Ventilation- Insullation question.

[gms]

I have just replaced a felted flat roof with a 12.5 degree (lean too type) pitched tiled roof with much help and advice from this forum. The roof is somewhat un-orthadox in that the rafters run from left to right rather than top to bottom. I had planned to use standard vent tiles at the top and ventilated soffit at the bottom, however thinking about it, now, when the plaster board and insullation is added only the top two rafters and the bottom one at the soffit will be ventilated.
The total area of the roof is 32sq m. 8x4m. The first 5x4 abut the main house wall to a load baring wall and is a kitchen. I intend to retain the high sloping ceiling. The remaining area is a utility room with a normal hight ceiling with a small loft space above.. A workaround could be to insert air bricks at the top of the outer wall of the utility room and then more at the top of the inner load baring wall. However I am struglling to come up with a sollution for the other end where it abutts the main house.
Is there a way of venting it under or adjacent to the flashing. Is there a product out there made for such a situtation?

Photos of the roof looking internally at both ends
http://i138.photobucket.com/albums/q266/gms_photo/DSC03878.jpg
http://i138.photobucket.com/albums/q266/gms_photo/DSC03879.jpg

Thanks in advance for any advice.


gms

 

[breezer]

guess what

does

use it and look in forum info

 

[Roofer]

That's really helpful Breezer.

gms look here at pages 27 and 28 for some ideas. Similar products from other manufacturers are available

 

[breezer]

That's really helpful Breezer.

gms thought so too, look

"Last edited by gms on Wed Dec 06, 2006 20:22, edited 2 times in total"

 

[gms]

Hi Breezer and Roofer,
Yes I was initially thrown a bit by your reply Breezer 'it sounded a little terse.
However when I re read my post I relalised it was incomplete. So no offense taken,....... but I'm pleased Roofer felt similarly to me on his first reading of your reply.

Roofer, your link is great and just what I needed. Thanks. Also taking Breezer's advice I 'Googled'around last evening and found http://www.cavitytrays.co.uk/ their RAV - FL tray also might do the job,however they only do 12m lengths and until I phone today I wont know the cost. They also make ventilated lead type flashing too in 5m lengths which might do the job. As the wall the roof abuts a north facing and sheltered by a parapet party wall it gets relief from really driving rain and winds.

Going off subject a tad but useful to say
A point for all to keep in mind when posting and getting irritated by the tone of some replies is this. With this form of communictaion it is so easy and often hastily to fire off stuff without having given enough thought or leeway to the recipient. I am 60 young, have always been bowled over by the enormouse levels of generosity that the internet gives rise to. These forums and others like it are the first places I now look for sound advice on any complex subjects both pratical and philosophical.

Thanks for responding please don't get disheartened if we don't get it right straight away, and remember:
'as I am (and all the silver surfer members) so you will be'... ............I think the next line is........ 'so prepare for death and follow me' ''


Continue being kind to each other ......even when we say something stupid!

Thanks again

gms

PS at least I'm in the dry now .... the felt and battens are ON! and its not stopped raining in drought ridden Kent.

 

[masona]

Is there a way of venting it under or adjacent to the flashing. Is there a product out there made for such a situtation?

Normally when we get a situation where the joists run the other way is to put 3"x1" approximatey 400mm centre on top of the joists in opposite direction then board it over, this will give you a cross flow of air circulation, as the roof is already on, let me have a think about this one how to get round it.

 

[masona]

I had planned to use standard vent tiles at the top and ventilated soffit at the bottom, however thinking about it, now, when the plaster board and insullation is added only the top two rafters and the bottom one at the soffit will be ventilated.

Just has a thought, didn't take long did it

What if you use 3"x1" in opposite direction of the joists underneath before fitting the plasterboards (make sure the plasterboard joint on the centre of the 3"x1") then use tile roof vents above on the centre between the joists and when fitting insulation between the joists, use insulation slab type and leave a gap of approximately 50mm or cut out round hole. The air should come in via the soffit vent and straight to all the tile roof vents.

Another idea is to drill a number of holes at the top of the joists, will be a bit awkward though