300mm attic joists

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zanub

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My parents plan on finishing insulating their attic. As was typical of 1970's bungalow the insulation is woeful! 1/2 the attic is insulated & for now they just want to finish it off.

Problem is the joists are just over 300mm wide and most DIY store sell minimum 400mm rolls. Has anyone any advise on what they're options are - money is an issue, they've just had to putting in a new central heating sys, rad's etc so they're not flush and plan on doing it themselves.
 
Can't see anything wrong with putting 400 loft roll between 300 joist, just lay in but dont flatten down
 
Hi

I think you can get loose stuff that's blown in. This would get around the problem of the non-standard width. Failing that you could try cutting the standard rolls. Cut it when it's still rolled up - I think a handsaw is what's usually used.
 
just done attic with rolls, used a bread knife, excellent, as above cut with plastic on,
 
I've read on several sites to cut it, so most likely that's what we'll do. I might buy a roll this week end and see how it goes. It's not going to be a straight forward job to lay the insulation as the attic is a criss crossed with electrical cable & the new qualpex pipes just installed..... plus boxes and boxes of junk that should have been dumped...
 
but well worth it, our house is a completely different house, holds heat so much its unbelievable, had free HALO ESB survey carried out and they said instant work needed on attic as patchy and non-existent insulation. Well worth the money and time and effort....B&Q have a pay for three get one free on all insulation, we used 200mm rolls and bought the space blankets for over the sitting room as pricey.
 
I called into local B&Q today. A very helpful assistant gave me plenty of advise. He suggested the 1200mm roll and to cut it to size. it's about €43 a roll and covers up to 8sq m. Its 170mm dept. He said they have a new delivery on Tuesday of insulation which is cheaper, about thirty odd euro but he didn't know what sq meterage it covered.

I'm to ring him Tuesday and he'll tell me the cost and sq mtr coverage of new consignment, so we'll probably run with one or the other depending of which gives the best value and there is the 3 for 2 offer.
 
No wonder he was nice if he was selling for €43 a roll, Ye should be getting nerarly 3 rolls for that
 
seantheman - can you suggest somewhere where I can buy the rolls cheaper and cover more sq metres ???
 
I know they're only about €17 for 150mm roll (8mtr sq)in Donegal. I'm sure Woodies or Heitons would be cheaper than €43
 
Priced insulation from local builders merchants. ?19 a roll. It's 1200mm wide & covers 7sq mtr. It's 150mm thick compared to b&q space blanket 170mm. What's difference between "combi" roll and space blanket ?
 
B&Q athlone/galway €24.95 per roll, 3 for 2, 200mm, the 170mm is cheaper at €21.95 again 3 for 2. When we started first we bought 10 roles in ganleys athlone for €300 so then heard B&Q doing deal.

The combi roll is the fibreglass stuff you roll out, bit itchy etc but ok if you cover up well.

The space blanket is the stuff inside a plastic/tinfoil cover so you dont actually touch the fibreglass. You place the tinfoil up towards the attic/roof. Was told it was better so just purchased it for the sitting room. I bought the really small rolls so extremely handy to carry/roll out etc.

I would double check everything in B&Q as different people tell you diff things, we drove to athlone one morning for few more rolls, out of stock, asked girl to ring galway to see if any, anyway told they were being discontinued and no point in her ringing, so husband rang galway from van and lady said 500 in stock, drove to galway, only 9 left of the 500 that originally came in, lucky our van crew cab so can only carry nine anyway.
 
I priced the 1200mm space blanket from homebase. It's ?19.99 a roll. No 3 for 2 offer thought. We're doing d job ourselves & I gather the space blanket is easier to cut while still wrapped and then lay. Homebase & b&q are literally beside each other in waterford. You'd think they would be similar pricing. Just goes to show
 
Shame to cut space blanket as your paying extra for it and its benefits. I would imagine its harder to cut than combi roll as your cutting through a good few layers of plastic/fibre/tinfoil and how would you keep all three layers together when rolling. It would be like trying to cut a regular plastic bag into strips....

Also I found it easier to let the rolls unroll themselves (as they always wanted to do once free from plastic outside) and then place into position with my breadknife.

Also the combi-roll have markers on the plastic at 400 and the rolls are already pre-cut inside so easy enough to slice through. Its terrible hard to cut off say a strip of the insulation when I only needed a small bit.
 
The attic is not clear & is full of electrical wires and newly installed qualpex so its not a case of letting it roll out more like it'll have to be tucked under wire & pipe. I didn't know by cutting space blanket it diminishes the benefits - do new builds have 1200mm wide joists? Does cutting combi roll not affect benefits? Im confused now. You would think something like insulation would be straightforward! I think I will buy a roll of each on a trial run and see which is better/easier to lay.
 
Does anyone recomend the blown in loose insulation, how does it compare to the more traditional rolls of loft insulation?
 
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