In-ceiling insulation

Does anybody have any experience with this?

It’s brrrr degrees in Johannesburg today. I’ve been thinking about insulation in the ceiling for some time, but maybe this time I mean it.

So does it work? Is it worth the money or is it cheaper to just get more heaters? There are different materials available - some of them look to me like they might be a fire risk, which means insurance premiums go up.

Finally, because I have roof top solar, I must have cables coming down through the roof into the ceiling space. I suppose these guys can work around that, if they’re forewarned, but I have visions of cowboys going in and displacing everything in their way.

I’ve done ceiling insulation at a previous house. It definitely works. The house was cooler in summer and slightly warmer in winter.

In that house, I had a living room with a pine ceiling and only 40mm between the ceiling and the tiles: No space for blow-in insulation and no cheap options.

So I did what every cent-turner does, I insulated the rest of the house and left that part for later… and then sold the house without every doing it. This caused a rather interesting situation: Just walking from the living room into another part of the house was so noticeable that you’d think AC was involved, while it wasn’t.

Materials-wise: The blow-in cellulose is treated to not participate in a fire (ie it burns, but not on its own). I would not worry about it. I know polystyrene sheets are also a popular material, but with those you have to be careful, some variants will melt and participate in a fire, and the last thing you want is molten plastic dripping from the ceiling while everything is on fire.

I can personally recommend eco-insulation, its a blow in product.

The insulation reduced the inside temp in summer by roughly 10 degrees and in winter its roughly 7 or 8 degrees warmer than before.

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I used the same product.

It’s cheap and worth it. Another benefit is that it stops a lot of noise from the outside. I went with IsoTherm (thickest), and would use the same again.

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I can recommend Isotherm, the thickest one, think it’s 140mm.
Because of no stock I didn’t do two of our bedrooms with the rest of the house, then only got to it 3 months later, during those 3 months you could clearly feel the difference when walking in to those bedrooms, I never measured, but they were definitely a lot hotter than the rest of the house, this was during summer.

Thanks all for your input

Glass wool regulations are 270mm minimum in Ireland.
Every house has double glazing as well.
They never used to be ( the old regs) but a freeze burst a pipe whilst I was in SA on holiday.
It was a big insurance job to fix, but where the ceilings were repaired the contractors installed 300mm. In the unrepaired ceilings was just the existing insulation ( thinner glass wool).
You could tell which rooms were which afterwards.

I had experience with some blow-in paper pulp-like product, that didn’t impress me.
The good numbers didn’t seem to match performance.
Drafts blew it about so it was uneven, and I didn’t think it performed great.
Glass wool is very good. I didn’t going so thick was needed, but I’d do that again.

In another house I made an enclosed lounge out of a stoep.
The roof was such that there was only about 6 inches clearance between the tin roof and the ceiling. I had some huge sheets of scrap polystyrene, ( the old ceilings which I was replacing were actually polystyrene).

So I layered it all in that 6-inch cavity and hoped for the best.
That room was the coolest in the house. So that stuff impressed me the most.
I may go in for double-glazing in that room, when I get back.

Well it turns out the house was insulated with something called aerolite which, I understand is a fibre glass product, and which (I’m told) has collapsed. It certainly isn’t keeping us warm.

Interesting when the guy was up in the roof today I could see through the trapdoor and the light shining on the roof tiles from the outside revealed nice, regular rows of openings.

Now the different companies quoting me come with different stories. One is willing to remove the old aerolite for a fee. Another tells me that it’s best to let that sleeping dog lie because if it’s removed you will have little fibers all over the house and so he just installs (isotherm) over the old insulation.

My parents have the old pink Aerolite installed. It does collapse. It traps a lot of dust. Working in a roof with Aerolite is terrible, absolutely terrible. Wear a dust mask.

Leave it alone and put something else over it. Even collapsed, it still has insulating value.

More than ±15 years ago, I first used eco-insulation

Richard there, has always been my “go-to” guy for insulation. Helped me with damn good products and advice over the decades.

So we had PVC ceilings installed. Best thing EVER!!! Dripping water (for whatever reason) “be gone” with rhinoboard ceiling replacement.

HOWEVER … if you install PVC ceilings, better they are installed to allow Eco insulation products, or the PVC ceiling boards tend to sag over time.

Bugger me …

So I’m looking into this now, seems I have to go Aerolite Ceiling Insulation (5000 x 1200 x 135mm) cause we moved house … DAMMIT … I should have had that installed +10 years ago.

Why? We are now living under the solar panels with the Cape Town Cyclone that went through on Sunday, North North West Facing roof/windows. At times I thought the panels, furniture and wife will blow away if this roof comes off.

Liewe moses.

I agree with this, don’t do it yourself, it is really horrible stuff to work with.

The new model Aerolite, can install it with your hands.

Was going IsoTherm, apparently it is less efficient, not designed for right under a flat roof, and not SABS approved anymore.

Had a section that also collapsed, the old tech aerolite.

It is in the roof still.

Why, to remove it, bar the challenges, it costs a pretty penny to dump it too. So yes, leave it well alone in there.

My situation was a bit different. I bought mine years ago from an auction when the prefab construction village for the Majuba power station was taken away.
It was rebagged and R1 a roll, (all the dust was free). I could have ( and should have) bought 10000 rolls, there was that much of it for sale.
A lorry to transport it would have been the costly part.
The lads I had that re-installed it in my ceiling, well let’s just say they were not the type to complain, and they complained bitterly. They really complained.

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Just another thought on insulation … more to keep the heat out.

Have a braai room, low ceiling, beams. In summer, man, it is a exceptional “cozy” area.

So, me, box, what box … had the polycarbonate roof sheets replaced with, wait for it … WHITE IBNR roof sheets with that shiny underroof insulation you also put in to keep the heat in.

No additional insulation needed … problem was solved.
Warmer than our house currently as a matter of fact.

The one and only trick … better you don’t live above that roofs heat/light reflection … :slight_smile:

FWIW, it is a very low roof, below ground level. “Stupid” first owner dug the house out to get it level, stupid stupid … they never put in the proper retainer walls nor water diversion techniques.

Nou sit ek met die twak.

The only thing the old Think Pink insulation is good for these days, is for when installing a built in braai / fire place, because it’s the only proper insulation which can take heat, ±500 degrees if I remember.

Appart from that it’s horrible, horrible stuff which should be avoided, literally, I sommer got a itch now.

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I am inclining towards this company, mainly because they are by far the most thorough and professional company I have dealt with. I’d have thought I had a queue of people wanting to go up into my roof and have a butcher’s, but no… most of them just asked how many bedrooms, how many bathrooms and said “must be X m2” and then wouldn’t quote because that’s just an estimate and they might find it’s more or less when they get here.

Eco-insulation actually walked around the house with me, noted the position of the downlights, went up into the roof to check the hot water pipes and the geyser insulation (which has collapsed). They noted our downlighters and said they had special collars to fit around those. They actually measured.

Challenge them on something and they’ll give you the reasons they are quoting for that item.

I am really not keen to do business with somebody whose first sight of my house, let alone the inside of the roof, will be when they arrive to install.

I’ve used Eco-insulation twice now. Of course this also depends somewhat on the team in your area, so this might not be the same everywhere, but what you describe was also my experience. They have little hats that goes around your downlights, and they have to insulate under the geyser too, so they look at that as well, plus they make a little pouch that staples to the trapdoor in your ceiling as well.

The installation itself is not too difficult. The guy who drew the short straw that morning goes into the roof. Then the move some roof tiles (if it is a tiled roof) to get the pipe in, and then it’s a floodfill process after that. They do a 3/4 bedroom house in about two hours, maybe a little more.

I installed eco-insulation in 2013, and we had a geyser burst in 2018, which took out some of the ceiling and dumped that mess on the floor in one room. That is one downside (compared to the alternatives). All the insulation had to be redone after the ceilings were replaced, which was unfortunate… but… from that I could also see that the product had hardly “settled” at all in that 5 years. Probably not the longest test period, but something.