Deflect solar heat by appling white paint to the underside of roof in attic?
Question:
Answer:
Probably not worth the trouble. The radiant heat absorbed by the roofing material is simply to great to be offset by white paint. I've actually seen aluminum foil used in the same attempt. Basically all paint or foil will do is reflect back heat already stored in the attic space. Invest your money in attic ventilation...turbines or thermostatically controlled fans. Make sure you have plenty of insulation with the vapor barrier directed towards the living space (this should tell you something about your idea) and ventilated.
YOU NEED TO REMOVE THE HEAT. TRY A SOLAR ATTIC FAN. THE FAN AND SOLAR PANEL COMES AS A KIT PRICE IS AROUND 300DOLLARS. IAM IN THE MIDDLE OF REHABING A HOUSE THAT IS 100 YEARS OLD AND PLAN TO INCORPERATE SOME SOLAR TO HELP KEEP COST DOWN.U MAY E-MAIL ME AT bakerstreet_pa@yahoo.com.
Unlikely to have much effect, but you are on the right path.
According to tests done at the DOE/Oak Ridge National Lab & Univeristy of Central Florida/ Florida Solar Energy Center the most effective radiant barrier was actually over the ceiling joists, NOT directly against the rafters.
The radiant barriers they tested were sheets of mylar foil, far more reflective than any white paint good ever be.
I think the priority is #1 -- INSULATE the space as much as possible #2 -- VENTILATE the space #3 -- SEAL any air leaks #4 -- Use a REFLECTIVE BARRIER
http://www.ornl.gov/sci/roofs+walls/radi...
Here is the energy saving sheathing my son had installed on his new house which will give you an idea of other options besides paint. How about using a contact type cement to glue aluminum foil to the underside of the roof sheathing between the roof rafters? They may even have a stick on foil designed for that purpose now.
http://www.lpcorp.com/lpstructuralproduc...
More Questions & Answers...