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One percent

Loft insulation advice

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Ok hive mind of dosbods, I am wanting to insulate my loft.  there is one inch up there at present.   

The issue I have is that the loft is boarded and plaster boarded.  I can get into the eves at certain points as there are low level doors. One side is a bit tricky as there are built in cupboards.

I have asked around and no one wants to take the job on - way too time-consuming and tricky.  So, I am planning to tackle this myself xDo.O

The plan is to:

Use sheep wool as there is no way I want to work with fibreglass and this looks to be a good alternative. I don't want to use polystyrene due to the fire hazard.  It's expensive but I am saving on the labour.  

Where I can't lift the boards (the stud walls have been built off the boards so some won't lift). I am planning to try and brush something loose along between the joists with a brush. Thinking vermiculite here, but if anyone has a suggestion for an alternative...

Oh, the other problem is that I have measured the width between the joists and they are between 13 and 15 inch (330 -381mm)

Any suggestions or obvious idiot decisions spotted, gratefully received.  

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15 minutes ago, One percent said:

Ok hive mind of dosbods, I am wanting to insulate my loft.  there is one inch up there at present.   

The issue I have is that the loft is boarded and plaster boarded.  I can get into the eves at certain points as there are low level doors. One side is a bit tricky as there are built in cupboards.

I have asked around and no one wants to take the job on - way too time-consuming and tricky.  So, I am planning to tackle this myself xDo.O

The plan is to:

Use sheep wool as there is no way I want to work with fibreglass and this looks to be a good alternative. I don't want to use polystyrene due to the fire hazard.  It's expensive but I am saving on the labour.  

Where I can't lift the boards (the stud walls have been built off the boards so some won't lift). I am planning to try and brush something loose along between the joists with a brush. Thinking vermiculite here, but if anyone has a suggestion for an alternative...

Oh, the other problem is that I have measured the width between the joists and they are between 13 and 15 inch (330 -381mm)

Any suggestions or obvious idiot decisions spotted, gratefully received.  

XPS instead of EPS as it`s not flammable ,well it is but the fumes it produces extinguishes the flame the down fall is it`s expensive but on the up side IIRC 25mm of XPS is equivalent to 75 or 100mm of EPS  https://ewistore.co.uk/shop/ewi-450-polystyrene-silver-insulation-50mm/?gclid=EAIaIQobChMIq8ztwpLR3QIV1eF3Ch2s_gm3EAQYASABEgLaA_D_BwE

 

 

Secondly why do you want to insulate between the floor and the ceiling ? just concentrate on the roof making sure you leave a cavity to the felt as the timbers/roof need to breath as for the parts thats already plaster boarded there`s no easy fix for that one the easiest would be boarding over the existing stuff with insulated /laminated plaster board still a lot of work and cost  

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3 minutes ago, Long time lurking said:

XPS instead of EPS as it`s not flammable ,well it is but the fumes it produces extinguishes the flame the down fall is it`s expensive but on the up side IIRC 25mm of XPS is equivalent to 75 or 100mm of EPS  https://ewistore.co.uk/shop/ewi-450-polystyrene-silver-insulation-50mm/?gclid=EAIaIQobChMIq8ztwpLR3QIV1eF3Ch2s_gm3EAQYASABEgLaA_D_BwE

 

 

Secondly why do you want to insulate between the floor and the ceiling ? just concentrate on the roof making sure you leave a cavity to the felt as the timbers/roof need to breath as for the parts thats already plaster boarded there`s no easy fix for that one the easiest would be boarding over the existing stuff with insulated /laminated plaster board still a lot of work and cost  

Cheers.  That’s really helpful. 

I was thinking of the floor ceiling as it is a bit more accessible. I guess I can do both where I can access it. 

The room is only used as storage so it doesn’t need to be insulated.  There is no water up there so no danger of burst pipes. 

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I'm never that sure about loft insulation.  

My thoughts are along the lines of:

In a normal house with no loft insulation (or walls insulation, etc), about 25% of the energy in the house is lost to the world through the roof.

So, you put in 1" of insulation.  This is actually quite effective, at least compared with plasterboard.  So, losses go down to 10% through the roof.  Quite effective.   

So then you think, 'I saved 15% of losses through 1" of insulation.  I'm going to put more up there'.  So you put another inch down.  But you've already had the 'big win' -- that original 1" has changed thermal losses markedly.  The second inch will only get an extra 3% saved (say).  But you really want to save those last few % of losses, so you double  down to 4" of insulation.  But those extra 2" again only save an extra 2% -- the loft losses now are all about gaps here and there, thermal bridges, etc -- that are all quite difficult to get rid of.  

Oh, and in the meantime the loft temperature starts to drift down in winter, leading to condensation / damp starting to be a problem.

Edited by dgul

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No personal experience but read on line about people using sheep wool then suffering with terrible smells later, especially if it ever gets damp from condensation 

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4 minutes ago, Rowley said:

No personal experience but read on line about people using sheep wool then suffering with terrible smells later, especially if it ever gets damp from condensation 

Ah, ta, back to the drawing board then. xD a smelly house is not what I’m after. 

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5 minutes ago, Rowley said:

No personal experience but read on line about people using sheep wool then suffering with terrible smells later, especially if it ever gets damp from condensation 

It's supposed to be treated against moths and rodents. Glass wool is superior in every way apart from being a bit irritating to install. 

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9 minutes ago, whitevanman said:

It's supposed to be treated against moths and rodents. Glass wool is superior in every way apart from being a bit irritating to install. 

I’ve just priced it up and the rock wool is 77 quid while the sheep’s wool is nearer 500. o.O  I think I’ll go with the itchy one. 

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Rockwool is the way to go. It's not that bad to work with. A dust mask, some long sleeves and gloves and you'll be fine. You can get chopped stuff for pushing into gaps etc. I  think current building regs are for 270mm depth.

When I did mine I went from 50mm to 390mm. It made a massive difference both in winter and summer. Well worth it. Do the whole area and build a raised platform above the insulation for storage. Don't neglect the loft hatch. It needs to be insulated and sealed when closed or you will get condensation around the gaps as the warm air from below cools.

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12 minutes ago, stokiescum said:

did they start useing virmiculite in some places

In a house I had, the second floor bay window was built with some kind of rendered tar membrane for the outer skin and some kind of compressed cardboard sheeting for the inner. o.O  drilled holes in the top of the inner skin, sat with a funnel for about a week after work and slowly filled it with vermiculite. Worked a treat and made a terrific amount of difference. 

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So you have a proper room up there, walled, ceilinged and floored? Is there already insulation between the ceiling and the roof? Is the floor laid on proper deep floor joists or just the thin rafters of the roof? The recommended depth of insulation is much deeper than a rafter.

Rolls of insulation can be stretched or compressed a bit if your widths are a bit off compared to the breaks in the roll, failing that they can be cut to width with a saw.

Simple solution might be to lay it as normal between the eaves and the wall, bank it up to double thickness next to the wall, then just lay it over the floor in the room.

Edited by Panther

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4 minutes ago, Panther said:

So you have a proper room up there, walled, ceilinged and floored? Is there already insulation between the ceiling and the roof?

Rolls of insulation can be stretched or compressed a bit if your widths are a bit off compared to the breaks in the roll, failing that they can be cut to width with a saw.

Simple solution might be to lay it as normal between the eaves and the wall, bank it up to double thickness next to the wall, then just lay it over the floor in the room.

Well, a bodge job done 40 odd years ago.  Floor boarded, stud walls, all boarded and skimmed. Not a sniff of any insulation other than one inch stuff here and there. 

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3 hours ago, One percent said:

I’ve just priced it up and the rock wool is 77 quid while the sheep’s wool is nearer 500. o.O  I think I’ll go with the itchy one. 

Gloves. Boiler suit. Mask.

Or just make kids do it.

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3 minutes ago, One percent said:

Well, a bodge job done 40 odd years ago.  Floor boarded, stud walls, all boarded and skimmed. Not a sniff of any insulation other than one inch stuff here and there. 

Before you start lifting the floor you need to know what depth is available underneath, modern insulation is fairly deep. Measure between ceiling and floor through the hatch.

Edited by Panther

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2 minutes ago, Panther said:

Before you start lifting the floor you need to know what depth is available underneath, modern insulation is fairly deep. Measure between ceiling and floor through the hatch.

Yep done that. 4 inches. Not to current standards but better than nowt. Only thing is the boards are sheets and the stud walls have been built off them. So, I know that I’m not going to be able to get at it all 

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Flogging a dead horse, I do realize.  I've tried as a Canadian, explaining insulation  to Englishmen before and it is like talking to a wall but here goes.  First off we have way more cold to deal with than you lot so we do know a tad about insulation!!  Heat is lost by three ways ; radiation, convection and conduction.  There is not a lot you can do about radiation if you are not talking  windows so scrap that one.  Believe it or not but most heat loss in a house is by convection, especially through the roof and ceilings.  If hot air is physically escaping your house it will merrily pass through just about any kind of insulation you have so far thought up.   For insulation against conduction to be effective at all you have to eliminate convection which means some sort of physical barrier to air movement.  We use plastic sheeting but it pretty much has to be installed during construction or under a ceiling which is a messy and big job.  So the only realistic alternative when retrofitting is to use some sort of foam.  Spray the stuff in and it provides a seal against convection and is an insulator at the same time.  It comes in spray cans and is not super expensive.  It is stupid easy to use and makes a messy job an easy peasy affair.  btw it is best to not insulate under the roof itself and to provide air circulation from outside.  The best loft is a cold loft. 

Edited by Snow bird
grammar

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3 hours ago, NTB said:

Rockwool is the way to go. It's not that bad to work with. A dust mask, some long sleeves and gloves and you'll be fine. You can get chopped stuff for pushing into gaps etc. I  think current building regs are for 270mm depth.

When I did mine I went from 50mm to 390mm. It made a massive difference both in winter and summer. 

You seriously have over a foot deep insulation in your roof?

I'm surprised the building regs are so keen given windows are so ineffective at keeping the heat in.  I guess it's just a case of every little bit of difference helps.

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Read this.  Think you're going with glass wool.  If so:

Would endorse the point about wearing a paper boiler suit, gloves, and a dust mask.  Consider goggles too, cos a fibre in the eye is awful.  Make sure the paper boiler suit is your honest size, or one size too big, and good quality.  Ideally, have all the areas you're putting wool into exposed, and do the whole lot in one go, then throw the suit out.  If you try and take it off to put it back on, you'll find fibres on the inside.  Try to get the loft down to a working temperature of 15 degrees C or something - cos its horrible sweating inside those things.  Vacuum clean the area afterward.

Alternatively, polyisocyanurate board, in cases where a board product might be easier to install.  Roughly 3 times the insulation per thickness than glass wool -so 270mm glass wool = 100mm polyiso.  Celotex GA4000 and Kingspan TP10 are brand names, other brands are available.  It's not the highest spec board, but I think a good compromise between being significantly thinner than glass wool, and significantly cheaper than the higher spec products.  In the past, on a job where I could access the eaves space, I've been able to push 100mm boards up between the rafters behind the sloping plsterboard, then sealed them in position with expanding foam.
 

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4 minutes ago, Bricks & Mortar said:

Read this.  Think you're going with glass wool.  If so:

Would endorse the point about wearing a paper boiler suit, gloves, and a dust mask.  Consider goggles too, cos a fibre in the eye is awful.  Make sure the paper boiler suit is your honest size, or one size too big, and good quality.  Ideally, have all the areas you're putting wool into exposed, and do the whole lot in one go, then throw the suit out.  If you try and take it off to put it back on, you'll find fibres on the inside.  Try to get the loft down to a working temperature of 15 degrees C or something - cos its horrible sweating inside those things.  Vacuum clean the area afterward.

Alternatively, polyisocyanurate board, in cases where a board product might be easier to install.  Roughly 3 times the insulation per thickness than glass wool -so 270mm glass wool = 100mm polyiso.  Celotex GA4000 and Kingspan TP10 are brand names, other brands are available.  It's not the highest spec board, but I think a good compromise between being significantly thinner than glass wool, and significantly cheaper than the higher spec products.  In the past, on a job where I could access the eaves space, I've been able to push 100mm boards up between the rafters behind the sloping plsterboard, then sealed them in position with expanding foam.
 

Ta, that’s incredibly helpful. Is this the same as xps posted about  by long time above?  

I can access some of the rafter so in those spaces I could do the both. Would it need to be held in place while the expanding foam set?  Can I use any expanding foam of will some react with the board?  I don’t think there is much sloping plaster, it’s more a square box within the room 

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6 hours ago, One percent said:

Ok hive mind of dosbods, I am wanting to insulate my loft.  there is one inch up there at present.   

The issue I have is that the loft is boarded and plaster boarded.  I can get into the eves at certain points as there are low level doors. One side is a bit tricky as there are built in cupboards.

I have asked around and no one wants to take the job on - way too time-consuming and tricky.  So, I am planning to tackle this myself xDo.O

The plan is to:

Use sheep wool as there is no way I want to work with fibreglass and this looks to be a good alternative. I don't want to use polystyrene due to the fire hazard.  It's expensive but I am saving on the labour.  

Where I can't lift the boards (the stud walls have been built off the boards so some won't lift). I am planning to try and brush something loose along between the joists with a brush. Thinking vermiculite here, but if anyone has a suggestion for an alternative...

Oh, the other problem is that I have measured the width between the joists and they are between 13 and 15 inch (330 -381mm)

Any suggestions or obvious idiot decisions spotted, gratefully received.  

I would advise against using either sheeps wool (as discussed potentially smelly) or recycled plastic (think Grenfell). Best to do it with rockwool or recycled glass. Just wear a decent face mask while doing it. 

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38 minutes ago, Kurt Barlow said:

I would advise against using either sheeps wool (as discussed potentially smelly) or recycled plastic (think Grenfell). Best to do it with rockwool or recycled glass. Just wear a decent face mask while doing it. 

My dad was an EHO and had plenty of stories about the stuff folk got upto around the town.

His loft insulation story concerned a chap who insulated the loft of his council house with stuff he had acquired from work a bit like the song 'one bit at a time and it never cost me a dime'.

Trouble was this chap worked at the sanitary towel factory and although possessing excellent insulative properties they have amazing water retention ones as well.

Needless to say, the day came along when there was a water leak and the whole ceiling of the house collapsed on to of him while he was asleep.

When word 'leaked' out of this local calamity he got sacked as well as he had robbed 10s of 1000s of them.

Edited by Chewing Grass

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