Insulating/Ventilating Shed Roof

[Bigbob]

Hi peeps,
My first post here so here goes.
Im currently insulating my recently purchased shed,for general woodwork and the like.Shed is 12x8,3/4" t & g with a mineral felt roof on top of OSB.

Now I've spoken to a couple of people about this and some are telling me to insulate the roof and leave an air gap others are telling me because my shed roof has no ventilation(fascia/soffit vents) there is no point in leaving an air gap as all I'll do is create a vacumn of hot air.(suppose if there is no gap ,theres no room for a build up of hot air)

I've also been told to put insulation in and leave NO gap but just put an air inlet low on oneside of my walls and another outlet high on an opposite wall to create air flow(sounds reasonable enough)

I do plan on using a heater in the winter and would prefer it not to be like a sauna in the summer so which method would you guys think would be the best.

 

[exigetastic]

Personally I looked at it this way, my shed and everything in it is for experimenting. Therefore I took the view that whilst I didn't do what would be percieved wisdom* for a house (Ignoring the fact that a house will be much more humid than a shed, unless I fit a shower, kettle etc. etc.) the cost of replacing some OSB for the roof would be pretty minimal in 5 or 10 years time.

I suspect that the weakest link will be the mineral felt rather than condensation build up that will lead to failure. (IIRC my felt was warranted for 5 years)

Maybe someone will post up on here a horror story about how they wish they had put an airgap in the roof when it started leaking after a year, but I suspect many of us are guilty of over engineering our Workshops!

Si


* this seems to get more and more onerous over time!

 

[J D Architectural Joinery]

this may help you.

http://www.insulateonline.com/index1.ht ... 2.htm~main

 

[antihero]

Hi Bigbob,
I'm also insulating my shed and also have been wondering wot to do with the roof by way of insulating/air gaps.
Same boat as yerself,no vents in the roof space,fascia.
My thinking was to just drill some holes either side of the fascia and leave an air gap but I may just insulate without a gap and insert an air inlet/outlet on the walls and hope for the best!
Suppose thats the trade off when you buy a shed instead of building one,you can plan for these things.
Let me know if you think of a better way.