Gypsum board isn't going to help but I would look into your power supply first. If you're not getting ~13.8V (per rig's specs) you aren't going to get good performance. Also, consider your roofing material, height from ground, and proximity to metal/wiring because they all can muck things up.
There is a chance, based on antenna's height, you have a quasi-nvis antenna that isn't getting enough power and the signal just isn't being heard because your propagation is close to home (regional).
Having said that, I used a 10m dipole with my G90 for about a year (I used the tuner to get on other bands) and it was in the eave crawlspace of my Cape (up ~10ft-ish). I did reasonably well all things considered but it was somewhat directional.