Afternoon, Is it OK to lay earthwool and the 18mm board right up to the wall and eves? Incidentally i haven't spotted any vents up here but its dry as a bone. Thanks Fats
Hi Sean, Thanks for posting. No, i don't believe so. I cannot see any within the loft area and there aren't any visible on the outside either (please see attachment) - other than the hole i've drilled for the satellite cable that is! Thanks, Fats
you have to be very careful that you don't create yourself a nice soggy loft - when your house was built external doors and windows leaked air, as did the floorboards and ceiling - so there tended to always be a good flow of air through to help extract any vapor - these days, with air tight doors and windows, and foil backed PB, and the need to stop that expensive heat leaking it's easy to get next to no droughts and flow - which will eventually cause issues there's no issue running the wool fully to the eaves, but you will have to have some means of enabling a flow, usually done by extending the eaves vents upwards above the top of your cozy earthwool and some ridge vents if you've used foil backed PB, with fully taped joints, on all ceilings below that would stop much of the vapor rising
Point taken, thanks. I've also noticed some of the vents in the bedrooms have been boarded over (exterior still vented) We didn't use foil backed board - just 12.5mm regular gyproc and scrimmed all round. So would something like these be OK, and if so how would extend the air flow - use some kind of ducting? http://www.screwfix.com/p/circular-soffit-vent-white-70mm-pack-of-10/68936 Thanks for all your help to date Fats
yep they'd do, either leave the wool short of them, or pierce the wool with a length of downpipe offcut (one end cut at an angle), anything will do as long as the flow up into the loft space isn't impaired this illustrates what you need to achieve, I suspect these are of US origin as they do roof void ventilation far better than it's done here
Excellent thanks Sean, will do. One last question: is there a rule of thumb on how many of these should be fitted? I trust both sides so the flow is there. Thanks again. Fats
these pictures below shows the effect you are wanting to achieve - no rule of thumb really, you can get away with just venting the eaves towards the prevailing wind if the wind is particularly directional - every third bay should do the bottom image shows ridge venting but mid roof vents are more commonly used - such as these http://www.screwfix.com/p/glidevale-versa-tile-vent-grey-110mm/86667
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