Canaboid Registered User

I've moved into an old semi D with bugger all attic insulation so it's going to be an itchy weekend for me.

Does anyone have recommendations for the best type of insulation to use and where to get it a a reasonable price (south Dublin).

Any other tips on installing are greatly appreciated.

noby Registered User

If you're using the rolls of fibreglass insulation, cut the rolls to the width of your ceiling joists. Any old saw should do it. Then when you roll them out, they'll fit snugly between the joists. Oh, and be sure to leave a gap at the end for ventilation at the eaves.

CJhaughey Registered User

Rockwool is way less itchy than the fibreglass.
I used a long knife to cut it which didn't make as much dust as the saw.
the saw will be wrecked very quick cutting the insulation so get a cheap one if you use this method.
Get a "noddy suit" one of those disposable overalls that cost €5-00 each and wear it.
At the same time get a moldex dustmask they are great and will stop you hacking and itchy throat.
and one more thing a pair of long gloves -marigolds etc worn under the suit.
away ye go!!

Canaboid Registered User

Thanks guys. Is there a difference in price/effectiveness between rock wool and fibreglass ?
Any ideas on the best place to get this, I'm thinking B&Q/Atlantic is there likely to be cheaper available ?

CJhaughey Registered User

Rockwool is more expensive, try Capco CPD they can give good prices.

fintan Registered User

If you want to a greener solution try something like thermo hemp

It does cost a little more than rockwool, but has won awards plenty of awards and is 100% pollution free.

There are other people making insulation from hemp, so shop around

Muggins Registered User

Any recommendations on where to buy the ThermoHemp in the vicinity of Cork city ?

fintan Registered User

First place you should look muggins is the Sustainable directory

Muggins Registered User

I checked the link but could find any info on Thermo hemp. I also googled around but can't find any Irish based info. Any leads would be appreciated.

Victor Registered User

Do not insulate without thinking things through properly or you could end up with a rooted roof from condensation. Make sure the attic is properly ventilated.

fintan Registered User

Sorry the link was of no use to you is the Irish company behind thermohemp give them a call, Im sure they can arrange samples and delivery to Cork

KAGY Registered User

I'd us a garden shears to cut insulation
In the current building regs (which don't actually apply to 2nd hand houses unless you're modifiying them) they suggest 150mm fibreglass or equivelent between the joists and min 100mm across them.
If you have a header tank in the attic you should remove any insulation from under it to stop it freezing in the winter, but insulate around and above it. You could use 100mm expanded ps to make a box from the ceiling level up, over and around it.
One small point about place insulation across the rafters is that you will have difficulty walking on them, it is suggested that you provide some form of walkway to the header tank
And don't forget to leave a gap where the roof meets the wall to allow ventilation and prevent condensation rotting your timbers.

GreeBo Registered User

Hmm I have the attic insulated between the rafters and then most of the floor area is floored with the usual chipboard.
I wasnt aware that laying across the rafters was also advised.
Doesnt that kinda render your attic useless?

Victor Registered User

One small point about place insulation across the rafters is that you will have difficulty walking on them, it is suggested that you provide some form of walkway to the header tank
You are thinking of joists. Joists are horizontal, rafters slope.
Doesnt that kinda render your attic useless?
Depends on what you want your attic for. Some attics are too small for storage.

Sleipnir Registered User


with the recent temps I have also decided that I need to reinsulate.
At the moment there is no insulation on the roof at all (just the floor of the attic) so I definately need to do that.

Also, the dirt up there is unbelieveable (i.e. you can't move anything without a being smothered in a cloud of dust) so I was wondering if it would be a good idea to put plastic sheeting on the inside of the roof tiles between the rafters, then insulate and then cover with marine ply? Or would this this screw up the ventilation?

Does anyone know how much that hemp is per sqm/sqf?

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