diff --git a/code/modules/lighting/__lighting_docs.dm b/code/modules/lighting/__lighting_docs.dm
index 6ad0e32cdbc..5ac5897eb53 100644
--- a/code/modules/lighting/__lighting_docs.dm
+++ b/code/modules/lighting/__lighting_docs.dm
@@ -51,7 +51,7 @@ turf: (lighting_turf.dm)
   - proc/lighting_clear_overlays():
 	  - Delete (manual GC) all light overlays on this turf, used when changing turf to space
   - proc/lighting_build_overlays():
-	  - Create lighting overlays for this turf
+	  - Create lighting overlays for this turf. Called by ChangeTurf in case the turf is being changed to use dynamic lighting.
 
 
 atom/movable/lighting_overlay: (lighting_overlay.dm)
diff --git a/code/modules/lighting/light_source.dm b/code/modules/lighting/light_source.dm
index 73a65f064fc..2acddb4d298 100644
--- a/code/modules/lighting/light_source.dm
+++ b/code/modules/lighting/light_source.dm
@@ -246,6 +246,45 @@
 		effect_turf.Cut(idx, idx + 1)
 		effect_str.Cut(idx, idx + 1)
 
+//Whoop yet not another copy pasta because speed ~~~~BYOND.
+//Calculates and applies lighting for a single turf. This is intended for when a turf switches to 
+//using dynamic lighting when it was not doing so previously (when constructing a floor on space, for example).
+//Assumes the turf is visible and such.
+//For the love of god don't call this proc when it's not needed! Lighting artifacts WILL happen!
+/datum/light_source/proc/calc_turf(var/turf/T)
+	var/idx = effect_turf.Find(T)
+	if(!idx)
+		return	//WHY.
+
+	if(T.lighting_overlay)
+	  #if LIGHTING_FALLOFF == 1 // circular
+		. = (T.lighting_overlay.x - source_turf.x)**2 + (T.lighting_overlay.y - source_turf.y)**2 + LIGHTING_HEIGHT
+	   #if LIGHTING_LAMBERTIAN == 1
+		. = CLAMP01((1 - CLAMP01(sqrt(.) / light_range)) * (1 / (sqrt(. + 1))))
+	   #else
+		. = 1 - CLAMP01(sqrt(.) / light_range)
+	   #endif
+
+	  #elif LIGHTING_FALLOFF == 2 // square
+		. = abs(T.lighting_overlay.x - source_turf.x) + abs(T.lighting_overlay.y - source_turf.y) + LIGHTING_HEIGHT
+	   #if LIGHTING_LAMBERTIAN == 1
+		. = CLAMP01((1 - CLAMP01(. / light_range)) * (1 / (sqrt(.)**2 + )))
+	   #else
+		. = 1 - CLAMP01(. / light_range)
+	   #endif
+	  #endif
+		. *= light_power
+
+		. = round(., LIGHTING_ROUND_VALUE)
+
+		effect_str[idx] = .
+
+		T.lighting_overlay.update_lumcount(
+			lum_r * .,
+			lum_g * .,
+			lum_b * .
+		)
+
 #undef LUM_FALLOFF
 #undef LUM_DISTANCE
 #undef LUM_ATTENUATION
diff --git a/code/modules/lighting/lighting_turf.dm b/code/modules/lighting/lighting_turf.dm
index e261931c41c..f8f0a5ab102 100644
--- a/code/modules/lighting/lighting_turf.dm
+++ b/code/modules/lighting/lighting_turf.dm
@@ -17,6 +17,10 @@
 			var/atom/movable/lighting_overlay/O = PoolOrNew(/atom/movable/lighting_overlay, src)
 			lighting_overlay = O
 
+	//Make the light sources recalculate us so the lighting overlay updates immediately
+	for(var/datum/light_source/L in affecting_lights)
+		L.calc_turf(src)
+
 /turf/Entered(atom/movable/obj)
 	. = ..()
 	if(obj && obj.opacity)