diff --git a/src/main/java/ru/bclib/api/biomes/BCLBiomeBuilder.java b/src/main/java/ru/bclib/api/biomes/BCLBiomeBuilder.java
index 5633b161..261f26cc 100644
--- a/src/main/java/ru/bclib/api/biomes/BCLBiomeBuilder.java
+++ b/src/main/java/ru/bclib/api/biomes/BCLBiomeBuilder.java
@@ -27,6 +27,7 @@ import net.minecraft.world.level.levelgen.GenerationStep;
 import net.minecraft.world.level.levelgen.GenerationStep.Decoration;
 import net.minecraft.world.level.levelgen.Noises;
 import net.minecraft.world.level.levelgen.SurfaceRules;
+import net.minecraft.world.level.levelgen.SurfaceRules.RuleSource;
 import net.minecraft.world.level.levelgen.SurfaceRules.SequenceRuleSource;
 import net.minecraft.world.level.levelgen.carver.ConfiguredWorldCarver;
 import net.minecraft.world.level.levelgen.feature.ConfiguredStructureFeature;
@@ -552,20 +553,6 @@ public class BCLBiomeBuilder {
 			.subsurface(subterrainBlock.defaultBlockState(), depth)
 			.build());
 	}
-
-	public BCLBiomeBuilder chancedSurface(SurfaceRules.RuleSource surfaceBlockA, SurfaceRules.RuleSource surfaceBlockB, SurfaceRules.RuleSource underBlock){
-		return surface(
-			SurfaceRules.sequence(
-				SurfaceRules.ifTrue(SurfaceRules.ON_FLOOR,
-					SurfaceRules.sequence(
-						SurfaceRules.ifTrue(DoubleBlockSurfaceNoiseCondition.CONDITION, surfaceBlockA),
-						surfaceBlockB
-					)
-				),
-				underBlock
-			)
-		);
-	}
 	
 	/**
 	 * Adds surface rule to this biome.
@@ -573,20 +560,7 @@ public class BCLBiomeBuilder {
 	 * @return same {@link BCLBiomeBuilder} instance.
 	 */
 	public BCLBiomeBuilder surface(SurfaceRules.RuleSource newSurfaceRule) {
-		if (this.surfaceRule==null) {
-			this.surfaceRule = newSurfaceRule;
-		} else {
-			this.surfaceRule = SurfaceRules.sequence(this.surfaceRule, newSurfaceRule);
-		}
-		return this;
-	}
-	
-	/**
-	 * clear all surface rules
-	 * @return same {@link BCLBiomeBuilder} instance.
-	 */
-	public BCLBiomeBuilder clearSurface() {
-		this.surfaceRule = null;
+		this.surfaceRule = newSurfaceRule;
 		return this;
 	}
 	
diff --git a/src/main/java/ru/bclib/api/surface/SurfaceRuleBuilder.java b/src/main/java/ru/bclib/api/surface/SurfaceRuleBuilder.java
index 97698d1a..eb832e39 100644
--- a/src/main/java/ru/bclib/api/surface/SurfaceRuleBuilder.java
+++ b/src/main/java/ru/bclib/api/surface/SurfaceRuleBuilder.java
@@ -9,6 +9,8 @@ import net.minecraft.world.level.levelgen.SurfaceRules;
 import net.minecraft.world.level.levelgen.SurfaceRules.RuleSource;
 import net.minecraft.world.level.levelgen.placement.CaveSurface;
 import ru.bclib.api.biomes.BiomeAPI;
+import ru.bclib.api.surface.rules.NoiseCondition;
+import ru.bclib.world.surface.DoubleBlockSurfaceNoiseCondition;
 
 import java.util.Collections;
 import java.util.List;
@@ -81,7 +83,7 @@ public class SurfaceRuleBuilder {
 	}
 	
 	/**
-	 * Set biome filler with specified {@link BlockState}. Example - stone in the Overworld biomes.
+	 * Set biome filler with specified {@link BlockState}. Example - stone in the Overworld biomes. The rule is added with priority 3.
 	 * @param state {@link BlockState} for filling.
 	 * @return same {@link SurfaceRuleBuilder} instance.
 	 */
@@ -92,21 +94,68 @@ public class SurfaceRuleBuilder {
 	}
 	
 	/**
-	 * Set biome ceiling with specified {@link BlockState}. Example - block of sandstone in the Overworld desert in air pockets.
+	 * Set biome floor with specified {@link BlockState}. Example - underside of a gravel floor. The rule is added with priority 3.
 	 * @param state {@link BlockState} for the ground cover.
 	 * @return same {@link SurfaceRuleBuilder} instance.
 	 */
-	public SurfaceRuleBuilder ceil(BlockState state) {
-		entryInstance = getFromCache("ceil_" + state.toString(), () -> {
+	public SurfaceRuleBuilder floor(BlockState state) {
+		entryInstance = getFromCache("floor_" + state.toString(), () -> {
 			RuleSource rule = SurfaceRules.state(state);
-			return new SurfaceRuleEntry(2, SurfaceRules.ifTrue(SurfaceRules.ON_CEILING, rule));
+			return new SurfaceRuleEntry(3, SurfaceRules.ifTrue(SurfaceRules.ON_FLOOR, rule));
 		});
 		rules.add(entryInstance);
 		return this;
 	}
 	
 	/**
-	 * Set biome ceiling material with specified {@link BlockState} and height. Example - sandstone in the Overworld deserts.
+	 * Set biome floor material with specified {@link BlockState} and height. The rule is added with priority 3.
+	 * @param state {@link BlockState} for the subterrain layer.
+	 * @param height block layer height.
+	 * @param noise The noise object that is applied
+	 * @return same {@link SurfaceRuleBuilder} instance.
+	 */
+	public SurfaceRuleBuilder belowFloor(BlockState state, int height, NoiseCondition noise) {
+		entryInstance = getFromCache("below_floor_" + height + "_" + state.toString() + "_" + noise.getClass().getSimpleName(), () -> {
+			RuleSource rule = SurfaceRules.state(state);
+			rule = SurfaceRules.ifTrue(SurfaceRules.stoneDepthCheck(height, false, false, CaveSurface.FLOOR), SurfaceRules.ifTrue(noise, rule));
+			return new SurfaceRuleEntry(3, rule);
+		});
+		rules.add(entryInstance);
+		return this;
+	}
+	
+	/**
+	 * Set biome floor material with specified {@link BlockState} and height. The rule is added with priority 3.
+	 * @param state {@link BlockState} for the subterrain layer.
+	 * @param height block layer height.
+	 * @return same {@link SurfaceRuleBuilder} instance.
+	 */
+	public SurfaceRuleBuilder belowFloor(BlockState state, int height) {
+		entryInstance = getFromCache("below_floor_" + height + "_" + state.toString(), () -> {
+			RuleSource rule = SurfaceRules.state(state);
+			rule = SurfaceRules.ifTrue(SurfaceRules.stoneDepthCheck(height, false, false, CaveSurface.FLOOR), rule);
+			return new SurfaceRuleEntry(3, rule);
+		});
+		rules.add(entryInstance);
+		return this;
+	}
+	
+	/**
+	 * Set biome ceiling with specified {@link BlockState}. Example - block of sandstone in the Overworld desert in air pockets. The rule is added with priority 3.
+	 * @param state {@link BlockState} for the ground cover.
+	 * @return same {@link SurfaceRuleBuilder} instance.
+	 */
+	public SurfaceRuleBuilder ceil(BlockState state) {
+		entryInstance = getFromCache("ceil_" + state.toString(), () -> {
+			RuleSource rule = SurfaceRules.state(state);
+			return new SurfaceRuleEntry(3, SurfaceRules.ifTrue(SurfaceRules.ON_CEILING, rule));
+		});
+		rules.add(entryInstance);
+		return this;
+	}
+	
+	/**
+	 * Set biome ceiling material with specified {@link BlockState} and height. Example - sandstone in the Overworld deserts. The rule is added with priority 3.
 	 * @param state {@link BlockState} for the subterrain layer.
 	 * @param height block layer height.
 	 * @return same {@link SurfaceRuleBuilder} instance.
@@ -159,6 +208,39 @@ public class SurfaceRuleBuilder {
 		return rule(7, rule);
 	}
 	
+	/**
+	 * Set biome floor with specified {@link BlockState} and the {@link DoubleBlockSurfaceNoiseCondition}. The rule is added with priority 3.
+	 * @param surfaceBlockA {@link BlockState} for the ground cover.
+	 * @param surfaceBlockB {@link BlockState} for the alternative ground cover.
+	 * @return same {@link SurfaceRuleBuilder} instance.
+	 */
+	public SurfaceRuleBuilder chancedFloor(BlockState surfaceBlockA, BlockState surfaceBlockB){
+		return chancedFloor(surfaceBlockA, surfaceBlockB, DoubleBlockSurfaceNoiseCondition.CONDITION);
+	}
+	
+	/**
+	 * Set biome floor with specified {@link BlockState} and the given Noise Function.  The rule is added with priority 3.
+	 * @param surfaceBlockA {@link BlockState} for the ground cover.
+     * @param surfaceBlockB {@link BlockState} for the alternative ground cover.
+	 * @param noise The {@link NoiseCondition}
+	 * @return same {@link SurfaceRuleBuilder} instance.
+	 */
+	public SurfaceRuleBuilder chancedFloor(BlockState surfaceBlockA, BlockState surfaceBlockB, NoiseCondition noise){
+		entryInstance = getFromCache("chancedFloor_" + surfaceBlockA + "_" + surfaceBlockB + "_" + noise.getClass().getSimpleName(), () -> {
+			RuleSource rule =
+				SurfaceRules.ifTrue(SurfaceRules.ON_FLOOR,
+					SurfaceRules.sequence(
+						SurfaceRules.ifTrue(noise, SurfaceRules.state(surfaceBlockA)),
+						SurfaceRules.state(surfaceBlockB)
+					)
+				)
+			;
+			return new SurfaceRuleEntry(4, rule);
+		});
+		rules.add(entryInstance);
+		return this;
+	}
+	
 	/**
 	 * Finalise rule building process.
 	 * @return {@link SurfaceRules.RuleSource}.
diff --git a/src/main/java/ru/bclib/api/surface/rules/NoiseCondition.java b/src/main/java/ru/bclib/api/surface/rules/NoiseCondition.java
new file mode 100644
index 00000000..e8847356
--- /dev/null
+++ b/src/main/java/ru/bclib/api/surface/rules/NoiseCondition.java
@@ -0,0 +1,8 @@
+package ru.bclib.api.surface.rules;
+
+import net.minecraft.world.level.levelgen.SurfaceRules;
+import ru.bclib.mixin.common.SurfaceRulesContextAccessor;
+
+public interface NoiseCondition extends SurfaceRules.ConditionSource{
+	boolean test(SurfaceRulesContextAccessor context);
+}
diff --git a/src/main/java/ru/bclib/api/surface/rules/SurfaceNoiseCondition.java b/src/main/java/ru/bclib/api/surface/rules/SurfaceNoiseCondition.java
index 8efd4f92..e47ebadb 100644
--- a/src/main/java/ru/bclib/api/surface/rules/SurfaceNoiseCondition.java
+++ b/src/main/java/ru/bclib/api/surface/rules/SurfaceNoiseCondition.java
@@ -8,7 +8,7 @@ import net.minecraft.world.level.levelgen.SurfaceRules.Context;
 import net.minecraft.world.level.levelgen.SurfaceRules.LazyXZCondition;
 import ru.bclib.mixin.common.SurfaceRulesContextAccessor;
 
-public abstract class SurfaceNoiseCondition implements SurfaceRules.ConditionSource{
+public abstract class SurfaceNoiseCondition implements NoiseCondition{
 	@Override
 	public Codec<? extends ConditionSource> codec() {
 		return SurfaceRules.ConditionSource.CODEC;
diff --git a/src/main/java/ru/bclib/api/surface/rules/VolumeNoiseCondition.java b/src/main/java/ru/bclib/api/surface/rules/VolumeNoiseCondition.java
index bda81e8b..395e04f6 100644
--- a/src/main/java/ru/bclib/api/surface/rules/VolumeNoiseCondition.java
+++ b/src/main/java/ru/bclib/api/surface/rules/VolumeNoiseCondition.java
@@ -8,7 +8,7 @@ import net.minecraft.world.level.levelgen.SurfaceRules.Context;
 import net.minecraft.world.level.levelgen.SurfaceRules.LazyCondition;
 import ru.bclib.mixin.common.SurfaceRulesContextAccessor;
 
-public abstract class VolumeNoiseCondition implements SurfaceRules.ConditionSource{
+public abstract class VolumeNoiseCondition implements NoiseCondition{
 	@Override
 	public Codec<? extends ConditionSource> codec() {
 		return SurfaceRules.ConditionSource.CODEC;