DIY Tips and Tricks to install insulation Batts yourself.

Helpful Tips to install Insulation Batts in your Ceiling this Weekend!

Ten things to Prepare before you start installing roof insulation batts


Installing roof insulation batts is a difficult and dangerous job and the following tricks and tips should not be considered as an endorsement or recommendation that you should install your own insulation. I would strongly recommend that you only use trained professionals to install your insulation batts.

However I do understand that some people starting out in the insulation industry are not given any training from the companies hiring them and so this is intended for the people who want to be professionals and are looking for advice in a unregulated industry about how to safely install roof insulation.

Health and Safety is number one when installing home insulation

Firstly this is a physical job, if you are not fit and healthy do not attempt this job, it is just to demanding and if you faint in a roof you will fall thought the ceiling and you may have a fatal injury. I would also make sure that I did not attempt this job on a day when it is going to be hot in your roof space. I have experienced 83 deg Celsius temp in a roof when installing insulation and actually burned my skin under my shirt from baking in the heat.

Next you need to have the following safety equipment and preparations

  1. Weather Pick a cool day and start early but because you left this job until the middle of summer to start doing it, the best time to start might be at 3 am in your roof when it has just cooled off from the day before. I recommend putting the batts into the roof on one day and then tossing them out before laying them the next. If it is raining that would be a great time to do the job as long as you can access the roof though the manhole and you put the batts into the roof on a dry day previously. If the day temperature is forecast to be more than 30 deg don't even attempt it because by 8am it could be as hot as 60 deg Celsius (I assume all the people with cool homes in summer are not wanting insulation)

  2. What Safety clothing should I wear to install batts?, Fibre Glass batts are Itchy !! Do not believe the packet... lol Wear a disposable painters overalls during the job and you may need to buy 2 or 3 of them because they will get ripped and torn easily. They are also hot and that is why starting early is important. I recommend wearing good shoes in the style of joggers, Dunlop Volleys are good on the roof but inside a ceiling the dust quickly fills the tread and they become slippery. I always wear a shirt in the roof to keep spiders off my back while I am working and stop me getting bad splinters. I don't recommend Jeans because they restrict movement and they are hot. A good set of soft leather gloves might be a good idea but they do get hot and so I never wear them.

  3. Respirators - Buy yourself a proper $30-50 dollar breathing respirator (Silicon ones are better, I use Sundstrom SR100) and wear it while you are in the roof the whole time. Yes the actor in the photo on the pack of batts has one of those crappy paper masks on but they are useless if you actually want to protect yourself from harm. It is worth the extra money and maybe in 20 years time you will not have to worry if the lead dust in your roof or glass particles from the batts have hurt your lungs. At the end of the job just have a look at the front of your mask and you will see it caked with glass fibres that would have gone into your lungs. The dust in your roof cavity is dangerous.

  4. The number one best friend is a LED head lamp - these are a great advancement, I have used these Energizer LED head lamps for years now and they are the best for making sure you can see properly while in the roof. I use the Hard case Rugged version.

  5. Electrical precautions when installing ceiling insulation batts, I recommend turning off all the power circuits at the power board to your home while anyone is on or in your roof. Remember to put a pad lock on the box and put the key in your pocket so nobody can turn them on while you are in the roof space. In Queensland in 2009, four people died because they did not do that before climbing into the roof. It happens all the time because average people are not trained to watch for live wires in a roof.

  6. Always have one person on the ground that can call for help if need be and that can call out to you though the plaster downstairs to check on you from time to time. That person should be able to track you downstairs as you move though the roof (don't stand under neath the person in the roof). It is a good idea to have two people in the roof too, as they can assist in spreading the batts and it is a extra set of eyes to spot dangerous timbers or nails as you move.

  7. It is possible to become physically stuck in tight corners, just because you can climb in does not mean you can turn around or climb out again, I have had to have roof sheet and tiles removed on a number of occasions to get people out of tight areas in the roof space.

  8. Have someone hold the ladder for you as you climb in and out, they have them pass you the tools that you need. The golden rule is one hand for the job and one for the ladder. A lazy man climbs a ladder with both hands full. Please follow the safety instructions for setting up your ladder properly, many a person has fallen off a step ladder in this industry and never walked again.

  9. Wear a hat in the roof, it will soften the blow every time you hit your head but the other trick is move slowly... then it will not hurt as much when you do hit your head. It will also stop some of the splinters of timber getting into you as you move around.

  10. Stay hydrated, don't worry about energy drinks, you loose to much water for that, just drink about one litre for every 30min you are in the roof if it is a hot day. I would often drink 20 to 30 litres of water in a day during summer in Queensland. Of course to much water without salt is toxic and can cause a heat attack, so make sure you eat some regular salt if your muscles start to cramp up. If you do start to get leg cramps that is a sure sign that you need to leave the roof and eat some salt or salty food if you do not like the idea for table salt. Remember if you get a bad leg cramp in a roof you might start falling and so the best thing to do is grab anything you can on the way down. If you can not grab anything, stiffen up and spread out as much as you can. I have fainted in a roof before and I fall right on my back but because I stiffened up as I fell I did not even break the plaster. Then I got up and kicked myself for not following Rule number 3 of the next section.

  11. Keep your eyes open for dangers at all times, you will find snakes, possums, red back spiders and even porno magazines in the roof. Of course the last one is not so dangerous but it could still have your eye out.

  12. Do not cover any heat source with insulation batts, including, down-lights, transformers or exhaust fans. Read your local regulations in relation to installation standards but in Australia, there must be 50mm gap around any heat source like a light or transformer and 300mm gap around heater flues or chimneys.

  13. Know when to leave it to the Professionals, If your roof is low pitched, Fibro, metal tile or has any raked, exposed beam or split levels, leave the job to the professionals you will not get it right because 90% of the professionals don't even get it right. Oh and if it is a steel frame home don't waste your time with batts at all, Follow the link to find out why Fibreglass batt insulation just does not work on steel frame homes.

Basic Tools you need to install home insulation batts in your roof

  1. Disposable overalls

  2. Soft leather gloves

  3. Retractable blade knife, do not try to cut batts in the roof, tear batts into shape if need be. Never cut on a surface that may have a power lead under it.

  4. Step ladder, locked into position

  5. A stick or PVC pipe with a screw though the end of it to poke batts out to the edge and into corners.

  6. LED head lamp

  7. Lots of cold water ready for when you get out, actually room temperature water is better

  8. Good pair of joggers (shoes) that has good tread on them and flexible souls

  9. Garbage bag to put the rubbish plastic in as you open the packs in the roof

Rules for moving in a Roof cavity without hurting yourself.

  1. When you are in a roof the plaster is deceptive, it is very brittle and weak. Keep in mind that if you fall though, it may not be just a matter of falling on the floor. You might fall on an office desk with one of those receipt holder spikes that goes right though you or you could fall down a stair well that is bellow you.

  2. Never Rest anything on the plaster, it will break. That includes the packs of batts, make sure they are laid across the joists and not in the bays on the plaster ceiling. Also don't sit on the packs when they are in the roof, the extra weight will be pushing on the plaster.

  3. Always have 3 points of contact in a roof when you move though or even when you are working with 2 hands, lean a knee agains something to make the 3rd point of contact. Your life may well depend on it. This is the number one cause of damaged ceilings by people walking in your roof space. This one rule could save your life.

  4. Never twist or slide your foot on a joist. You can not slip off if you are sure footed and do not twist or slide your feet while in the roof. I think this is the number 2 reason why people put their feet though ceilings.

  5. Never stand on the batten timbers, they are not made to handle your weight, if your joist spacings are more than 900mm wide bring a timber board into the roof to lay on as you move though. It should be at least 2m long.

  6. Always be sure footed in a roof, never just step like you do on the ground. In a roof you might be stepping on some rotten timber. I have gone to step on a timber that looked perfect and strong but it was fully eaten by termites on the inside and it just cracked to bits when I tried to put weight on it. I have also had timbers that are plain not bolted on at one end or actually cut in half by other trades trying to get access. Avoid a costly fall by having 3 points of contact at all times and testing every step before you put weight on it.

  7. Do not stand on anything other than the joists. Many newbies to roof work will stand on timbers that have been left in the roof or plastic bags laying on the joist but that can be super slippery. Even timbers that look like they are meant to be the path to walk on, always stand above the joist on that timber and only if it is properly attached to the joist.

  8. You will cut yourself on nails, screws and gang plates, when you do just remember that there is only 16mm of plaster between you and the kids down stairs and although you can not hear them very well they will hear you. Don't teach them any words that you do not want them repeating to mum...

Selecting the right Batts for your roof 430's or 580's ?

Ok so if you do not know already Roof insulation batts come in two standard widths and if you get the wrong ones delivered, you will be in a world of pain trying to fill all the gaps for them to work properly. The right thing to do would be to lift your manhole and just measure the distance from the start of one joist to the start of the next one, this should either be approximately 1200mm, 900mm , 600mm or 450mm. Of course that includes the timber and so when you take the width of the 50mm joist timber off you normally end up with something that will be best served by a 580mm wide batt or a 430mm wide bat.

Now there is a trick to this that works 95 percent of the time without looking in the roof and that is why we don't need to inspect your roof to do the quote. Basically a corrugated Iron or Colour bond roof will be 900mm between the joists and take two 430mm wide batts side by side to fill the bay and a Tile roof or any kind will be 600mm between centres and take a 580mm wide batt. The exception to the rule is old Queenslander iron roofs that often have 600mm centres or on odd occasions 1200mm centres (normally small low pitched iron roofs)

How to get the insulation batts into your Roof ?

Getting batts in though the manhole is the safest way for the DIY person but for the Professional, you should definitely learn how to handle lifting roof sheets and tiles to gain access to put packs of batts into a roof.

There is a lot of safety aspects to be considered when climbing on a roof and so I am not going to cover that here. Basically if you lift the roof you let in more light and let out lots of heat. It is also far easier to physically get the packs into the roof.

On a tile roof you will need to cut the batten timber on one row and lift out at least 6 tiles. For roof entry I normally create one entry point for every 100 meters of roof approximately unless it is one big open cavity that is easy to transport packs inside the roof space.

Assuming you are using the manhole you will need to make sure you have a manhole that is big enough for your average pack size and that there is at least 1.2 m of clear space above the manhole in the roof for you to pull the pack into. I assume you did all this before you ordered the packs to be delivered to your house ? Anyway, expect the packs to be tight but generally you will need a 550mm square opening. Much smaller than that and you will need to pass them into the roof 2 batts at a time witch will turn a 1 day job into a week long nightmare.

If you are pulling them into the roof you need one person on the ground to pass the pack up (with the opening of the pack going in first as it is easier to grab in the roof). The person in the roof needs to grab each top and pull it straight up in one movement while the person on the bottom keeps applying upward pressure. If you let the pack fall back and pull it up again, this action will break the skirt out that holds the manhole cover in place very often. So just keep upward pressure on it. Then when it is nearly all the way up you can pull the pack over to get the last bit though.

Once the pack is in the roof move it up the roof as far as you can while leaving it in the middle area of the rafters. Do not split the pack and start laying the batts until you get most of the packs into the roof. I normally leave about 10% of the packs on the ground just in case I don't need them as I always bring extra packs to what I need on my measurement.

Speaking of the amount of insulation packs you will need the measurement is on the bag for the coverage, this measurement normally allows some reduction for the amount of timber joists in your roof (about 6%) but it is better to have one pack left over than have to drag a pack of itchy wool home in your car because they did not deliver enough. We measure all our customers houses from the aerial drone photos and it is very accurate, you will need that measurement before you place your order if you are doing it yourself.

Plan of attack for spreading the insulation batts out quickly

Ideally this is a two person job to install batts in your roof and so this is the basic system I follow in every roof. First thing is to get the packs in the roof but then you need to spread them out while still in the packs.

The batts will be very hard to get into the roof in one go but if you can it saves getting out and back in again. Once you have climbed out of the heat a few times and cool down you will realise that every time you get back in it gets harder to climb the ladder .... So less times up and down is better

Each pack will have about 8 - 14 batts in it, after you cut the first pack open you will know. Then start cutting packs open one at a time and toss two batts out to the edge in each bay around the out side of the roof. If the house is very wide you might want to put two groups of two batts. The idea is that you put enough batts out to cover the area of each bay while still standing in the middle section of the roof. Do this all the way around while the other person climbs out to the edge with the stick in hand and pushes all the batts into place.

Work around the roof edges in one direction until all the batts needed are tossed out and then climb into the edge to lay the batts back to meet the other worker as they follow you around. You should be able to toss the batts out at twice the speed of the person laying them and if should end up that they do about 2 corners and nearly the 3rd one by the time you work back to them.

Then repeat the process for the middle area of the roof and your done. Sounds easy right...

Key points to installing insulation batts that work

  1. Make sure every gap is filled and all the corners, just one percent gaps reduces the effectiveness of the batts by upto 30%

  2. Make sure you do not cover any heat source and keep all batts away from chimneys

  3. Do not install insulation batts over wiring, where possible lift the wires and slide the batt under them or tear the batt in around the wire.

  4. Make sure you put a batt over the manhole cover and do any in ceiling walls and attached garages

  5. Follow the safety recommendations for walking in a roof, 3 points of contact at all times etc....

  6. Watch out for danger, if you get cramps or taste blood in your mouth you need to hop out, cool down and rest

Cleaning up and getting the itchy out of installing insulation batts?


You will be itchy if you install fibreglass batts, just how itchy depends on the person. If you are so itchy that you want to scratch your eyeballs out these suggestions might help.

  1. Wash with cold soapy water - I never do this but I have been told that a hot shower opens your skin pours and causes the glass to get in deeper but a cold shower closes the pours and pushes the glass out. I am not sure but a cold shower might be good it you are really hot still.

  2. Take a couple of pain killers

  3. For a really bad itch, rub baby oil on your skin (Rub it in good) and then have a hot soapy shower to wash it off again. This one really works and is my go to solution if I have a fibreglass itch.

I have been told that some people itch for as much as 5 days, for me it gets less and less for about 3 days normally unless I use the baby oil trick because that knocks it down by about 90% on the first night.


If all this sounds hard it is because it is very hard. As hard as you think it is, it is a lot harder !! I have had grown men in tears trying to keep up with me on their first day working with me ... it is that hard. I describe the job to new staff as running on a treadmill in the dark while in a sauna, with people hitting you in the sides with baseball batts.

The other point is after you have done all this work, you will have a cheap crappy batt insulation in your roof that will be prone to rats and mice living in it and will most likely need replacing in 10 years time. Why bother, Just get a quality Cellulose fibre insulation installed in your roof.


How long should installing Roof insulation Batts in my roof take ?

Well with my trained teams, I estimate about 1 hour to 1.5 hours per 100 square meters of batts that need to be laid. That is my total site time from when we drive up to when we leave. Now to be honest it is hard to find installers who want to work that fast but that is what a good team will do all day every day. The truth is that most big batt companies only pay about $1.5 per square meter for subcontract batt installation and so if they are not able to do it at this speed, they will be loosing money. That is why batt installers very often cut corners and do doggy jobs.

For a DIY person who follows my instructions above for tossing the batts and tearing them instead of trying to cut them. I would expect it to take them 3 hours for every 100 square meters with two people working in the roof.

For a DIY person who is not following my instructions, I expect them to take 5 hours per 100 square meter and they will probably give up in fact.


Hot tip bonus for installing Insulation batts

  1. Tear batts do not try to cut them, it is dangerous to work with a knife in the roof and batts do not cut very well. Polyester batts do not cut at all and they only tear in one direction, across the width of the batt.

  2. If you have bays that are 430mm wide but you only have 580mm batts or vice a versa. From the middle of the roof, where you have room to work, tear enough of the batts to the right size needed and toss them into the offending bay. It is much easier than being in the edge of a roof trying to tear batts to size.

  3. Laying down in the roof is ok and in tight places it may be helpful to use your foot to push batts into a small area (because legs are longer than arms). Just make sure your hip is always sitting on a joist and never rest anything on the plaster.


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