By Roger Greene, project manager at www.northlondonloft-conversions.co.uk
If you’re happy to do your own home improvements and you can use a staple gun, then you’ll be able to install a green energy barrier to keep your home cool in summer and warm in winter. In fact it is such a simple process, you may be forgiven for wondering why you didn’t do it yourself years ago.
Most people have ordinary insulation installed in their roof attics. That’s the stuff that’s made from fiberglass or cellulose. But get this clear right before you start; radiant barriers are not intended to replace regular insulation. They help to reduce radiant heat loss or gain specifically – they don’t reduce conductive heat efficiently. But by reducing radiant heat, they make traditional insulation much more effective.
If you are building a new home, invest a couple of thousand more in insulation, radiant barrier attic insulation.
Why Don’t builders Install Radiant Barriers?
What am I talking about? Radiant barriers. They install in attic spaces and reduce radiant heat transfer by up to 97%. Reducing energy bills up to 40%.
Radiant barriers are made from aluminium, and you need a good quality material that is double-sided, durable and strong. It shouldn’t tear when you start cutting around vents. Also, you always want to use a perforated product that breaths to keep from trapping moisture.
So, step number one is to work out how much material you need. If you can’t do the math your dealer will help you. The only tools you need are a staple gun and a standard utility knife for cutting.
Then go home and simply staple your radiant barrier up to the bottom of the rafters. This is the preferred method in hot climates. In colder climates, you can lay the foil directly over the attic insulation. It is not a complicated process, so don’t complicate it by over thinking it. Remember that for a radiant barrier to be effective, it doesn’t have to look pretty. It really doesn’t matter what the radiant barrier looks like, if you get the foil between the roof and the insulation it is going to work.
Okay, so now you’re in the attic – hopefully on a nice, cool day. Start working from the bottom. If the wall that is parallel to your rafters is 40 feet, that’s how long the first run must be. Leave a small space between the floor and the edge of the foil – this will allow fresh cool air to flow up behind the radiant barrier. Then staple three to four times into every second rafter. You can staple into every one if you like, or every third one, depending on the spacing of the timbers.
It takes the pros about five minutes to staple-up a 40 foot run. Their motto is to “cover as much as you can, as fast as you can”.
When you reach vent pipes, simply cut around them. Make the cut about six inches bigger around any combustible pipes, like hot water heaters.
When the first run is in place, start on the second, overlapping the foil by about two inches. When you get to cross supports you’ll have to wrap the foil around them. If you use the truss as a cutting board, it’s a quick and easy process. Cut a T in the foil and wrap. Remember it isn’t supposed to be airtight because foil is like shade … it has a cumulative effect.
Run the foil all the way up and leave a 3-6 inch space at the top. Hot air will rise and leave the attic through this gap. This method will significantly reduce heat gain into your home.