Thermal Insulation of Roofs


#1

hi brothers,

does any one of you has ever installed thermal insulation on roofs?

i am looking for a solution that would fit on the existing roof (not ceiling) without disturbing the utility of roof.

what is going to be the investment for insulating a roof for a typical 12 Marla house?

is there going to be any real saving in terms of energy bills or it is just a hoax sort of thing?

thanking you all in anticipation.


#2

Insulation is never a hoax. In Pakistan they find it more economical though to only insulate the roof as most of the heat gain in summer is through the roof. I mean look at your fridgerator.. Turn it off and the stuff inside stays cold for a long time thats because its insulated. Insulation keeps heat from entering into our house which means its naturally cooler, your airconditioners dont have to work as much so less electricity bill... you wont need such a huge tonage, IE if you currently use a 1.5 ton ac in a room, with good insulation you could easily downgrade to a 1 ton and save money there too.

Anyway I'm also curious as to the cost as my house has already been constructed but want to insulate now without using utility of the room and I figured foam insulation is the best, but then you have to reseal your roof again with cement or watever so that is costly. Anyone can explain?


#3

I've heard about Diamond's Jumbolon but it is very costly, about Rs. 50/- per sq. ft. means more than 1 lac for a house of 12 Marlas.

Some ceramic type tiles are also there but their thermal insulation would be lesser than Jumbolon.


#4

Actually I heard from the company that it is around Rs.20/ per sq. foot for one inch thick insulation and they said that was good enough for islamabad so for a one kanal house like mine considering the roof is 2000 sq foot, thats only Rs.40,000/ but the only problem is my house is already constructed so it would cost around Rs.60,000 more to re-cement over it again. I still think the energy savings and comfort level would be worth it though, both summer and winter. I'm just curious though since its already constructed house which would be best, the foam or the spray?


#5

Clay tiles with the appropriate mud works best. They reduce the temperature at the peak by 3 to 5 degrees, which is pretty significant. Also ensures that your A/C doesn't have to work as hard either. Might cost a bit more than foam, but it's long lasting and doesn't leave your roof unusable.

Good luck!


#6

it would take 4 feet of mud to equal the amount of insulation that 1 inch of foam could give you... minus adding all that weight to your roof...


#7

[quote=", post:, topic:"]

Clay tiles with the appropriate mud works best. They reduce the temperature at the peak by 3 to 5 degrees, which is pretty significant. Also ensures that your A/C doesn’t have to work as hard either. Might cost a bit more than foam, but it’s long lasting and doesn’t leave your roof unusable.

Good luck!

[/quote]

Can you recommend how that can be done in Karachi? Any recommendations for who can do it and an average cost?


#8

@yotoy

That's why you use a few inches of mud topped with baked clay tiles which reflect heat as opposed to absorbing it. It has the same effect without incurring the additional load on the structural components of the building. I believe every now and then you are supposed to water down the tiles, but I'm not sure.

@isharis

Not sure where, my gardener arranged it. I think the tiles came from Bohra Pir.


#9

[quote=", post:, topic:"]

Clay tiles with the appropriate mud works best. They reduce the temperature at the peak by 3 to 5 degrees, which is pretty significant. Also ensures that your A/C doesn’t have to work as hard either. Might cost a bit more than foam, but it’s long lasting and doesn’t leave your roof unusable.

Good luck!

[/quote]

can you post some pic how it looks like? and estimate per square foot price? and i m not able to get how could you walk on mud topped clay tiles installed on your roof (as you said it doesnt kill the utility of the roof )


#10

there must be some hi tech way to have thermal sealing of roofs.

monsoons are coming and i don't want to do such an experiment that will end up on seepages.

someone told me about spray polyurethane thing. have u ever heard anything about that? is that solution accustomed to industrial users only?


#11

Thermal insulation is not the same as roof waterproofing, do not make the mistake of confusing the two. As far as pics of my roof, I'll take them when I get the chance.


#12

We recently got spray polyurethane (PU) treatment for our house in Islamabad. The results are dramatic.

I know of at least three firms that provide spray PU services in Pakistan. One operates exclusively in Karachi/Hyderabad and with their add appearing regularly in the daily DAWN. The other two are Master Chemicals (manufacturers of Moltyfoam) and Diamond Industries (manufacturers of Diamond foam). They offer this service in Punjab and N.W.F.P also and their contact info for Rwp/Isb is as follows:

Master Chemicals (Pvt.) Ltd.

Islamabad.

Tel: 051-2279816, 051-2271175

Fax: 051-2271175

http://www.masterchemical.com.pk/poly.html

Diamond Jumbolon

Tel: (051) 111-111-666

Cell: (0333) 5600393

http://www.jumbolon.com/spray_description.htm

There may be others but I am not aware of them.

Basically the process consists of two liquid chemicals that are kept separate till the last moment before spraying their mixture at a pressure of 110 psi. The chemicals immediately react and the semisolid goo turns solid within 10-15 seconds. The resulting compound sticks to anything and also flows into and fill all the cracks (thereby helping to water proof the roof as an added benefit). They said the treatment has no life limit and should last the lifetime of the building. However, it is degraded by the UV radiation of the sun and needs protection from that. Therefore it needs to be covered up by either concrete screeding (for regular foot traffic) or a special UV paint or an elastomeric coating (for minimal foot traffic). Both can be arranged by the same people who do the spray PU treatment. In our case we went for Master ThermoShield. It cost Rs. 32/sq ft for the basic spray PU and a further Rs. 17/Sq ft for the elastomeric coating. The UV paint option was available for Rs. 12/sq ft though.

One more thing and I got this from Master (so may include business prejudice). They said only they use German material (BASF) while Diamond uses Chinese material (ICI China).

The spray PU treatment may not be an option for those living in rented accommodation. In such a case, just paint the top of your roof a bright white. This will reflect the radiant energy of the sun away. However simple this may sound, believe me it’s extremely effective. The only down side is the relatively short life requiring repainting more frequently. You can use from plain simple limestone (dirt cheap but gone with the first shower) to limestone+POP (more durable but messy) to paint (plastic emulsion will cost Rs. 8-10/sq ft but will stay on for a couple of years). Results are dramatic nonetheless.

Finally a word for those building their house. At the first opportunity, plant saplings of tall growing trees on the south side because that is where the sun will always cast it's shine during summer (applies to northern hemisphere only). Also consider PU injection of your outer walls in addition to spray for roof. Treating the walls require hollow wall construction whereby the outer walls are constructed as double walls leaving a one inch gap in between. The PU is then pressure injected into the cavity through a hole that is later sealed off with concrete. PU treatment during construction is not only cheaper but wall treatment will keep you warmer in winters too and help reduce your energy costs/carbon footprint.


#13

excellent reply taru exactly what I wanted to hear, hope others as well


#14

Promising

Master's Solution sounds flexible and durable.

What do you think if concrete screeding will allow enough foot traffic or i would have to opt for roof tiles?

What is going to be the final cost per square feet?

Moreover, i wonder if white paint is going to do the job? Is that going to stand guard against invisible light which constitutes a major chunk of the irradiated heat of the sun?


#15

[quote=", post:, topic:"]

…i wonder if white paint is going to do the job? Is that going to stand guard against invisible light which constitutes a major chunk of the irradiated heat of the sun?
[/quote]

You may find these interesting:

http://en.wikipedia.org/wiki/Cool_roof

http://blogs.chron.com/sciguy/archives/2005/12/should_you_pain.html

http://commentisfree.guardian.co.uk/bjrn_lomborg/2007/11/paint_it_white.html

http://www.redorbit.com/news/science/968210/white_is_the_new_green/index.html

Happy painting!


#16

I hereby nominate Taru's post as the best written, most informative post of the year.

Cheers


#17

any idea on how much expect to pay for concrete seeding per foot?


#18

what they mix in the paint that is used on roads? it lasts quite long in such harsh conditions


#19

i wonder if the 1 inch concrete screeding will overburden the roofs to be insulated in this case.

am i right?


#20

[quote=", post:, topic:"]

is there going to be any real saving in terms of energy bills or it is just a hoax sort of thing?

.

[/quote]

I dont understand, how would this save energy bills ?