On 16 Feb 2007 03:25:25 -0800, wrote:

|!i'm in the process of renovating a cafe/gallery. the building is 1
|!1/2 storeys and the upstairs is vacant at present but ultimately we
|!hope to open it up (coombed ceilings). however we are installing
|!heating downstairs and so i want to insulate the roof. i was planning
|!using rigid insulation above and beneath the rafters so i got in touch
|!with my local BC re ventilation. i was surprised to find out because
|!this is a commercial building the ventilation rules do not apply and I
|!am not obliged to install any. however I tend to think that these
|!guidelines are put in place for a reason and of course condensation
|!would be an issue so I DO WANT to ventilate but am just wondering what
|!a sensible solution would be. the rafters are at ~400mm (although
|!they do vary) centres and venting every bay seems excessive. There is
|!no soffit, I would get a vented ridge placed on the top so ventilation
|!would be required at the bottom of the roof.
|!
|!there are probably 60 bays so i was thinking perhaps venting every
|!third and providing ventilation to the ones either side by drilling
|!holes through the rafters - would this work?
|!
|!or because there is no soffit maybe removing stones (stone wall
|!exterior) from the top of of the wall.
|!
|!any recommendations greatly appreciated?

You will be covered by the Health and Safety at Work Act.
Why not contact the Health and Safety Executive?
http://www.hse.gov.uk/

As you are intending to use the premises as a cafe, you will have to
satisfy the local Environmental Health Officers eventually, why not contact
them first and gain a few brownie points.
--
Dave Fawthrop dave hyphenologist co uk
20,000 free e-books at Project Gutenberg! http://www.gutenberg.org
For Yorkshire Dialect go to www.hyphenologist.co.uk/songs/
http://www.gutenberg.org/author/John_Hartley
http://www.gutenberg.org/author/F_W_Moorman