Loft insulation

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Loft insulation
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Treacodactyl
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Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Tue Aug 25, 15 2:27 pm Post subject: Loft insulation

I need to clean out the old insulation in a loft and insulate it from scratch.

Firstly, I don't suppose anyone is aware of any deals at the moment? You used to be able to pick up loft insulation for a ï¿½1 a roll but those deals are long gone. Not being on benefits and having some insulation seems to rule me out of anything I can find.

Secondly, is there anything special I should be looking for? The cheapest options seem to be the recycled glass or plain glass mineral wool.

Prices seem to be ï¿½20 for around 5.5 SQM @ 20 cm thick.

dpack

Joined: 02 Jul 2005
Posts: 46239
Location: yes

Posted: Wed Aug 26, 15 12:03 am Post subject:

rock wool is much nicer to work with than anything glass based

be aware of wires and lights etc ,try not to make them overheat ,a gap above a fitting and lifting wires above the insulation helps.if the electrics are a bit old and manky get a spark to sort that first.

when disposing of the old stuff full ppe (including fiber proof clothes)

last one i did i used 20 cm between the joists and then 20cm across giving a deep blanket but it made it very noticeably warmer

the materials are quite cheap and pay for themselves in a year or two

make a point of dealing with any drips ,holes in the roof etc as part of the job .

dpack

Joined: 02 Jul 2005
Posts: 46239
Location: yes

Posted: Wed Aug 26, 15 12:08 am Post subject:
ps if there is any plumbing dont insulate under it ,insulate it or over it expanded polystyrene board is ideal for tanks and the foam tube stuff will do pipes.lots of folk have insulated lofts and frozen their pipes first cold snap

Treacodactyl
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Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Wed Aug 26, 15 7:13 am Post subject:
I've insulated a few lofts, so know what I'm doing. As for the material I also thought mineral wool was better than glass fibre but the stuff nowadays is called "glass mineral wool". It'll take me longer to recoup money on it, it's looking like costing ï¿½800+ and next year I should be heating with just my own wood.

sean
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Joined: 28 Oct 2004
Posts: 42219
Location: North Devon

Posted: Wed Aug 26, 15 7:20 am Post subject:
I take it you've checked eligibility for British Gas's scheme.

Treacodactyl
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Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Wed Aug 26, 15 7:25 am Post subject:
Yes, thanks, part of the house is newer and insulated so I'll not qualify. I also don't want cavity wall insulation and I'm not sure you can get one without the other.

sean
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Joined: 28 Oct 2004
Posts: 42219
Location: North Devon

Posted: Wed Aug 26, 15 7:27 am Post subject:
I thought you probably had. It seemed more open than others though so I thought it might be useful for anyone else looking at the thread. Last edited by sean on Wed Aug 26, 15 9:31 am; edited 1 time in total

Treacodactyl
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Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Wed Aug 26, 15 7:42 am Post subject:
Yes, there's more details on the MSE site: https://www.moneysavingexpert.com/utilities/free-cavity-loft-insulation

Mistress Rose

Joined: 21 Jul 2011
Posts: 15988

Posted: Thu Aug 27, 15 6:52 am Post subject:
There is a possibility that you may be able to get some grant through your county council. Ours were offering it a little while ago, and I don't think you had to be on benefits to get it.

Treacodactyl
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Thu Aug 27, 15 7:29 am Post subject:
Nothing on offer at our local council that I can get, well unless I'm willing to wait at least 9 months...

onemanband

Joined: 26 Dec 2010
Posts: 1473
Location: NCA90

Posted: Thu Aug 27, 15 5:37 pm Post subject:
I don't know of any deals, but would recommend CCF for bulk purchase.

Slim

Joined: 05 Mar 2006
Posts: 6612
Location: New England (In the US of A)

Posted: Sat Aug 29, 15 1:17 am Post subject:
air-seal first!

GrahamH

Joined: 23 May 2015
Posts: 523

Posted: Sat Aug 29, 15 4:46 am Post subject:

Do not air seal if using laid lagging. By putting insulation on to the top of the ceilings means your loft will become less warm so ensure you lag any pipework and tankage within the roof space. Some do not fit the lagging below such items to allow the rising heat to warm these items. If choosing this method, lagging is placed over the top.
Sealed will cause problems with wood rot, you need a controlled air flow, not a gale.
If you are applying insulation to the underneath of the roof covering one can then air seal the roof space; air should circulate from the rooms below.
Soffits are sometimes fitted with the vents to allow the required air flow to insulated roof spaces.

Slim

Joined: 05 Mar 2006
Posts: 6612
Location: New England (In the US of A)

Posted: Sat Aug 29, 15 11:39 am Post subject:

GrahamH wrote:

have no idea what the American equivalent of laid lagging is, but it sounds like you're talking about the difference between a hot roof and a cold roof. Seems like it's one of the most common screw-ups in DIY home improvement.

Don't rot your rafters!

Treacodactyl
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Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Sat Aug 29, 15 1:11 pm Post subject:

Slim wrote:

air-seal first!

I'm not sure what you mean but you wouldn't seal an old loft. As Graham says, leave ventilation around the edge of the loft and lay a layer of insulation between the ceiling joists, then a layer at 90ï¿½ on top of that. Put insulation on pipes, leave an uncoverd area under a tank and take care to not cover cabling to avoid overheating issues. The rafters would be ventilated from the gaps in or around the soffits..

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