Insulation rolled over cables.

eamon11

hello Folks,

30 yr old house with very little attic insulation. The attic however is full of cables an wires all over the place. I mean, there are a lot criscrossing all over, many comiong up from each room. Junction boxes etc. The house had a few owners so maybe each one did their own bit of wiring. To put the insulation under all of these cables is nigh impossible. Ideally it would all need to be rewired neatly. However in approx 2 yrs I will be redoing it anyway as I intend to put 1 or 2 rooms up there. Its a 150 m2 bungalow with a very large attic.
So, my q is, can I roll out the fiberglass over all of this for now or would that be dangerous?

thanks,

eamon

maddragon

No one is going to advise you to do it but if all the electrical wiring is sized properly and has the plastic covering (not the old rubber insulation), then it should be ok.

DublinDilbert

Its not normally an issue putting some insulation over electrical cables, provided they are correctly sized. I would be more concerned about the junction boxes that are up there.

I would check them (or get an electrican in) to verify they are all sound and maybe get rid of some of them. There can be valid reasons to use a junction box, but it can because someone is being lazy or doesn't know how to do it correctly.

If it was me i would get the junction boxes removed then put down the insulation, but that's just me. i'm sure there's many a house where they just throw it down on top and its fine.

paddy147

+1 for checking the junction boxes (and removing them if at all possible)1st,before putting down insulation.

Carlow52

OP what happens to all the fg rolls in 2 years when u start fitting it out, it will be a mess.

Then when u do the rooms how will the roof be insulated?

I would address this now rather than just horse on fg willy nilly and then have to unscramble it later

DanWall

Could you not get rockwool etc and pour it in, then level it.

eamon11

many thanks lads for the replies, appreciate it.

Carlow, it would be hard to wire it neatly now as I need to work with the carpenter and electrician in 2 years to see where exactly all plugs, lights etc are going. The rooms need to be in construction first, then the whole attic space wired properly.
Regarding the insulation afterwards, I have seen a work colleague s house where he did something similar. The roof and walls of the new rooms wouls be insulated on the outside. The fiberglass around the edges would remain where it is. The house roof (between the rafters) would remain as it is. Uninsulated.
Can u see a problem with this?
Danwall, Im not sure I understand correctly. Is it not the same thing rolling the insulation as pouring it? Bear in mind it will need to be removed in 2 yrs anyway and it might be easier to roll it up rather than have blown stuff in there.

Thanks again

MicktheMan

eamon11 wrote: »

So, my q is, can I roll out the fiberglass over all of this for now or would that be dangerous?

Leaving aside the increased fire risk, there is no point in insulating over the cables leaving a space beneath between the insulation and the ceiling. Do it properly or not at all!

MicktheMan

eamon11 wrote: »

Regarding the insulation afterwards, I have seen a work colleague s house where he did something similar. The roof and walls of the new rooms wouls be insulated on the outside. The fiberglass around the edges would remain where it is. The house roof (between the rafters) would remain as it is. Uninsulated.
Can u see a problem with this?

Make sure that whoever is doing the building work are fully informed on airtightness have experience in making a house airtight and have actually witnessed an airtightness test (on a dormer).

JMSE

airtightness, dont all rooms have vents??

/rings asthma association!

MicktheMan

JMSE wrote: »

airtightness, dont all rooms have vents??

/rings asthma association!

Yes, of course, a house must have an appropriate ventilation system and/or strategy.
However, there is a major difference between air infiltration (aka draughts) and good ventilation. My point earlier has to do with ensuring that airtightness has been considered, not just insulation as this is a major weakness in the heat retention properties of a house, especially dormers. Imo, anyone contemplating either building or renovating nowadays must take insulation, airtightness, ventilation, thermal bridging, heating system & control into account (i.e. a holistic view) rather than concentrating on one or two and forgeting about the rest if they are serious about creating a healthy, comfortable and affordable house (to heat).

eamon11

thanks lads,

I think I will do ur idea maddragon, dubdil an micktheman an sort out the junction boxes an roll it over the cables.

Cheers

Radiotower

If you roll insulation over cable then there will be an air gap between the plasterboard ceiling and the underside of your insulation allowing the heat to escape from the rooms. The insulation should be fitted between the ceiling joists on the plasterboard - a similar situation arises if you roll the insulation across the ceiling joists (wool bridging). You can roll another layer on top of the insulation fitted between the joists to have the required depth of insulation.

Do not block the eaves - you need to allow ventilation into the attic space to prevent condensation and mould growth. It is ok to cover most electrical cables with the exception of High Powered cables (Cooker, immersion, electric shower). These should be above the insulation - if there is not sufficient slack to allow this then leave a 3" gap around them. Also do not cover recessed ceiling lights - leave 3" gap around them also.

Don't forget to insulate the cold water tanks and pipes in the attic as less heat from the rooms below will escape into attic space so there is more chance of them freezing in cold weather. Usually you don't insulate directly underneath the cold water tanks allowing some heat to underside of tank to prevent freezing.