Joisties | Steel Underfloor Insulation | FAQ

Q: What are Joisties made of?
A: Joisties are made of polyester fibres compressed into a firm board. 

Q: What R-Value are Joisties?
A: Joisties provide the standard thermal break for steel building elements of approximately R0.2

Q: Why do I need insulation as well as Joisties?
A: Joisties insulate the steel joists and hold the insulation in place. Joisties do not insulate your floor, they only insulate the joists themselves. You will still need bulk insulation to put between the joists. 

Q: How do I install Joisties?
A: Click the How To tab to watch the installation videos

Q: What’s so special about the Joistie adhesive?
A: The Joistie adhesive has two very important qualities. Firstly, it’s low VOC. This makes it safe to use even in low ventilation spaces. Secondly, it has a very high “grab” so that means that once you stick the Joistie up, it will stay up. That makes it easy to get the job done.

Q: Can I use Liquid Nails instead of your more expensive adhesive?
A: Yes you can but we don’t recommend it. It will be much messier and take much longer.  Liquid nails will not hold up a Joistie straight out of the cartridge. You will need to undertake the “contact adhesive method”. That is, apply the adhesive to the Joistie, stick it up, take it down, allow the adhesive to go tack free, (5 to 10 minutes) and then re-stick the Joistie up.  Also, Liquid Nails is high VOC so is not safe in a low ventilation space.

Q: Must I use your Joistie fitting tools?
A: No, you can fit Joisties without the fitting tools. Aligning the Joisties along the joists so that they support the insulation on both sides of the joist will be much harder without the tools, but it can be done.

Q: How long does it take for the Joistie adhesive to set?
A: We recommend you leave it at least 24 hours before fitting the polyester underfloor rolls.

Q: How can I trim Joisties to length or to go around pipes and wires?
A: Joisties are easily cut with a sharp utility knife. When trimming to length, use another Joistie lapped over the one you are trimming. This will provide you a square guide to trim by.  Rebates are also easily cut using a knife.

Q: How many Joisties are in a box?
A: Each box contains 20 Joisties. Each Joistie is 1m long so one box will cover 20 lineal metres of joists.

Q: How can I work out how many Joisties I will need?
A: Each Joistie is 1m in length. Measure the length of the joists and multiply by the number of joists to get the total lineal metres required. There will likely be sections of your floor with different length joists. It’s a good idea to make a sketch and write on your drawing the length and count of joists in each section of floor.

Q: How do I know how much adhesive I will need?
A: One cartridge of adhesive is enough for about 30 Joisties if you follow the recommended pattern of adhesive. It’s prudent to order an extra tube just in case you over apply adhesive.

Q: Are the powerful magnets on the fitting tools safe?
A: Under normal circumstances the magnets are safe. If you have a pacemaker or other bodily electronics or artificial joints it’s best to check with your medical professional first.