Project Insulation

January 22, 2007

Attic space

I spent all of last weekend crawling around in our attic, cleaning out 70 years of dust and laying insulation batts. Total project cost (batts, tools, safety equipment) was $570 for an 82sqm ceiling.

By far the hardest part was removing all the dust from the attic. Our tiled roof does not have any sarking installed, which increased the amount of crap that is able to find its way in. Worst of all, our original ceiling is lath and plaster, resulting in a concrete ridge every few centimetres creating nice little gathering spots for dirt. It’s worth noting that this ceiling dust is nasty stuff, full of lead and other contaminants so you may like to consider a professional cleaning service. (I’ve heard this costs about $1,500AUD and is probably the route I’d take if I ever have to do this again in my life now that I’ve proven my stupidity.)

Drywall vs wood lath plaster

First, I tried using our household vacuum cleaner. After only a few square metres the bag was full and the machine would overheat. Cooling it back down in the attic environment was difficult, making this a slow process.

Second, getting more desperate, I tried our outdoor blower / vacuum. Predictably, and not as spectacularly as I expected, it was only able to pickup a small amount of the gunk which it then promptly spewed back into the air through it’s course filters.

Dust extraction methods

I then spoke with Kennards about hiring an industrial vacuum ($68/day), which I’m sure would have worked well and is the solution a number of my friends took. (I would have done this earlier, but picking up an industrial vacuum is non-trivial when you don’t own a car.) Unfortunately, we have an unusually small manhole that the vacuum would not fit through. I considered removing roof tiles and battens, but this seemed like a high risk strategy particularly with forecasts of rain on the weekend.

So, in the end, I spent a day and a half removing many kilos of dust from the attic using a dustpan and broom on my hands and knees. I refined the process down to brushing along each 2cm x 40cm plaster crevice towards the beam, and then lengthways along the beam. This gathered the most dust and piled it for an easier lengthways brushing over the plaster ridges.

Before and after with brush

All in all, brushing was reasonably effective, but is definitely not recommended.

Compared to cleaning out all the crap, laying the actual insulation batts is fast and easy. I settled on Bradford Gold R3.5 batts, which were not at strong as the R4.0 I wanted, but were immediately available off the shelf at Bunnings.

Nathan with dust bags

Understanding as much as I could about R-values, it appears that the typical recommendation in Sydney is R3.0. The primary problem in our house is loss of heat during winter combined with 12’ ceilings, so I wanted as much protection as possible. In Sydney, we have a habit of believing we live in a warmer climate than reality suggests (hence no central heating and constant comments of “I should have brought a jumper”). BTW, don’t be confused when the US uses imperial R-values rather than metric R-values. R3.5 (metric) is approximately R20 (imperial).

The one area I still don’t understand is the use of vapour barriers with bulk insulation batts. I know that the vapour barrier is important to stop the build up of condensation. I know that it should go on the warm side of the insulation layer. But, I could never work out if I need a vapour barrier in simple pitched roof with batts on the flat ceiling. I couldn’t find any instructions for vapour barrier installation in this scenario and in the end, it appears to be something people worry about more in environments with an extreme difference between inside and outside temperatures than they do in a Sydney style location. So, I didn’t install a vapour barrier.

Batt bags

There are 4 things you need to know when buying batts: desired R-value, gap between your beams (450mm centres or 600mm centres), total sqm to be covered and how the hell you are going to get all these massive bags back to your house. The beam gap is easily measured in the ceiling and the total sqm can be estimated from ground floor level. I’d definitely suggest buying extra batts, so you can shove them in around the edges and not be stuck in the roof covered in crap wishing you’d had just one more bag delivered.

Delivery of the batts is an obvious choice, particularly when without a car the alternative is to pile them into a taxi or walk them home bag by bag. Unfortunately, on this particular night at this particular Bunnings the task was all a bit much. We got there, but only after they (impressively) called in the store expert from his holidays to help with the computer. $35 for a huge pile of batts delivered next day delivery after 4pm.

Manhole   view

Opening a packet of batts is like pulling the cord on an inflatable raft. In one of the few home handyman lessons my father has passed down, I didn’t make his error of opening them inside a small bathroom before taking the pack into the ceiling. But, our tiny manhole struck again as I squeezed, pulled and wobbled 10 packs through.

Laying the majority of your batts is dead simple. They fit perfectly between the beams and are fairly easy to throw around. Even with the recommended face mask and overalls I ended up fairly itchy on my arms, so be sure to invest the $20 in this gear. The only slight complication is making sure that you don’t cover all the electrical wiring, I just loosened any fasteners and laid it across the top of the batts.

Batts around the edges require some trimming. I bought a retractable knife which worked OK until I woke up to the idea of cutting them with a beam as the “chopping board” at which point it worked brilliantly. Our roof has a fairly high pitch, so even laying in the corners was not too difficult.

Laid batts

Basically, with some preparation (i.e. buy batts & safety gear) and a little determination you should be able to completely clean and insulate your ceiling in a weekend.

One week later I’m finally able to kneel down again. More importantly, over the 40C weekend our house stayed cool during the day (great) and then relatively hot at night (not so great, but proves the effectiveness of the insulation).

Comment by Vacuum Cleaner on July 12, 2007 5:21 AM
Wow. Quite a tale. But also quite a useful explanation of the overall process. I have been considering doing my own attic for a few weeks now, but haven’t gotten up the courage and/ or energy. While you certainly gave me a good sense of how to do it, just reading about your experience wore me out, so I’m not sure if it did anything to get me over the hump to actually do it. Part of my problem, though, is that my attic is currently filled with boxes and boxes of stored junk, which, judging from your post, you didn’t seem to have to deal with. Not only will I have to move them all out before I can start the task of cleaning the gunk and laying the insulation, but once I’ve gotten them down, I can’t just leave them there, or put them back in the attic as they were. I’ll have to sort through them one by one and figure out what I can get rid of. Then I’ll have to hold a garage sale and put together packages to take to the goodwill drop-off point. All in all, it seems like a project that will require true commitment, and I don’t know when I’ll be ready to make that.
Comment by Nathan @ e-gineer on July 12, 2007 5:46 AM
Although I get a huge sense of satisfaction everytime I can dispose of old junk, I don't envy your storage removal task...

If you are feeling demotivated, just remember that the whole (epic) tale was completed in a single weekend and that only halfway through winter it has already made a huge difference to the warmth of the house. Unlike last year, we don't need to hand out polar jackets when people come to visit!
Comment by oil paintings for sale on April 30, 2008 7:38 PM
You did all of those by yourself? Cool! You’re wife is lucky to have you. I think it’s high time for you to start a Do-It-Yourself or DIY site for dads at home. It may contain projects which you’ve done so far so that dads can learn how to do thing on their own especially during weekend or when they’re on vacation.
Comment by AK Wong on June 10, 2008 12:16 PM
Hey, just stumbled across this post. Thanks for the detailed story, it was a great read! It just confirmed that I couldn't be bothered doing it myself though, so I'm going to get my insulation installed instead :-)
Comment by Anonymous on September 22, 2008 5:35 PM
Interesting read. I'm about to tackle this project myself but at this stage am still looking into what I'm going to use, i.e. Wool V Synthetic. Did you do any research into that topic?

Also, how did you find reaching into the far corners of your roof? That alone is almost enough to pay the extra cost of installation.

Comment by Nathan @ e-gineer on September 22, 2008 9:49 PM
@MK: I'm lucky to have a fairly high pitched roof so the corners were not too problematic. For me, this installation part was still very easy relative to the cleaning task.

I did research the material type, but quickly became overwhelmed and decided to go with the mainstream brand / solution available at my local Bunnings hardware store. My main concern was ensuring the highest R-value that I could easily obtain.
Comment by IT Certification on January 31, 2009 11:06 PM
Great post in real. I really love both the comments and the blog itself.
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