Hi all,
Still at the planning stage of a possible loft conversion in the near future. I will be doing the bulk of the work myself over time so it wont be a quick job. I'm not an experienced DIY'er but i'm not a novice either. I have a small question to do with u values and hopefully some of the more knowledgeable people within this forum can keep me on the straight and narrow.
Background.
Loft roof beams are 100mm (4") deep to sarking battons and tiles. I have to have a 50mm air gap, so my availible depth of insulation is 50mm. A Kingspan derivitive called Xtratherm will give me a u value of around 0.25 with 50 mm inbetween the rafters and 30mm below and across. This will obviously infringe slightly on the availible space. There are other products but i dont know much about them. One idea is 50mm Xtratherm between the rafters and a Screwfix product called 'super quilt' http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=101893&ts=97478&id=25009 with a u value of 0.2 across then 12.7mm duplex plasterboard.
Question.
Never having used this product or know anyone that does will that give the proper u value or close to it.
2nd question.
Is the U value calculeted from an average of the whole room? not just U values of individual walls all being under the stated limits (for my county 0.2 U. The reason for this is i can extra insulate the eaves and loose some on the slopes where i need the space.
I thank you all for any and all advice given.. its much appreciated
Dinger
Still at the planning stage of a possible loft conversion in the near future. I will be doing the bulk of the work myself over time so it wont be a quick job. I'm not an experienced DIY'er but i'm not a novice either. I have a small question to do with u values and hopefully some of the more knowledgeable people within this forum can keep me on the straight and narrow.
Background.
Loft roof beams are 100mm (4") deep to sarking battons and tiles. I have to have a 50mm air gap, so my availible depth of insulation is 50mm. A Kingspan derivitive called Xtratherm will give me a u value of around 0.25 with 50 mm inbetween the rafters and 30mm below and across. This will obviously infringe slightly on the availible space. There are other products but i dont know much about them. One idea is 50mm Xtratherm between the rafters and a Screwfix product called 'super quilt' http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=101893&ts=97478&id=25009 with a u value of 0.2 across then 12.7mm duplex plasterboard.
Question.
Never having used this product or know anyone that does will that give the proper u value or close to it.
2nd question.
Is the U value calculeted from an average of the whole room? not just U values of individual walls all being under the stated limits (for my county 0.2 U. The reason for this is i can extra insulate the eaves and loose some on the slopes where i need the space.
I thank you all for any and all advice given.. its much appreciated
Dinger