I have solid precast poured concrete garage with a flat roof. The problem is, by 3pm that this has heated up and starts baking like an oven. What would be the cheapest way to insulate it? Has anyone else ever dealt with something like this?
I have solid precast poured concrete garage with a flat roof. The problem is, by 3pm that this has heated up and starts baking like an oven. What would be the cheapest way to insulate it? Has anyone else ever dealt with something like this?
Is it already painted white? If that doesn't work you're looking at building something that creates dead air and shade, which is pretty much going to be a second roof.
Yeah, it's already white. Second roof you say? Walls are also solid concrete so you sure that will work? Kinda always been hesitant to do anyhting because I am not 100% what will work.
People who build with shipping containers in the desert often make little awning roofs to make their structures inhabitable. Might be a good place to start researching.
If you live in a place that doesn't get much wind, you might try some sort of "shade sail" a few inches above your roof.
Silver paint, 99% reflectivity is worth a lot more than 80%.
I should add that the roof itself is not white, on the walls. The roof is unpainted concrete.
Well paint the roof. They almost certainly have paint specifically for that purpose.
What decrease in temp should I expect? I am thinking about what I should do if I am still not happy with the temperature decrease... Internal insulation? The ceiling is a little low already
Okay, just did some research, turns out they sell special “roof cooling” paints… Does anyone if these are gimmicks or not?
Example product:
https://leroymerlin.co.za/roof-raint-exterior-low-sheen-plascon-nuroof-cool-white-20l-81416861?refSrc=24238&nosto=nosto-page-product2
Does it not have a rubber roof membrane? Most flat roofs I've seen have an insulating foam layer between the rubber and the concrete
No, solid concrete.
>didn't put a layer of insulation between concrete pours
obviously a moat is the answer
get a second roof over it, people who live in RV trailers and shipping containers will tell you what a difference it makes not to have direct sunlight on your roof surface. If there are reasons that's not possible, the next best solution is an insulated air gap at the ceiling. like, get some wood-concrete glue, glue some lumber across the bottom of the roof then attach bubble foil or foam board across it. This will leave an air pocket that will trap the radiant heat. I've seen this used in old metal buildings that didn't have any insulation at all and it made a huge difference in minimizing summer time heat
If your problem is warm in summer and cold in winter I'd just use some ethene-based styrofoam and plaster it or some shit.
If your problem is heat and sun you could get some solar-absorbing collectors, either for electricity or heat.
Roof-mounted polyisocyanurate insulation board. R-3 per inch. Your problem is "easy". Chances are the old roof would need to come off in order to put down the insulation board because it needs to be epoxy applied to the concrete deck. There are mechanical fasteners made for this, but you're taking a huge risk of the concrete is old and shitty (i.e. breaking big chunks off driving fasteners through it). You can loose lay it with insulation board and membrane, but you would need ballast in the form of gravel or pavers to hold the fricker down. Local code might prohibit this as well if you live in a very high wind zone or hurricane zone.
>Oh, it's solid concrete
If you have a water proofing system like Tectum as the base, epoxy down polyiso, fully adhered membrane over the top. This is not a DIY application unless you want to spend 800 bucks on a two part epoxy spray backpack rig.
you could try attaching rigid foam insulation to the ceiling, or install ceiling joists so you can hang fiberglass or blow-in cellulose insulation within the joist bays