Urgent help needed re- insulating internal exterior walls

blushingbride_3

Hi everyone

Well i got in trouble with building control as i didnt reaslise i needed to involve them when insulating the walls in our new office building (old house)

so far we've put 25mm celotex inbetween battens. We then planned to attach the plasterboard.

We we've been told to put more insulation to reach min u-value of 0.35

This is confusing me!

I have had a quote for Knauf thermal laminate plus but i cant work out what thickness i need.

For celotex 25mm with plasterboard attached it would be £28 a sheet

What other options would i have? all i have the in celotex brochure is the R value so how do i convert this to u value?

Please help as i need to order asap to prevent delays.

andrew-b

U-value = 1 / R-value (see http://en.wikipedia.org/wiki/R-value_%28insulation%29)

Rather than major modification to what you've already got you could maybe use insulated plasterboard rather than standard plasterboard...but run it past the building control to check before you go ahead!

MX5huggy

You need to do a uvalue calculation. Celotex will do it for you as your current wall has a uvalue which you are improving.

What is your current wall? solid brick? empty cavity with lightweight internal skin?

http://www.celotex.co.uk/Other-Resources/U-value-Calculator