My 1/2" thick Komatex (pvc) 4-story-open-air-parking-garage signs are warping in the So Cal desert heat (probably 115 degrees at peak). The signs are NOT at all exposed to the sun. ONLY exposed to the ambient air temps. 1/8" thick white pvc backers are mounted to the garage columns and the 1/2" thick black komatex signs are mounted to the white backers. I have a call into the mfr of the Komatex material but wondering if Signs101 members have had issues like this. Again, NO sun exposure. Just high heat. Thanks.