Key Post: Attic Insulation.

Re: Sheeps wool insulation, how much and what about existing glass fibre?

Ask yourself why you want extra sheeps wool insulation. The mineral fibres of the gass wool wont go away by laying sheeps wool on/under it.
If you want cheap insulation then go for glass wool. If you want half ways cheap insulation go for wrapped and packed glass wool. But if you want healthy insulation then change the house. Once loose mineral fibre has polluted a place it's very hard to get rid of it.
200mm glass/rock/sheeps wool is the legal minimum of roof insulation.
I used two 100mm layers of sheeps wool.
The recessed lights would have to be covered at their backside. This could be done by clay flowerpots for example. Clay because most likely the cable's insulation used at the lights are made from PVC which should not come into contact with PS (polystyrene). And plastic flower pots are made quiet often from the cheaper PS material. An alternative is changing the PVC cables to silicone cables. Or cover the existing ones in ducting.
 
Re: Sheeps wool insulation, how much and what about existing glass fibre?

Thanks heinbloed. I will think about what we should do. I was thinking healthy but I also don't want to generate any unnecessary waste. I'm not too concerned about the cost. We won't be moving house though. Good idea with the flowerpots.
I regularly read your posts by the way. Having lived for 8 years in Germany and Austria, I am pretty horrified by the standard and finish of many Irish houses.
 
Just a quick note about the attic insulation - it may be pulled back away from ceiling lights that are installed through the plasterboard into the ceiling. They can become extremely hot and so they can be a fire hazard
 
If a ceiling light emits to much heat then it shouldn't be installed in the first place. All electrical equipment should state the purpose for which it is designed. Igniting a standard insulation material would be out of the scope. Talk to your electrician, he would know what/whos insurance is responsible for such a quality problem.
 
Hi,
Joists in my attic is only 100mm high and I would like to put chip board after the insulation work. Will 100mm thick insulation be enough or do I have to add additional joists for a 200mm insulation thickness?

I don't know how to go about it. I don't want an extra bedroom in the attic but some storage space.

Any suggestions welcome!

Thanks
 
Heinbloed - do you have opinion on the merits of shredded paper (blown in) v sheepswool? Ecowise in Galway say you get the same level of insulation, but the paper is half the price.
 

If the joists are only 100mm then i would be worrying about bigger issues that the insulation. What is your reason for putting down the chipboard?
 
Razza, Heinbloed has been banned since that post, so will be unable to respond. Ask Ecowise for the U value of their product and ask what kind of guarantee they offer.

Littletom, the more insulation you can put in there the better. 150mm would be the recommended minimum.
 
If the joists are only 100mm then i would be worrying about bigger issues that the insulation. What is your reason for putting down the chipboard?

Hi Ludermor,

Thanks for the response. So do u think I should increase the height of the joists? I thought putting down chipboard will make it easier to walk on attic.
 

Thanks Leo. I would like to put 200mm, but the joists being only 100mm height, I won't be able to put down chip board for easy walking on the attic and storing things there.
 
Agreed, you should raise the height. Not 100% sure about how best to go about that. Obviously if you just add extra height to a section, then floor that to use for storage, you're putting weight on the joists that they weren't designed to carry. It depends on the layout and whether the load can be easily transferred to walls, etc.
 
I insulated my attic but i put the fibre glass between roof rafters, then
covered it with plasterboard, floored the attic and have some degree of heat in that big void up there,and can also be used for storage /playroom etc
 
have some degree of heat in that big void up there,and can also be used for storage /playroom etc

Have you been up there in winter? It'll be freezing (at least it should be if your floor insulation is doing its job!)
 
I insulated my attic but i put the fibre glass between roof rafters, then
covered it with plasterboard, floored the attic and have some degree of heat in that big void up there,and can also be used for storage /playroom etc

You should install a light as well as its a dangerous 'ol spot especially with all them spiders lurking ..........
 
Hello, I have a query in relation to retro-insulating a converted attic of a bungalow.
The attic of our bungalow was converted into a room during the 80s however during the conversion, no insulation was placed underneath the floor board. Similarly the roof in the converted attic space was neither insulated adequately. This converted attic is not being used anymore and would only be used for storage if ever used again.
Again, this is probably a silly question, but is it worth while to lift up the floorboards and fill the gaps with insulation, or is the floorboard adequate and carpet enough insulation for the below living space? Or is there any other insulating solution instead of lifting up the floor boards as this would be considerable work. Again the house is not a warm house, so I do think the attic does require some form of insulation. The whole attic is not converted and the part the is not ''converted'' is insulated.
 
Hi all,

Need to add additional insulation into my attic. Basically at the moment it has 60mm of Xtherm in between the joists. The joists are 100mm deep. So is it OK to lay a blanket in the opposite direction with this gap between the layers? Also noticed that B&Q are doing a sale on loft insulation at the moment and don't want to miss it again (like last year!!) if its good value. For example they are selling a Knauf Earth Blanket top up insulation (200mmx370mmx4m) for €13. Is that good value? The attic area is approx 10mx10m so would need about 65 blankets at a total cost of €845. Does that appear dear?

Also in places the Xtherm isn't a snug fit between the joists, can I plug these areas with say rockwool as it would seem easier to cut to shape etc?

Thanks

S.
 
Have a similar problem to Suzies.Joists are only 100mm deep.So what I wanted to know is would it be ok to use 100mm deep glass wool in between the joists and 200mm opposite direction to give me 300mm in total?
Or could I go 200mm in between the joists and 200mm accross or would I be compressing the lower layer too much?
Thanks,
Richie
 
Does anyone know how Kingspan insulation compares to Glass wool insulation ? Am I correct in thinking they used in different situations ?
ie Glass wool over the upstairs ceiling joists and Kingspan in the roof joists ?
 

Anyone??