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TRULY insulate your loft (or attic!) - and save the planet

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Being time rich and money poor, I wanted to cut my outgoings, and be a bit greener.

So I fixed SF40 SuperFOIL to the underside of my rafters to keep warm, cut bills and save the planet: www.superfoil.co.uk/SF40-titlepage.html

I chose SF40 because:

a) It nails to the roof, so you can still use the loft for storage
b) It has a radiant heat barrier
c) It is the equivalent of fitting 450mm (18 inches) depth of fibreglass*
d) It should keep us cool in summer too

I expect there are other products you could use, but this one seemed right for us.

There are a lot of steps to this instructable, but it's not as complex as all that. I waste a lot of time talking about nailguns and such. You can skip to step 16 if you want.

NB: Apparently what we Brits call a loft is what our Yankee cousins call an attic. For them this 'ible is about attics.

* Clarification: fibreglass does not block radiant heat; the quilt does. In order to get the same savings, you would have to install 18" of fibreglass. But this does NOT mean that the R values are the same. See the manufacturer's brochure illustrated in the second pic of step 3.

 
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Ohnanka7 months ago
I wanted to insulate the roof in my attic as it has been floored and adding further insulation to the ceiling of the top floor would be tricky.
However, it seems like my roof has no felt under the tiles! Do you think I am going to have to replace my whole roof before insulating?!
LDW (author)  Ohnanka7 months ago
> I wanted to insulate the roof in my attic as it has been floored and adding
> further insulation to the ceiling of the top floor would be tricky.

Exactly my own situation.

> However, it seems like my roof has no felt under the tiles! Do you think I am
> going to have to replace my whole roof before insulating?!

Well, I'm no expert, and I don't know what your local conditions are. Quite a lot of older properties have no felt, just as yours does. They've been OK for years, so it can't be such a big problem.

If I were in your shoes I'd want felt under my tiles, but you don't really need to do this until you reroof. In some conditions it is possible, I believe, to lift off the tiles in sections, felt, and then replace.

So I don't think you should replace the roof just to put in felt; if and when the roof needs re-doing, then put felt in at that point.

Meantime, I can't see any reason why you shouldn't put in quilting below the rafters as I have done, leaving the unfelted roof in place. But you ought to consult an expert.

Hope that helps a bit.
LDW (author)  LDW7 months ago
PS - Why don't you contact Superfoil www.superfoil.co.uk and ask them? If anyone knows, they should.
This is a great idea, especially with our energy conscious society now. Just to clarify though, this shouldn't be done on the roof of ATTIC though with the blown (or bat) insulation on the floor, right? Only for a LOFT? I am a air conditioning repair man, and doing this in an attic seems like a super bad idea.
LDW (author)  casperboost1 year ago
Attic = loft = attic. Same thing.

> doing this in an attic seems like a super bad idea

Presumably because you're locked into the COLD ATTIC principle. Like so many repair men. And you've probably got some cockeyed ideas about condensation.

Go back to square one. The idea is to stop heat going out of the roof, da? So nothing that does that is bad, nyet?

Read up on the WARM ATTIC alternative. Keep the heat in the house. Yes, insulate the floor of the loft/attic. But also stop the heat leaving the attic for the sky by insulating the roof - especially, as in my case, where the loft/attic is used for storage. Plus conventional insulation does nothing whatever about radiant heat, so you're saving there too.

Also benefit from cooler summers. Actually, it's all here if you read it.

kwazai1 year ago
you could add a perferoated pipe at the ridge to collect solar heat in the winter- I've seen pool heaters use this. One of the sites even had the calcs to determine if it was adequate to heat the swimming pool. The offgassing of the underside of the roof probably would not be good to breathe so a water based heat transfer would be needed to keep it breathable hot air if wanted.
No heat escape from your roof up here in northern Canada can be an extremely bad thing... I have an extremely well insulated roof that requires shoveling every winter - to explain: My house was an old, log, summer cabin that was winterized and now has another insulated, tin roof over top of the original. You would think that a tin roof would be throwing the snow off on it's own, but no such luck. There is absolutely no heat escape so the snow just piles up. Come mid winter my doors start closing a little less square and things start to creak a lot more than usual. Not to be a pessimist though. Still a great instructable :)
Ever consider using some of that "anti-ice-dam" wire, possibly across the whole of your roof? Tin should be especially good at picking up the heat from the wires and warming enough under the snow to cause a liquid layer to form immediately above the roof, facilitating an avalanche.
LDW (author)  No_Where_Fast4 years ago
That's good - the snow acts as another insulating layer... :-)
_soapy_ LDW4 years ago
If the weight of the snow didn't crush the house, then yes, it would be great! As it is, I'm sure he doesn't want a warm coffin.
LDW (author)  _soapy_4 years ago
:-)
rattle093 years ago
I do not recommend anyone do this to a roof covered with asphalt shingles. There must be an airspace between the underside of the roof sheathing that is clear to the ridge of the roof. At which, there must be some type of ridge vent. Without these the summer sun and heat will literally bake your roof and with in a short couple years the shingles will curl up and be ruined. Your shingle warranty will also be void.
tcup rattle093 years ago
Ah, good tip. How then, does one safely insulate their roof? I have a ridge vent at the peak of my roof. My roof developes huge icecicles during the winter.
Mike44 tcup3 years ago
Yeah, as rattle09 said, you probably don't have continuous airflow from your soffit up to your ridge vent. Look up pictures for attic venting - there's some on the Pink Panther insulation site: http://insulation.owenscorning.com/homeowners/

You may have a situation something like this with no air flow: http://www.nylumber.com/images/ice2.JPG

What you want to do is add those styrofoam spacers (raft-r-mate polystyrene attic rafter vents): http://roofing.owenscorning.com/homeowner/accessories/ventilation/raftrmate.aspx
tcup Mike443 years ago
Thanks guys for your advice. The only insulation in my attic is on the floor. I never heard of rafter vents. I'll have to look into them. I'll be doing that job myself so I will have to buy everything peacemeal as I can afford it. Meanwhile I'll be adding calcium chloride to the areas of my roof, that I can reach. I saw something that says to fill knee high panty hose with calcium chloride then lay them on the edge of your roof, that will prevent ice from forming. This will be interesting, I hate hights.
One thing you can do with the panty-hose is to tie a long rope to one end, and just throw them up onto your roof while letting the rope dangle to the ground. This way, you can retrieve and re-throw the package until you get the position right, and also pull it down to refill it or put away in spring. Voila! No roof-climbing required.
Last winter, I tried the calcium chloride in the knee high panty hose thing. It worked. Unfortunately, my house had the look of a bordello with all those panty hose all along the roof edge.lol. Then after winter was over, there were black stockings all over the yard, somewhat embarrassing. But the main thing is that the method worked, I had some icicles but not as much as previous.

You can also get wiring kits that have you tack a warming wire in an up-and-down curving pattern on the overhanging portion of your roof. You can then plug this wire when you notice ice starting to form, and melt tracks through the ice dam to allow the accumulating water that can back-up under your shingles and into your attic to flow off the roof. It's a longer-term fix, because you can just leave it up year-round and use it as necessary.
rattle09 tcup3 years ago
There is a styrofoam product made that is designed to fit between the rafters. Its concave shape allows an area of ventilation from the lower roof edge to the ridge vent. You would install these prior to the process that is described here in this instructable. This will allow the heat to escape from below the roofing therefore helping keep it cooler.
LDW (author)  tcup3 years ago
Well I don't have rattle09's knowledge of asphalt shingles, but AFAIK you should be safe if you fix the quilt to the underside of the rafters - in which case there will be a gap the same depth as the rafters between the roofing material and the quilt.

Best check with the manufacturers. Someone here has recommended:

www.eshield.net

and they look OK to me.
LDW (author)  rattle093 years ago
There must ALWAYS be an airspace between the quilt and the roofing material. That's why it's fixed to the underside of the rafters - although it can be used in certain new builds immediately below the roofing material - see www.ecofoil.com/Applications/Roof-Insulation.
surfrescue3 years ago
I just had this done in teh USA covered a 2500 square foot house took about 3000 square foot of material. (i have a single story downstairs beddroom that added a lot of loft area hence the large amount of material.

I used Esheild, and they Garentie a 25% savings in both your electic and gas bills ove they year i ended up paying 4300 dollars USA but we do get a 1500 Dollar tax rebate for doing it. so the cost looks like 2800 Dollars including installation. they also wrapped my hot water tank with the stuff to which is supposed to help reduce heat loss from the tank in the same way

my energy bill comes in at around $3200 a year (yes you brits be darned glad you dont have to pay for AC !! im from britain originally and AC running costs are crippiling) so my return on investment is $800 a year so total cost of the project paying for itself is 3 and a half years in theory... and thats without indexing inflation of energy prices.

time will tell if the energy saving is 25% the company also gave me energy saving bulbs etc, but i already had them throught the house and also have a full programable thermast that i have set to VERY conservative settings
LDW (author)  surfrescue3 years ago
PS:

I meant to say, the reason you will save on aircon - we hope - is that i n summer, up to 93% of heat gain is radiant. No amount of fibreglass or lambswool or any other kind of insulation will help with that. But the quilt is a radiant heat barrier.

Stay frosty!

Parabola949 LDW3 years ago
Ahh thank you. That was the response I was looking for. I live in Texas.... you know, where it stays +100 F for more than a month straight. I Just bought my first house, and of course, my first thought is... insulate. Especially considering the house was built in '73. First thing I did was go up to the attic (loft if you will)... yipes. Nothing roofside of course, just bare wood | shingles on other side. Bottom covered in wool / fiberglass, and spotty at that. I knew right away it wasn't going to do. In fact... one day it was 72 outside, 76 inside. Obviously I also have an AC problem...
But still, it heats up within half an hour of the sun coming up. This old house obviously needs an insulation make over.

In fact, one day (after leaving the AC off all night, allowing it to thaw from freezing up), we kicked on the AC just before sunrise... still got to 90 F inside....

I have a lot of work to do.. just need to get through christmas first (5 kids = no extra cash)

Thank you so much for this instructable. I will definitely give it a go
I live in Oklahoma and I feel your pain! When our HVAC crapped out, we replaced it with a geothemal system. WOW -- it makes a difference. I wouldn't have just said "hey, let's go out and buy this", but when we were looking at the cost of the whole system (heat AND a/c), and the efficiency ratings, we decided to go for it. The initial outlay was pricey, but it's already started to pay for itself.

For places that have such a big temperature swing (110F on a hot day and 20F on a cold day), or for the months of April and October when you have both the heat and AC on in the same 24 hour period, great insulation and smart appliances are pretty much mandatory for survival.

Pay close attention to your windows, too -- they're basically huge holes of inefficiency and waste.
LDW (author)  Parabola9493 years ago
If summer overheating is your problem, you are going to LOVE this.

Check out this:

www.ecofoil.com/EcoFoil-FAQs-Radiant-Barrier-Reflective-Foil-Insulation
5 kids = free insulation installer labor :)
Hah except I got one of those attics that you fall through if you step off the beams...lol
tcup surfrescue3 years ago
Where, in the US, is this available?
LDW (author)  surfrescue3 years ago
Great!

I think you'll find you save on AC too: the quilt should keep your house cooler. It certainly works here in UK on the one day a year when we are too hot!     :-)

Thanks VERY much for posting: let us know how you get on with the bills.
h3idi3 years ago
I love that they warn you of the glare if using outside. Safety first! ;)
Mike443 years ago
This is a great idea, especially with our energy conscious society now. Just to clarify though, this shouldn't be done on the roof of ATTIC though with the blown (or bat) insulation on the floor, right? Only for a LOFT?
LDW (author)  Mike443 years ago
Erm... sorry Mike444 - I don't think I know the difference between an attic and a loft. AFAIK they're the same thing. What did you mean?
mephit LDW3 years ago
I think we've run into a bit of a language issue. I'm guessing that Mike44 is a fellow American and therefore confused by your use of the word loft. In the US, loft can often mean just the upper habitable storey of a building or even just large, open living spaces usually converted from commercial property and often having very high ceilings (i.e., they're "lofty"), whereas the attic is the area just under the roof often used for storage. This means you can actually have an attic over a loft. Confusing, I know. In answer to Mike44's question, though, this is being done to what we here in the States would call an attic. In this case, a floor has been planked in on top of the insulation covering the joists of the attic making it appear to be a more finished space than many Americans are used to seeing in their attics.
LDW (author)  mephit3 years ago
Ah - thank you, mephit. Tricky animal that English language...

You are in the right of it: my attic (we use that word interchangeably) has floorboards in it - as explained in step 5.

The title of my 'ible has been amended accordingly.
mephit LDW3 years ago
As that wit Shaw said, we are "two people separated by a common language." I have found it handy on more than one occasion to be an American with a large number of UK relatives.
Mike44 mephit3 years ago
Ha true true, well, not quite American....I'm Canadian, but us North American's probably use a little bit different lingo than what you use 'across the pond' :)

Attic: mainly an UNLIVABLE space at the top of your house; has roof trusses throughout the support the roof, so you can't really put a 'livable' space up there; insulation along FLOOR of attic keeps building heat inside (http://www.arrow-insulation.com/img/photos/beforeandafter/large/attic_insulation_after_3.jpg)

Loft: a LIVABLE space where the roof trusses are placed more off to the side in such a way to provide a livable space in between; the insulation is placed along the ROOF/WALLS of the loft; thus there may be no true 'attic' space above (http://i37.tinypic.com/ax1da1.jpg)

I guess my question was just getting to the idea that by installing this on the roof of an ATTIC which already has insulation on the floor would kind of be defeating the blown in floor insulation. Then the heat would be trapped within the metal blanket and blown in insulation, leading to problems.

Also, yes, it's absolutely critical to maintain an airspace between the roof proper (like the plywood) and insulation from the soffit at the bottom of the roof up to the space where the ridge vent is:

http://www.inspectapedia.com/BestPractices/Figure2-57s.jpg
http://www.nachi.org/images10/ridge-vent-baffles.jpg
http://education.nachi.org/images/upload/soffit-ridge_vent.jpg
mephit Mike443 years ago
Ah! excuse me for the incorrect assumption, then. I imagine ya'll get tired of being mistaken for us. :D

I'm not a contractor or roofer or insulation specialist or anything, so please excuse me if I say something stupid, but aren't you assuming there's a ridge and soffit vent system? Not every building has them. I know my house doesn't have either. It's got an old-style rotary attic vent, but no soffit vents. My house was built between 1946 and 1949. There are plenty of other buildings around of a similar age that might not have a modern vent setup. Would they still need the airgap between the roof decking and the insulation?
Mike44 mephit3 years ago
Oops, yes, sorry, I should have clarified! :) I'm assuming a more 'recent' house. With an older house like yours though, you probably don't have to be as concerned to get this airflow going because they were built "less airtight" back then when compared to today's houses (vapour barrior, polyseal, acoutiseal, etc. the works nowadays!). There will probably be some natural airflow somewhere there! Oh, and I do believe that those revolving roof vents are (*I think*) about equivalent to the ridge vent. At least that's what I've been told!! Don't quote me though :) Seems logical though. With that being said though, they are much less airtight, so you may experience heat loss through the attic. Do you get any icicles forming on your roof at all?
mephit Mike443 years ago
Don't know yet. I only bought the house in May of this year and I live in the Southeastern US. We're currently having a cold-snap, so I'll keep an eye on it, but I seriously doubt they'll form. My house has nothing but the original inch or so of insulation in the attic floor and no roof insulation of any kind. The heating system seems to mostly be heating the attic and not much the rest of the house. The roommate currently living in the attic room says it gets surprisingly hot up there while our downstairs area is still pretty chilly. I'm wasting dollars and energy I'd rather not waste, so that's one of the reasons I'm interested in this 'ible. Unfortunately, the entire attic space has been thoroughly and very cleanly floored with the inadequate insulation between the ceiling below and the floor above. Factor in the additional fact that more than half of the attic space has been converted into a room (just under the ridgeline, of course!) and it basically means I'd have to gut my attic to re-insulate it. Whee......
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