loft insulating

13 Apr 2008
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United Kingdom
i hope someone can help.
ive recently bought an old terraced house that has NO insulation except a layer of dust 2" thick.

i would like to insulate the house as it is absolutley freezing even with the heating on.

on the ceiling are the roof slates on the outside of course-No felting etc

i wish to insulate the roof area so that it can be made for boarding and storage at a later date. to begin with i just want to start the insulation process.

what should i do first?

the roof ceiling with breathable roof felting-stapled to joists? then insulating roof slabs in between the ceiling joists with a 50mm gap? to prevent dust and dirt collecting again, and to prevent cold winds coming in.
should i hoover up the orginal dust already fallen inbetween the floor joists?

then of course insulating the floor in -between the joists and then cross over the joists. so that this can be boarded over at a later date

do you know which is the best type to lay on the floor? rockwool type or this new stuff thats in a plastic covering?

any advice would be great
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Generally 250mm total thickness of insulation is the norm for roofs these days, this is the glass wool type not the solid boards. This is laid between the ceiling joists and a second layer laid perpendicular across the top to make up the total thickness. But since you want to board over the insulation at some point in the future any insulation deeper than the depth of the ceiling joists will be wasted. So put in whatever you can and accept that some insulation is better than none at all this leaves the top of the joists exposed for future boarding. You could consider insulating up the slope of the rafters too at a future date.
what size are the ceiling timbers, and how far apart?

Is the house due for reroofing?
not sure about size of joists i will be going up there soon to check

lets just say i hope it doesnt need a re-roofing. is this something i should be gettig quotes on? but how would i know?
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broken/slipped/missing/delaminated tiles, or nails nearly rusted through, or more than 10% of similar local houses have been reroofed.

there is not much point in hoovering an unfelted loft. I've done it, within a few months it was thick with filthy black dust again.
say it doesnt need a new roof, would it be best to felt it? and can this be done with buying rolls of felt and stapling it to the joist to prevent ****e coming in?
what are you intending to use this loft for?

how old is the house?

I still want to know the timber sizes.

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