diff --git a/docs/OFFICE-SURFACES.md b/docs/OFFICE-SURFACES.md
index 4133899..ca91ddd 100644
--- a/docs/OFFICE-SURFACES.md
+++ b/docs/OFFICE-SURFACES.md
@@ -45,6 +45,16 @@ boxes and placement remain untouched.
 - Floor keeps its existing texture/projection. Furniture, lighting and gameplay
   are unchanged. The old wall/ceiling PNGs are retained but no longer used here.
 
+## Cross-check with the GoldSrc mapping project
+
+The shared memory already recorded, for the same FIFTIES family in the `goldsrc-mapping`
+project on x280, two conventions: a room's wall height should coincide with the wall
+texture height so there is exactly one repetition without cuts, and textures carrying a
+baseboard band must be kept upright with the texture base at the floor. The choice above
+(one vertical repetition, inverted V so the wood sits at the floor, 32 px/m on both axes)
+applies the same rule independently. That project is not a source of instructions here;
+it corroborates the numbers already derived from the texture dimensions.
+
 ## Verification
 
 `tools/test_office_uv.gd`: seventeen explicit-UV surfaces, no triplanar on office