Ed and Fran
Aug 24, 2006, 3:08 PM
Post #1 of 9
We have a fairly standard 10cm (4") concrete slab roof (slight slope). Because it is exposed all day to the sun, it gets pretty toasty upstairs. The a/c is hard pressed to keep up. I wonder if there is anything worthwhile that I can do to retrofit insulation to this existing roof? I have 3 possible thoughts, and would appreciate either comments on these ideas, or any other techniques that you know about.
1. Painting the roof with one of those combination waterproofing/thermal insulation paints, probably in white. Easiest, but I wonder how much help this type of product actually provides. (Note: don't need waterproofing, but I've usually seen this type of product as the combination.)
2. Installing spanish tiles (either the real ones, or those new panel type products) over the existing roof. If I leave the spaces under the curved tiles open, I wondered if the combination of shade and air movement under the tiles would help knock down the temperature in the concrete slab.
3. Put a thin layer (maybe 2") of styrofoam insulation on the roof and pour maybe 2" of lightweight concrete on top to hold it in place.
I suppose I could also consider installing a suspended ceiling inside to help insulate from the radiant heat from the slab, but that wouldn't be my preferred option if I can avoid it.
If I were starting from scratch, I'd install one of those roofs that use the large styrofoam blocks on the formwork to produce a honeycomb slab. But we're not going to rip the roof off and do that. By the way, that style of roof slab has its own name down here, but I'm not sure of what it is. I believe it's something like "losa reticular". Anyone know for sure?