Rate my attic! [pics]

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fullerand

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Hi,

I live in a 70s-built semi-D, the attic of which is insulated by what seems to be loose fibreglass-type material (see below). The depth varies considerably around the attic from 7" down to maybe 1" (where it's compressed).

Does this sound like your own attic, and if not is it something you'd be inclined to rectify ASAP? From the pics am I correct to assume it's fibreglass?

I'm hoping to get a price for replacing it this year (I presume it's a job for summer), if anyone had pricing pointers, that'd help.

Thanks


attic2_small.jpg


attic1_small.jpg
 
Looks like blown-in glass fibre or mineral wool, although could be cellulose either. You should really increase the overall insulation depth by another 6" at least (current Irish building regulations would require new builds to have 10 or 12" of glass fibre quilt in the loft space). You could do this yourself by draping 6" quilt across the ceiling joists (being careful to provide for access etc) and ensuring that roof ventilation at the eaves is not obstructed. I would definitely recommend doing this in the winter- when the roof space is cold; this is an awful job at the best of times but especially so in a hot attic.
 
Carpenter, I have this stuff in my attic. I also have recessed lighting on the landing. Do I need to keep a space clear around the lights where they protrude into the attic and if I put roll out fibre glass on top will that cause a problem?
Thanks.
 
From the pictures it looks like eaves ventilation is a problem. There are special vents that you can fit that keep the insulation back the correct amount to allow air to circulate.

Regarding the recessed lights one of the best solutions I have seen is to use flower pots upside down (ceramic/red pots) and cover the fitting in the attic. You can then insulate away to your hearts content. PS I don't know how that goes down with RECI and such but they do have directives for electricians on how to install recessed lights.
 
Carpenter said:
You could do this yourself by draping 6" quilt across the ceiling joists (being careful to provide for access etc) and ensuring that roof ventilation at the eaves is not obstructed.
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You'll also need to make sure that wiring (such as that in the pictures) is routed across the top of any new insulation. Don't cover electrics in insulation as it's a fire hazard.
 
Insulation should be kept away from electrical cables (unless they are rated otherwise) and recessed light fittings. There are a number of ways to keep light fittings clear of insulation- you can fabricate small open ended boxes from MDF, ply or plasterboard, which will keep a clear space around the light fittings and allow heat to diffuse. Another solution is to use small offcuts of 6" (160mm) diameter pvc sewer pipe for the same purpose. When using glass fibre quilt it is recommended to turn the roll ends up at gable/ party walls for about 300- 400mm. If running quilt across ceiling joists it's important to provide runners or access boards to allow safe access at a later stage. When improving loft insulation it's even more important to ensure that storage tanks and plumbing are protected from freezing.
 
Carpenter said:
Insulation should be kept away from electrical cables (unless they are rated otherwise) and recessed light fittings. There are a number of ways to keep light fittings clear of insulation- you can fabricate small open ended boxes from MDF, ply or plasterboard, which will keep a clear space around the light fittings and allow heat to diffuse. Another solution is to use small offcuts of 6" (160mm) diameter pvc sewer pipe for the same purpose. When using glass fibre quilt it is recommended to turn the roll ends up at gable/ party walls for about 300- 400mm. If running quilt across ceiling joists it's important to provide runners or access boards to allow safe access at a later stage.
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You mean that cables should not even be run across the top of insulation as in the pics above and as I've seen them in many houses?
When improving loft insulation it's even more important to ensure that storage tanks and plumbing are protected from freezing.
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And don't insulate the area below tanks - let the heat rise there to prevent freezing.
 
ClubMan said:
You mean that cables should not even be run across the top of insulation as in the pics above and as I've seen them in many houses?
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It is sloppy workmanship and is not allow in the UK, not sure about the Irish regs.
 
ClubMan said:
You mean that cables should not even be run across the top of insulation as in the pics above and as I've seen them in many houses?
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No, sorry, I was simply reiterating your point: insulation should not be placed over cables.
 
What would be the fire hazard with electric cables being inside or in contact with fibreglass insulation ?
 
If they are underneath then overheating leading to melting and combustion for example?
 
Hi ClubMan, forgive my ignorance but I find it hard to believe that suitably rated electrical cable heat up at all never mind overheat. Do you have any links to fire regulations about this.
 
I don't know. Maybe there's something here?

http://www.environ.ie/en/DevelopmentandHousing/BuildingStandards/ (DoE - Building Standards)
 
This guide from SEI gives information on all aspects of home insulation including requirements regarding electrical cables and insulation:

[broken link removed]
 
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Thanks Capenter and ClubMan. Neither of these provide the info needed but I think the regulations are probably in 'National Rules for Electrical Installations' published by ETCI. Unfortunately this is not readable online but local library has it. Must have a look.

A bit academic I suppose since I've been doing quite a bit of googling since and there is a lot of material backing up your recommendation to not enclose electrical cables in insulation. This is apparently most critical (not surprisingly) for cables which carry large currents, eg. immersion, cooker, showers, etc and less critical for lighting wiring. This presumably would cover all cables going to sockets since these could be used by heavy load devices (eg. kettle, electric fires, etc). The general opinion appears to be that if enclosed in insulation the small amount of heat generated by high current carrying cables cannot dissipate, heat builds up and there is a risk of melting and fire.
On the other hand from what I can see fibreglass insulation is not flammable so could possibly smother flame but if the heat continues to build something more unpleasant will probably eventually happen.

It looks like I've got some work ahead figuring out how to expose there wires. I insulated my attic joists recently and remember burying cables in insulation. Cables are laid through joists and not on top so I'm a bit peeved at my electrician for not alerting me to this issue.
 
Am I right in thinking that PVC covering on electrical cables can be degraded through some chemical interaction with fibreglass insulation?
 
ennisjim,
The accepted advice is not to enclose electrical cables with insulation, unless the cables are sleeved with a plastic conduit, but I've consulted two electricians on this and they were not overly concerned about this scenario, most new wiring installations would tend to be "over designed" and there is some factor of safety built in to prevent cables coming even close to overheating. That said it wouldn't be wise to make any assumptions, especially where electricity and fire is concerned. When upgrading my own attic insulation some small cables runs were unavoidably covered with a glass fibre quilt (lighting circuits only); I consulted an electrician and he was more than happy that there was no risk of overheating, as loads were small and cable runs were short.

Bankrupt,
Glass fibre poses no problems when used in proximity to PVC sheathed cables (apart from potential overheating in certain cases); the problem arises with the use of polystyrene and pvc sheathed cables- this can cause the electrical insulation to degrade over time. This phenomenon is well known and Homebond have issued circulars to this effect in the past.
 
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