FREE Shipping on orders over $600

Radiant Barrier

Radiant barriers are also know a reflective insulation that reflects the transfer of heat by the way of thermal radiation. Radiant barriers do not perform in the same way in which standard glasswool or mineral wool batt insulation would work. Instead the radiant barrier will use its reflective surface to reflect radiant heat, this works when you have a cold surface on one side and a warm surface on the other side. A radiant barrier generally does not carry an r-value as its resisting heat or restricting heat flow it reflects radiant heat. Radiant barriers will perform equally well in hot and cold climates.

As radiant barriers reflect radiant heat and do not carry an r-value they can also be called up as thermal / heat insulation.


Radiant barrier in your roof;

So what happens when you put a radiant barrier into your roof. Well first of all if you do not use a radiant barrier in your roof space what will happen is your shingles will get very hot on the outside from the beating sun which will in turn warm up the underside of the shingles. This will in turn heat up the osb underneath which will also inturn heat up the underroof side of the osb thus heating up the attic space. By installing the reflective radiant barrier it will reflect this heat outwards thus keeping the inside room temperature at a comfortable level.

It is also possible to use a white shingle tile or a reflective tile on your roof which will perform quite well to reflect the heat outwards but will not perform as well as a radiant barrier will and also a white shingle or reflective roof is not always aesthetically pleasing to the eye.

Radiant barrier can also be applied to insulation during the manufacturing process you will notice some companies such like Owens Corning / CertainTeed / Johns Manville etc all fabricate a foil faced glasswool insulation. Other insulation types like Polyisocyanurate insulation (Polyiso / PIR) also have a foil face and again this is purely as a reflective barrier and will act similarly to radiant barriers.


Radiant barrier in your attic;

The most common application here is laying the radiant barrier over the glasswool or mineral wool insulation. However there are some precautions to take as per the Reflective Insulation Manufacturers Association International whereby they advise that perforations be installed into the reflective insulation to allow for the movement of air and vapours that may get trapped between the reflective insulation and the ceiling. This could over time cause mould build up on the underside of the reflective insulation or the glasswool / mineral wool insulation. Perforations the size of at least 5 perms are recommended here. Another downside to this application is the buildup of dust over the reflective foil on the up side. This will over time decrease the radiant barriers performance, so maybe best to set your alarm for once every 6 months to go up and wipe off all that dust.

Another application for the radiant barrier in your attic could be to the underside of your rafters. A simple staple gun and some elbow grease will get the job done in no time by stapling the radiant barrier to the rafters. This is a quick and easy fix for your attic and will be very effective at reducing your heat lose and reflecting your heat back into your home.


Radiant barrier in your Walls;

Again much like with your attic it is recommended that your radiant barrier can breath here to avoid any buildup of high moisture content air within the cavity space behind the radiant barrier. Again the radiant barrier can be stapled to the stud framing at whatever centers the stud framing is at. Again just make sure there is plenty of space for the movement of air and nothing will get trapped in behind that wall.

If you wish to use a radiant barrier on your external wall then again you can vent the cavity with a breeze block or wall vents can be used to allow for the circulation of air from bottom to top. This is vital to get right so make sure when the job is finished that nothing has fallen in behind the vents or anything is blocking the airflow through them.


Radiant barrier in your Floors, Crawlspaces and Basements;

Radiant barriers work very well for floors and crawlspaces especially when underfloor heating systems are deployed. The radiant barrier will prevent the warmth from passing through to the crawlspace or basement. Just like the walls and roof applications the radiant barrier can be stapled to the underside of the floor joists again at whatever centers the floor is already at. In this situation however where a crawlspace is under the floor it is not a good idea to perforate the radiant barrier as the moisture from underneath will pass through the barrier into the underfloor void and into the living space of the home. So the radiant barrier will act as a vapour barrier also.

Back to top