Kingspan Rafter Insulation

[Jacob98]

Hi,

I'm currently fitting Kingspan K7 Insulation, between the rafters, leaving a minimum 50mm air gap above.

I'm hoping to fill any gaps left with expanding foam and fit K18 plasterboard.

I'm insulating part of the roof, at the moment, in the room we're working on, and hoping to do the rest at a later date.

Should I leave any gap at the bottom or completely insulate as much as I can.

Does anyone see any problems, with what I am doing?

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• Jacob98
• 10 Mar 2013
• 1

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• Jacob98
• 10 Mar 2013
• 1

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• Jacob98
• 10 Mar 2013
• 1

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• Jacob98
• 10 Mar 2013
• 1

 

[Alastairreid]

No problem what you are doing but you need to vent eaves and ridge for thru ventilation.

 

[Jacob98]

No problem what you are doing but you need to vent eaves and ridge for thru ventilation.

Thanks for the reply, what's the best way of venting the eaves?

This is the main area that I am not entirely sure about.

The property is a century old mid terrace.

 

[Alastairreid]

Either over fascia, or soffit vents ideally or tile vents as a last option.

http://www.manthorpe.co.uk/Building/Products/Roof-Ventilation/Over-Fascia-Vent.html


http://www.hambleside-danelaw.co.uk...ffit-ventilators/soffit-ventilator-hd8000.php

 

[freddiemercurystwin]

Err unless you fit ridge vents at the top or a tile vent between each rafter at the top you are asking for trouble, or how is that moist air in the 50mm air gap gonna escape?

 

[Alastairreid]

Assumed the ridge ventilation was in place.

 

[datarebal]

your high level venting will be an issue as your roof has no breathable 1f felt. you could open the felt laps but a bit of risk... ridge venting required.

 

[Jacob98]

Looks like its a lot more complicated then I initially thought.

I need ridge vents and eaves ventilation installing across the roof. I think I'll need to find a decent roofer for this.

The attached diagram is the layout of the roof, the red bit is the area that I want to insulate now, above the yellow bit is a small loft and the green bit is what I want to insulate at a later date. The brown is a wall that splits the two rooms.

If I insulate the red area, would I still need to put ventilation in place or can I wait until, I've insulated the rest of the roof.

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• Jacob98
• 10 Mar 2013
• 1

 

[datarebal]

as you have a roof void at high level vent tiles will do..