ventilation and insulation

[rob200375]

hi,

i have a question about ventilation and insulation on a loft conversion.
I have attached a pic of how my tiles are fixed currently, i have no felt under my tiles, and i have been told i need to have a 10mm ventilation gap between tiles and insulation ( celotex will be used).
would the beams that hold the tiles on be sufficient or do i have to attach a vertical beam to the current horizontal beams to the underside of the tiles to allow sufficient ventilation.

I may have confused people as i do tend to waffle so i await your suggestions.

View media item 1378

 

[Deluks]

They are called battens, thin strips of timber that the tiles are fixed to.

Not quite sure I understand the question but in any case, 10mm isn't enough, you'll need more like 50mm.

Can I ask why are you doing this, and will you be boarding up inside the loft afterwards?

 

[rob200375]

i was told you only need a 10mm ventilation gap and a minimum of 50mm insulation?

what i was trying to explain is that would the battens that go horizontally be sufficient for the ventilation gap or would i need to add more thin battens vertically to give a free flow of air from top to bottom.

hope this makes more sense.

 

[Deluks]

i was told you only need a 10mm ventilation gap and a minimum of 50mm insulation?

It depends totally on what you are trying to achieve from all this.

Is the loft boarded? Is the loft floor insulated? Will you be spending time in the loft or just storing christmas decs?

 

[rob200375]

going through building regs, and converting it into a full habitatal room with fixed stairs.

Would what i suggested be sufficient for building regs certificate

 

[Deluks]

Nah, building regs will require about 120mm of insulation, between and over the underside of the joists. They might insist on refelting the roof as well, which tbh is a very good idea. You won't want water getting in under the tiles, discreetly rotting the timbers or ruining your newly plastered ceilings.

You're gonna need a bigger boat!*




*budget

 

[rob200375]

thanks for the advice I will go and check with build regs and go with what they say

thanks for the input

 

[rob200375]

View media item 4171this is how the tiles currently look,

would superfoil sf19 or sf40 attached to rafters and then batten off with plasterboard on be sufficient for building regs?

i would do it as per the right hand picture on the link below

http://www.superfoil.co.uk/SF19-FAQ-datasheet.html

the only difference is I dont have the breather membrane as shown.

 

[Deluks]

would superfoil sf19 or sf40 attached to rafters and then batten off with plasterboard on be sufficient for building regs?

Only your building control officer can answer that one, as some local authorities will accept the foil and some won't, afaik.

How do you feel about removing all your tiles, stapling membrane to your rafters and putting all the tiles back again? Membrane is a must in any loft conversion IMO. Once you have boarded up the inside you'll have no early warning of any leaks, so the belt n braces that felting gives is essential.