Ceiling Insulation

[Alfred]

I just bought an old house and went up into the roof to check it out. To be expected, it was full of dust and leaves and I was wondering if any of you have actually changed the ceiling insulation in your own houses before? Is this best left as is?

[Gumby]

Too many leaves would worry me on a couple of fronts. Fire and access. How are they getting in?

The original insulation doesn't really wear out so i see no reason why it would need to be changed. If it's not up to the job, maybe add some more bats yourself over the top. You could buy lower grade and cheaper bats for that job.

[Markw]

My house was only partially insulated - about a third, with little squares of that horrible pink fibreglass crap.

As we are going to use some of the larger roof space areas for a bit of storage, I removed the old insualtion and a lot of the dust and installed new insulation. The stuff I used was white polyester bats (Dacron) at $52 per bag of 6m sq. I have also installed about 26m sq. of 19mm pine board flooring for storage and access. Its easier to get to awkward places if you got someting to crawl over rather than the ceiling joists.

The dacron bats are great to handle, no itch but can be a little difficult to cut to size. As for their ability to insulate, our recent hot weather certainly tried them out, and I reckon they worked just fine.

Polyester bats are not the best there are - number 10 on the list - see this site
http://www.ais-group.com.au/homeinsu...ive_survey.htm

but the ease of handling and no itch makes up for any loss.

BTW if you decide to remove any old insulation, do it in winter when wearing a tyvec suit and respirator wont cause you to dehydrate from the heat.

[Alfred]

Thanks for the replies. I think I am going to replace my insulation and try to get rid of as much of the dust as possible. Right now I am trying to decide between insulation in bags or in roll form. Will check out the Dacron stuff. Thanks for the link.

[Markw]

Alfred,
Just be aware that the dust in your ceiling will probably have a high lead content. Lead from decades of car fumes either settles on the roof tiles or is dissolved in rainwater then deposited of roof. Wind blows the dust under the tiles and is left in the roof spaces.

Also there will be the fibres from the old insulation. Whilst the current thinking is that the fibres are relatively harmless when breathed in, why take the risk. The said that asbestos and DDT were harmless too.

As both of the insulation fibres and the lead dusts are particulates use a P1 class disposable respirator or what most people call a dust mask. Make sure its Australian Standards approved (5 ticks) and shows a P1 compliance.

[Wildman]

I would also have the entire roof cavity vacuumed out before you put new insulation back in. I did, it cost me a couple of hundred dollars and saved a whole lot of hassle. If you just take out the old batts, let the vacuum guy do the rest. The guy that did mine had a truck mounted unit with a 3" hose, easily enough to pick up leaves, dust, left over insulation and rat carcases. I then had loose fill cellulose fibre insulation pumped in. Was cheaper than batts and I didnt have to get in the roof to do it myself. Seems to be doing a good job so far, has been in 12 months.

Cheers
Ben

[Alfred]

I never even thought of lead, hmmmm........... Called a couple of roofing folks today and they said they use a vacuum system to remove everything, batts and all! Getting a quote today.

[RufflyRustic]

Hi Alfred, could you keep us posted on this as I'm finding it most helpful.

cheers
RufflyRustic

[rmcpb]

I never even thought of lead, hmmmm........... Called a couple of roofing folks today and they said they use a vacuum system to remove everything, batts and all! Getting a quote today.

Must be a hell of a vacuum system to get the bats and all but sometimes its the way to go with old stuff. Doing things yourself is great but, like the problems with removal of fibro, old insulation is a problem that is worth getting someone in to do for you. No good saving a few dollars on the job only to wreck your health.

Keep us posted of your progress.

[Alfred]

Okay, got a few folks to come in and quote and should have them by tomorrow, will keep you posted. Have to run!

[Alfred]

I have seen several folks and have quotes in hand and have decided on a company called Cool and Cozy.

It is a spray in cellulose insulation that is sealed on the top to prevent it from flying around when the wind blows. The light fittings and fans etc are shielded and not covered over and it is supposed to be more effective then the normal batts or bags as there are no gaps at all.

The only down side I see is that some of the wiring will be buried, but they offer a free top up and seal if ever any work is required, where the insulation has to be moved.

I chose this type of insulation because the installer said that he would seal the gaps between the conice and the feature brick wall and the topseal would prevent any dust from actually getting into the insulation itself.

Cost wise it is about the same as Decron.

Hope I am making the right choice.

[Markw]

Alfred,
I do remember reading somewhere that unless the house was of recent make (may have been mid 80's) or recently rewired, the wiring must be sited on top of the insulation instead of underneath. This was possibly on the insulation bag instructions.

This is to do with the wiring insulation's capacity to dissapate heat. The newer types of insulation are thinner yet still provide the electrical insulation value thus being able to get the heat away faster in to the air surrounding the cable (convection).

Burying old type cables will prevent the heat dissapation and could cause roof fire. When I installed the batts in my roof I made sure that the wiring was above the batts even if I had to do a bit of disconnecting and re-connecting irrespective of wiring age as much of the wiring has recently been replaced.

Might pay you to discuss with insulation supplier first.

[phyllis]

I would also have the entire roof cavity vacuumed out before you put new insulation back in. I did, it cost me a couple of hundred dollars and saved a whole lot of hassle. If you just take out the old batts, let the vacuum guy do the rest. The guy that did mine had a truck mounted unit with a 3" hose, easily enough to pick up leaves, dust, left over insulation and rat carcases. I then had loose fill cellulose fibre insulation pumped in. Was cheaper than batts and I didnt have to get in the roof to do it myself. Seems to be doing a good job so far, has been in 12 months.

Cheers
Ben

Wildman, can I ask which company you hired to vacuume out your entire roof cavity ?

[Wildman]

The company was Vac-Attack. I think his mobile is 0409 509 649
I had urea formaldehyde foam insulation in the roof which it just sucked out with no problems. Price was about $8/square metre but it was worth every cent.
Cheers
Ben

[limbsintact]

I have a similar problem in Melbourne, 150 m2 of roof space, it's filled with fibre glass insulation that is in wads and has packed down (probably has gone from R3.0 to R0.5). I've decided to have the roof cavity vaccumed before putting in new insuation. I've got quotes from around $8-$11, they say if you have a slate roof (which I have) it costs a bit more as the slates over the years breaks down, falls as flakes and chunks and block the vaccum (4" pipe !!!!), and so alot of it involves them removing it manually and then just vaccuming the rat carcasses and dust.
And yes, wiring specs from AS 3018 (domestic installations section 6.4) seems to state that wiring has derated current ratings when surrounded by insulation.
When cleaned I'II be replacing the insultion with r3.5 polyester bats, so if I want to add downlights, extraction fans, etc, it will be easier and cleaner.