diff --git a/source/core/rendering/scene/hw_drawinfo.cpp b/source/core/rendering/scene/hw_drawinfo.cpp
index 101c5f29b..53bb84708 100644
--- a/source/core/rendering/scene/hw_drawinfo.cpp
+++ b/source/core/rendering/scene/hw_drawinfo.cpp
@@ -538,6 +538,7 @@ void HWDrawInfo::RenderScene(FRenderState &state)
 	drawlists[GLDL_MASKEDWALLSH].DrawWalls(this, state, false);
 	state.SetColorMask(true);
 
+	state.SetDepthBias(-1, 128);
 	state.SetDepthMask(false);
 	drawlists[GLDL_MASKEDFLATS].DrawFlats(this, state, false);
 	state.SetDepthMask(true);