# Attic insulation -- confused by options



## dub_nerd (5 Jun 2014)

Am getting an attic insulated for the first time. Very standard 1950s ex-corporation 3-bed semi, attic is approximately 400 sq.ft. Am also looking for 60-100 sq.ft of flooring for storage, an access ladder, and an electric light installed. Have had four quotes but am confused by differences in options offered, and I am pretty clueless on this stuff.

1) Fibre glass vs. rock wool vs. sheep's wool.

Sheep's wool guy says it's better insulation and less hazardous. But he seems to be offering only 4 inches, which is below minimum recommendation as far as I can tell. I think if asked to double it he'll be priced out of the job. The rock wool guy says he will blow it into the attic direct from van, whereas everyone else will lay by hand. Any downsides? Is there anything to strongly recommend any of these materials over the others?

2) Soffits.

All of them say they will have to drill holes in wooden soffits and install vents. I presume this is normal.

3) Light covers.

The rock wool guy said that existing recessed ceiling lights will have to be covered by protective covers, at about €8 x 7 lights. Two of the others said no covers required, and one said he would use €1 ceramic flower pots! The lights are low-energy LEDs.

4) Access hole.

Apparently to have an installed ladder, the access to the attic has to be widened. However there's limited room for this and may entail moving lights and ceiling smoke alarm. More worryingly, one guy says he'll have to move roof trusses (he called them "hangers" and says they are stopping central roof beam from "dishing", but are not actually supporting weight???). I'm extremely reluctant to let anyone touch these, for fear of turning a €1k insulating job into a €40k roof rebuild. He says he just has to cut it/them and make it/them more vertical. Should I just abandon the ladder/flooring idea?

5) Flooring

Some of the quotes suggested just flooring on top of joists, meaning insulation is either thin or compressed there. Others said floor would be raised using some sort of spacer. What's this all about and what's best?

Any advice much appreciated -- you can see I don't know much about anything. The quotes range from €950 to €1650.


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## Sandals (5 Jun 2014)

Female n proudly did own bungalow attic few yrs ago 154sq m...8 yr old new build with few rolls here n there where handy by busy husband. Wud have spent around 2k on whole job...

put in earthwool rolls, 3 crisscross patterns...removed whole attic floor n cleared all stuff...left a runway whole lenght of house, covered over and marked..ideally flooring should be raised avoiding compression...shops all said 3 overload but never wanted to go back again...used spaceblankets over living area, which I feel worth it...

used drainage pipes over our 14 downlighters, sealed them n wrapped top n bottom with special bought insulating tape and completely wrapped in insulation, hav a spray paint where they r in case...hav bits of cellotape on all switchs in kitchen n hall so cant turn on the downlighters anymore....some told me that the claypots too heavy depending on their location on the ceiling and support and the chance they could mark they ceiling as they absorb moisture as clay....

Left the breathable space at the edges....had hatch fitted already between truss roof but himself built a box hinged to complely cover the stairs n I wrapped it with insulation for extra draftproofing.

immediate effect in house holding heat....cant discuss saving money etc as we only burn turf but previous years we always ran out of turf due to shed size and following we didnt but we did fit a stove the following year so could account for it also....this was the start of whole pile of helping house hold heat or prevent draughts....the quickest n cheapest being an insulating door curtains on our front door and two side glass panels...


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## Guns N Roses (6 Jun 2014)

dub_nerd said:


> 1) Fibre glass vs. rock wool vs. sheep's wool.
> 
> Sheep's wool guy says it's better insulation and less hazardous. But he seems to be offering only 4 inches, which is below minimum recommendation as far as I can tell. I think if asked to double it he'll be priced out of the job. The rock wool guy says he will blow it into the attic direct from van, whereas everyone else will lay by hand. Any downsides? Is there anything to strongly recommend any of these materials over the others?


All of these material should have similar thermal conductivity properties. The only different will be price and environmental concerns. Sheepswool is environmental friendly while the other two are not. Personally I would go for the sheeps wool but if price is a factor then I would choose the fibre quilt. You should install at least 2 layers (each 100mm or 4 inches thick) of quilt running alternative directions. I'm not a big fan of blow in insulation in attic spaces.



dub_nerd said:


> 2) Soffits.
> All of them say they will have to drill holes in wooden soffits and install vents. I presume this is normal.


 
Yes. This is okay. All modern buildings are required to have cross ventilation in attic spaces to prevent condensation.



dub_nerd said:


> 3) Light covers.
> 
> The rock wool guy said that existing recessed ceiling lights will have to be covered by protective covers, at about €8 x 7 lights. Two of the others said no covers required, and one said he would use €1 ceramic flower pots! The lights are low-energy LEDs.


 
Yes. You should provide covers for the recessed ceiling lights. If you're paying to have the job done right then use an approved cover rather than a makeship alternative such as flower pots.




dub_nerd said:


> said no covers required, and one said he would use €1 ceramic flower pots! The lights are low-energy LEDs.
> 
> 4) Access hole.
> 
> Apparently to have an installed ladder, the access to the attic has to be widened. However there's limited room for this and may entail moving lights and ceiling smoke alarm. More worryingly, one guy says he'll have to move roof trusses (he called them "hangers" and says they are stopping central roof beam from "dishing", but are not actually supporting weight???). I'm extremely reluctant to let anyone touch these, for fear of turning a €1k insulating job into a €40k roof rebuild. He says he just has to cut it/them and make it/them more vertical. Should I just abandon the ladder/flooring idea?


 
Considering the age of your house, I would expect that you would have to widen the access to the attic space. However I wouldn't allow any contractor alter the construction of the attic without proper certification from a reputable structural engineer.



dub_nerd said:


> 5) Flooring
> Some of the quotes suggested just flooring on top of joists, meaning insulation is either thin or compressed there. Others said floor would be raised using some sort of spacer. What's this all about and what's best?


If you intend to use quilt insulation then you will need to raise the flooring to accommodate enough insulation. This can be done by screwing spacer battens onto the existing ceiling joists and then screwing your flooring on top. Compressing the insulation will reduce its effectiveness. If you don't want to raise the flooring then you need to consider a different material with a lower thermal conductivity such rigid board insulation that can be fitted between the ceiling joists.


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## dub_nerd (8 Jun 2014)

Thanks for the very helpful replies. I believe one or more of the quotes are also proposing to cut through joists to widen the attic access hole. Is that also a bad idea? Basically, should we get the insulation done and abandon any thoughts of making the attic more accessible for storage?


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## car (10 Jun 2014)

dub_nerd said:


> Thanks for the very helpful replies. I believe one or more of the quotes are also proposing to cut through joists to widen the attic access hole. Is that also a bad idea? Basically, should we get the insulation done and abandon any thoughts of making the attic more accessible for storage?



I went through all this last year. 

The spot light covers are Heat displacement.  I used ceramic pots from ikea @1e each.  with sealant underneath.   I had something like 22 spots lights upstairs, at 8e a pop, I think I worked out 10 years+ payback on the return on the energy lost through those alone.

The ratings on each of the insulation types differ, earthwool is a min 300mm recommended but far cheaper than the sheepswool which doesnt need 300mm.  

You can use the attic for storage however youll need to put down insulated walkboards to your storage area which should not be on any of the insulation.   I made a load of shelves across the joists for this using some old bed slats.   

I got a sheet of insulated polysio second hand on adverts and made a hat to go over the attic door when I have it closed.   found a tutorial on youtube but you can figure it out. Just need some gaff tape and some sealant once you cut your measurements.


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## dub_nerd (11 Jun 2014)

Thanks car.

Any thoughts on cutting through joists? I thought joists were only supported at the edges, so how can anyone propose to cut through one?


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