Attic insulation and flooring - need helpful advice please!!

Linto

Hi,
We were hoping for 400mm of rockwool insulation in our attic but with joist of only 100mm I'm not sure what to do. Do we use loft legs or some such thing, or split it and insulate the upper side along the rafters? Or do we use board?
Or maybe its best to use the foam?
Anyone know what rate per sq mt we should pay for this insulation and flooring. (Attic are is approx 55mt sq)

engineermike

Linto wrote: »

Hi,
We were hoping for 400mm of rockwool insulation in our attic but with joist of only 100mm I'm not sure what to do. Do we use loft legs or some such thing, or split it and insulate the upper side along the rafters? Or do we use board?
Or maybe its best to use the foam?
Anyone know what rate per sq mt we should pay for this insulation and flooring. (Attic are is approx 55mt sq)

hi,
Are you trying to deck out the entire attic space after insulation for storage ?
As opposed to a decked walkway to access the cold store / header tank etc.
m f

Linto

engineermike wrote: »

hi,
Are you trying to deck out the entire attic space after insulation for storage ?
As opposed to a decked walkway to access the cold store / header tank etc.
m f

Yes, we're trying to floor entire attic for storage.

engineermike

Hi,
General rule of thumb is that fibre insulation will lose R-value when under compression. It removes air pockets.
Best advice is consult with the insulation manufacture firstly for there direction (as there are many types on the market).
At 400mm depth of batt/ fibre insulation material your well over the SEAI recommended 300mm. So if a raised floor is appropriate and gauged correctly you shouldn't be diminishing the insulation value adversely.
Just remember to floor as required, but don't deck right up into the eaves, allow for cross ventilation of your roof, and don't stuff the insulation over the soffit vents or other roof vents.
Also don't cover down lights / recessed spot light luminaries with insulation. Allow for 75mm gap surrounding the light fitting & don't enclose the transformer with insulation either. At best you will have bulbs blowing more frequently & at worst a risk of fire.
400 mm ( or even 300mm) of fiber will pretty much blanket the attic and hide all ceiling timbers / services etc.\
mike f:)

Barnicled

Did you ever get a rough cost per sqft on this Linto??

Linto

Barnicled wrote: »

Did you ever get a rough cost per sqft on this Linto??

20per m2 for supply and fit for the flooring.

Barnicled

Thanks Linto...And then presumably the insulation is additional to this 20 yoyos?

Linto

Barnicled wrote: »

Thanks Linto...And then presumably the insulation is additional to this 20 yoyos?

Yes