend replacing the existing dry-lining with insulated plasterboard?
if so, what is wrong with the existing? if its dampness/muold for instance,  then don't even consider fresh insulation until you get to the cause of the dampness.
were other options considered/discussed?
what is your current wall build-up?
what is the means of ventilation in your home (particularly your living room)
I would not consider a response to your query regarding type of dry-lining until you answer the above


you should also note that a calculation or a least careful consideration of all your options should be carried out before dry-lining as there are associated risks from interstitial condensation
leaving the existing insulation: (approx thermal conductivity of mineral wool at 0.044 W/mK) and then installing an EPS (approx 0.035 W/mK) or PIR (approx 0.025 W/mK) backed plasterboard, may very well increase the risk of interstitial condensation in your walls/ behind this plasterboard.
[broken link removed] is an article on thermal bridging - anyone who has told you about thermal bridging, and has then suggested dry-lining over it, had better put that in writing to you and what their professional indemnity insurance details are


[broken link removed] & here are two articles on interstitial condensation that may be relevant to your situation


I hope this at least gives you some information to question your current advisor, IMO unless he/she has considered these issues fully, you should seek another professionals opinion.



PS, I presume you mean 1000sqft house


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## Pyrite-home (13 Dec 2011)

LowC02Design thank you very much for your reply it is very informative. It is a pity you are located in Cork cause I would pay you to look at the problem. To answer some of your questions one of the BER contractors that have quoted us 13,000 for the work said he would replace existing fibre glass insulation with 102 mm board. You are right to ask what is wrong with the existing, there is not a lot wrong apart from Lines appearing where the batons are on the colder side of the house. The lines would disappear for a while if painted over. I am not sure what are wall build up is, we havent had a BER asssessment done. The ventillation in the living room consists of a small vent on the exterior wall near the fireplace. Rain water does get in through the vent from time to time. We have no mould downstairs on the walls or window sills. A small bit of mould by the window sills upstairs though especially in a room where we dry clothes. Do you know what a Vapour shield is ?, it was mentioned that there is no vapour shield in a neighbours house that has the same problem and that it could be the same situation for us. The house is generally a warm house, in fact people who stay usually complain they were too hot . We have to move out to have some pyrite repairs done and we were looking to have this fixed also. Obviously we dont want to spend big money on a job that is not necessary. Finding people trust worthy to tell us what is wrong is difficult and the more opinions I am getting the more confused I am about the problem. No other neighbours have had work done, the problem has been reported in a minority of houses but they have chosen not to do anything about it for now. Finally you are correct it is a 1000sqft house . Thanks again.


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## lowCO2design (13 Dec 2011)

well its sounds like shoddy builders all round: a pyrite problem and a lack of vapour check/barrier (vapour shield). I would not go ahead with this builder at this stage. he is correct regarding vapour shield BUT I would question whether replacing a vapour open insulation with a more closed poly based product is sensible... 

in my biased opinion getting an arch or arch tech that has retro-fitting, BER experience and a good upstanding of moisture issues to specify/ detail a solution maybe even supervise this work would be the way to go.


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